My Exoplanet Discoveries [Formerly "KIC 7848638 - My First Solar System"]

[Spaceception]

Hey guys, snip the posts before you post so it's not super long

 

Great finds!! The Moon from hell sounds cool!

[ProtoJeb21]

Later this weekend I will be doing a HUGE research update, releasing data about more than TWENTY new candidates. That's right, twenty. Over Columbus Day Weekend I had, like, nothing to do, so I spent several hours on two different days searching for additional candidates in known planetary systems. These include confirmed K2 systems or stars with very likely candidate planets listed on ExoFOP. About 13-17 of the >20 candidates are in such systems. The rest are completely new finds in completely new systems. In addition, I will be revealing updates to multiple systems I and other EE users have previously found. These include EPIC 212157262, EPIC 220194953-74, EPIC 228801451, and several more. Here are two systems from one of July's Daily Roundups with new parameters:

• EPIC 220364502: This is a red dwarf of about 0.36 R_Sol and 0.39 M_Sol where I found a potentially habitable candidate. With the new version of LcViewer, I was able to find out that it is most definitely real, but has two major drawbacks. The first is that there are NO other planets in the system, which is somewhat disappointing. Secondly, 220364502.01 is teetering very close to temperatures that would set it on a path to become a Super-Venus. However, there is something incredibly special about this planet: like Natalie, it has TWO stars. This planet presumably orbits the primary member of a wide red dwarf binary, with both members being about the same size. The secondary seems too far away from the primary and the planet to influence its climate. EPIC 220364502.01 is about 1.233 R_E (with an error of +10-40% due the binary companion), orbits every 22.497 days at 0.114 AU, and has an equilibrium temperature of 300^oK.
• EPIC 213044320: When I first reported this system, I thought I had found two potential habitable zone candidates around this rather large red dwarf (0.42 R_Sol and 0.48 M_Sol). However, with the new BLS search, it turns out that instead there is just one planet. I had mistaken some of this world's transit events for two entirely different planets. The new EPIC 213044320.01 is rather small at 0.79 R_E and has a year of just 4.693 days. As such it is a dry, inhospitable desert world baking at temperature of 557^oK (543^oF), hot enough to melt Tin, Bismuth, and Selenium.

That's all I'm going to reveal for now. I'm hoping to do more analyses of the planets I have yet to announce, and I hope to find even more for this research update. Stay tuned!

[ProtoJeb21]

RESEARCH UPDATE, 10/19/17

In the past two weeks, there have been enormous developments in the understanding, discovery, and even validation of candidate planets found by me, shutcheon, Vidar87, and others. I have managed to find over twenty new candidate planets, most of them are new additions to already known K2 systems. In addition, I will also present newly validated systems like EPIC-220194953-74, some of Vidar's newest candidates, and a very intriguing multi-planet system with 5 to 7 Super-Earth planets.

COLUMBUS DAY WEEKEND CANDIDATES

As I mentioned in a status update earlier, over Columbus Day Weekend I did a huge analysis on multiple known K2 systems. Using the online K2 database called ExoFOP, I first filtered for known red dwarf systems. These were stars with known planet candidates that fell into a size range between 0.05 and 0.6 R_Sol, and had temperatures no more than 4,000^oK. Over several hours I managed to go through every single star that appeared in my filter results. In the end, 8 of those had completely new planet candidates that no one had stumbled upon before. What was quite intriguing was the abundance of what I call SOCIS (Spaced-Out Close-In Systems). These usually contain two planets, sometimes three. The first has an incredibly close-in orbit, lasting 1.5 days or less (there planets were always the previously known ones). Meanwhile, the second (or third) planet(s) had orbits lasting anywhere from several days to over two weeks. One of these outer planets actually orbits within the optimistic habitable zone of its system.

• EPIC 201239401: The first and one of my favorite SOCI Systems I have found. The first planet, a known candidate, is 1.52 times the size of Earth and orbits in a mere 0.9055 days. I found a second candidate of 0.74 R_E with a period of 6.784 days and a pretty good sigma confidence of 9.299. With an equilibrium temperature of 427 K, it's non-habitable but not that bad in cosmic standards.
• EPIC 201650711: This is the most extreme SOCIS found during my search, even though it was only the second one I stumbled across. EPIC 201650711.01 has been analyzed by both Vanderurg et al. and Adams et al., with the latest result being reported on July 7th, 2016. It is a very quick-orbiting planet with one of the shortest years ever seen  - just 0.25699 days, or only 6.232 hours. As a result, this 0.769 R_E planet is likely made almost entirely of iron and will have incredible volcanic activity, far exceeding Jupiter's moon Io. After the initial shock of such a freakish planet, I managed to find a small 6.302-sigma signal of a 0.40 R_E planet orbiting every 5.546 days. Candidates 01 and 02 of this system have the widest mean-motion resonance I have ever seen, with C01 orbiting about 21 times for ever one orbit of C02.
• EPIC 201785059: One of the smallest stars I analyzed (just 0.28 R_Sol), this red dwarf is the one with the potentially habitable candidate I found. EPIC 201785059.02 is a "Warm Mars" with a radius of 0.60 R_E and a year of 17.894 days, placing it within the optimistic habitable zone with a temperature of 284^oK. While promising, it's one of the least likely candidates I found, with a sigma of 6.313 and a rather poor-looking folded transit. The innermost planet was found in 2015 and is about 88% the size of Earth with a year of 1.395 days. The two have the widest orbital separation of any planets in any SOCI System.
• EPIC 206215704: Probably the weirdest SOCIS I found. The first planet is a 2.52 R_E Mini-Neptune with a year of just 0.623 days (~15 hours). With LcViewer, a pair of TROJAN PLANETS are found. The two Super-Earths are 1.56 and 1.59 times the size of Earth with years of 2.256 and 2.908 days, and sigma values of 13.673 and 12.891. In other words, they are most likely real. Such a system teases the theories of orbital stability and planet formation, as these three worlds are in such precarious orbits while being very close to a high-density star.
• EPIC 206298289: One new planet of 0.78 R_E was found orbiting every 3.214 days, sigma of 9.879, temperature of 543^oK. While the new candidate I found isn't very interesting, what makes things peculiar is its potential influence from the innermost candidate. It is a large Super-Earth around 1.62 times Earth's radius hugging its red dwarf host in a 0.435-day (10.44 hours) orbit. A planet that large with an orbit that close is likely wobbling its star very violently, possibly resulting in the orbit of C02 becoming more inclined and/or eccentric.
• K2-91/EPIC 211077024: This system contains one confirmed planet, K2-91b, orbiting every 1.4195 days. I managed to find a very similar and very likely second signal of a 0.88 R_E planet with a 1.441-day year, sigma of 32.823. This second candidate could potentially be a real find, or it may suggest that the K2-91 system is an eclipsing binary.

After combing through all the listed red dwarf candidate systems on ExoFOP (there are many more that exist but weren't listed on the site), I turned my attention to larger stars of over 0.7 solar radii. There were a LOT of them, so I was only able to go through a third of the stars that appeared in my new filter. Despite that, three systems ended up being quite fruitful.

• K2-8/EPIC 201445392: A confirmed system of two Mini-Neptunes orbiting a star 80% the size of the Sun. They are almost exactly in a 2:1 mean-motion resonance, with periods of 5.064 and 10.352 days. I managed to find an additional two candidates orbiting every 1.939 and 3.296 days, both in resonance with each other and K2-8b and c. They are between 0.79 and 1.01 Earth radii and are likely molten worlds.
• EPIC 201497682: A second four-planet system I stumbled across. The two known planets are 1.57 and 1.96 R_E and take 7.799 and 13.838 days to orbit their orange dwarf star. Two more candidates were found, the first being a 0.91 R_E candidate with a year of 2.132 days and a scorching temperature of 1,033^oK. The second orbits every 3.884 days, is 6% larger than Earth, and has a somewhat cooler temperature of 846^oK.
• K2-11/EPIC 201596316: One confirmed planet orbits the star every 39.9377 days. It is yet another warm Mini-Neptune, and appears to have a companion planet with a radius of 0.61 Re and a much shorter year of 2.181 days. 
• K2-12/EPIC 201613023: An F-Type main sequence star with a confirmed hot Mini-Neptune roasting at over 1,000 degrees Kelvin. It has proven to be one of the most fertile systems I've ever come across, with 5 new candidates being found by LcViewer's BLS search. One of them is most likely a false positive, but the others hold potential. In order from the star, they are 0.56, 0.88, 0.99, and 1.13 R_E, with orbital periods of 1.815, 5.604, 12.249, and 35.203 days. The innermost planet has a temperature of over 1,500^oK and is likely a molten, volcanic hellhole.
• K2-36/EPIC 201713348: Another orange dwarf with a hot Mini-Neptune. At first the system seems rather boring, but I managed to find a planet of about 0.875 R_E with just about the same orbital period as K2-36b. It could potentially be another Trojan Planet.

NEWLY VALIDATED CANDIDATES

Recently, two new papers were published by Dressing et al. and Hirano et al. The first study led to the validation of 16 new K2 planets. Two of them were found by Exoplanet Explorers users.

• K2-117c: This planet was stumbled upon by @Cabbink during May of this year. It is a little over twice the radius of Earth and has an eccentric (e = 0.15) orbit lasting 5.444820 days around a small orange dwarf. A search for Transit Timing Variations by Hirano et al. did not find any significant gravitational influences from this planet, suggested a volatile-rich composition.
• K2-120b: Originally designated EPIC 211791178.01, this planet gained a lot of attention back in late May or its odd folded transit, originally thought to be caused by a potential exomoon and first pointed out by Libmar96. While such a moon is not likely to exist, the planet itself was recently confirmed. It is 2.01 R_E and takes 9.562748 days to orbit an orange dwarf about 67% the radius of the Sun.

The second paper was published earlier this week or weekend by Hirano et al. It takes a look at over a dozen new candidate worlds around red dwarfs stars of various sizes and metal content. One of those systems appears to have a lot more planets than originally thought - which I'll get to later. The most important find (to us EE users) is the validation of the EPIC 220194953-220194974 system. If you remember, this was a binary red dwarf system with three sub-Earths found by Vidar to be orbiting one of the stars. Hirano et al. managed to find the actual sizes of the two stars, which are much larger than expected. The primary, EPIC 220194974, is 0.65 R_Sol, 0.632 M_Sol, and has a temperature of 4079^oK and is 10.1% as luminous as the Sun. It is likely a K9.0V dwarf, even though its spectral type is not mentioned in the paper. EPIC 220194953 is not that much smaller at 0.598 R_Sol and 0.575 M_Sol with a temperature of 3854^oK and 0.066 times the Sun's luminosity. The two orbit each other at a distance of 1,100 AU (about 1.64557e+11 km). Because of their larger than expected sizes, the three planets are also much larger, at 1.33, 1.73. and 1.64 times the size of Earth. Significant TTVs were not found, suggesting that the innermost planet lacks an iron core, while the outer two are likely Water Giants. They have equilibrium temperatures of 674, 579, and 516 degrees Kelvin, hot enough to melt only a few types of metals and non-metals. The three planets receive between 50 and 16 times the stellar radiation Earth gets from the Sun.

EPIC 211428897 has been studied in another research paper that was recently published. Two of the four extra candidates shutcheon and I have found were officially recognized - the 2-day planet (my find) and the 4-day planet (shutcheon's find). In addition, the team used the Keck telescopes to get an image of the star...or stars, for that matter. It's also another binary system. I am under the assumption that the planets are around the same size as Earth and orbit the primary, but I could be wrong. The system still has a lot more analysis to be done on it.

OTHER FINDS

Several new candidates were found around EPIC 220522664, a system described by Hirano et al. The team only found one planet, but Vidar87 found three more with orbital periods of 16.379, 21.394, and 60.307 days. Both shutcheon and I did additional analyses of the SFF and Everest2 data for the star. Shutcheon found that the 60-day period doesn't exist, but there is a likely planet (C05) orbiting every 28.742 days. I did an even deeper analysis, using the BLS search on both the Everest2 and SFF data of EPIC 220522664. I found all the planets described by Vidar and shutcheon in both light curves, along with a Super-Earth orbiting every 37.170 days within the habitable zone. But then there was the issue with C05. While it was easily found by the BLS search in the Everest2 data, the code found two separate candidates instead within the SFF data. One was a sub-Earth of about 0.8 R_E orbiting every 4.635 days, while the other was a larger Super-Earth in a 56.598-day orbit. Both had a high statistical significance, but I don't know what to do with them since they may actually just be C05. A comprehensive list of the candidates can be found below.

• C07???: 0.91 R_E, 4.635 days, 0.045759 AU, 560^oK, 10 sigma.
• C01: 1.640 R_E, 11.332 days, 0.083045 AU, 416^oK.
• C02: 1.693 R_E, 16.379 days, 0.10616 AU, 368^oK.
• C03: 1.996 R_E, 21.394 days, 0.12685 AU, 337^oK.
• C05: 1.480 R_E, 28.742 days, 0.15445 AU, 305^oK
• C06: 1.525 R_E, 37.170 days, 0.18333 AU, 280^oK. Potentially habitable planet!
• C08???: 1.81 R_E, 56.598 days, 0.24265 AU, 243^oK, 8 sigma. Potentially habitable planet!

Most of the planets in this system are likely rocky, due to the host star's high metallicity of +0.11 [Fe/H]. Candidates 03 and 08 could have a rather large amount of water and hydrogen. However, it's also possible that C03 is a Mega-Earth with extreme volcanism and plate tectonics. C06 is possibly a world covered in both water and land, while C08 is an oceanic world.

Vidar87 has managed to find multiple very likely planet candidates around M and K-type stars over the last two weeks. Most of them have very short orbital periods of just a few days or less. Shockingly, some of those very close-orbiting worlds are comparable in size to Neptune and Gliese 1214b.

• EPIC 236235077: A small K-dwarf found inside a star cluster in Campaign 11. It may have a binary companion. Vidar found an Earth-sized planet with nearly 30 sigma orbiting once every 7.8 hours. As a result it is likely incredibly volcanic and has a temperature of over 1,773^oK (2,731^oF), one of the highest temperatures ever for a planet around such a small star.
• EPIC 220526079: An even smaller orange dwarf (0.56 solar radii) with a Mini Neptune candidate of about 2.45 R_E orbiting once every 7.5 days.
• EPIC 220436943: A 0.632 solar radius K-dwarf with a shockingly close-in Mini Neptune of 2.5 R_E. Orbiting a mere 2.438 days, it has an equilibrium temperature of almost 900 Kelvin.
• EPIC 212526681: Two likely Super-Earths orbit this small orange dwarf of 0.525 R_Sol. The first is 1.35 R_E and orbits every 7.084 days; the second is larger at 1.5 R_E and takes 13.012 days to orbit its star. The two planets have temperatures of 563 and 461^oK.
• EPIC 212328538: A red dwarf nearly half the size of the Sun with a likely Super-Earth candidate (~1.4 R_E) orbiting every 3.565 days. Its equilibrium temperature of 638^oK suggests that if rocky, some types of liquid metals may exist on the surface.
• EPIC 211566738: Similar in size to the previous star, this red dwarf has a very short-period planet only about 5% larger than Earth. With a year of just 0.761 days (18.264 hours), tidal forces likely have melted this planet entirely and raised its temperature far about its T_eq of 1,058^oK (1,445^oF).
• EPIC 206414361: This star's size and temperature puts it right on the border of an M-dwarf and a K-dwarf. It has a rather large Super-Earth of about 1.65 R_E orbiting every 3.476 days. Because of its large size and high equilibrium temperature of 701^oK (802^oF), it could be a broiled planet similar to @StarCrusher96's Iain - a somewhat gaseous world with a hot rocky surface below a violent atmosphere.

Over the weekend I did an in-depth analysis of EPIC 228801451, a 0.85 solar radius star with a multi-planet system. Original observations showed two planets with easily defined orbits and signs of a third Mini-Neptune planet. Using LcViewer's BLS search, I was able to pin down the orbit of the third planet: about 33.313 days. It is 2.94 R_E and MUCH cooler than the two inner worlds. The first is 1.10 R_E and, with a year of just 14 hours, is broiled at temperatures of nearly 3,000^oF. Only less than a dozen elements, including Osmium and Molybdenum, can stay solid at these temperatures. The second is a 2.12 R_E planet (presumably a hot gas dwarf) in an 8.329-day orbit with temperatures around 781^ok (946^oF).

I managed to find the research paper where EPIC 212157262.01 (Hemithea) was first reported. It is smaller than I expected, with a radius of 2.97 R_E. While I thought it was a Hot Neptune, the paper gives it a density of 2.739 g/cm³, which implies a surprisingly high mass of about 13.015 M_E. When plotted on Sara Seager's exoplanet mass-radius relationship graph, Hemithea falls just above the "100% H²O" line. This means that instead of being a hot puffy ice giant, Hemithea is instead a world made of up to 90% water, with about 5-10% hydrogen/helium and 5-10% silicates and iron. The upper atmosphere of this planet would be pure H/He before transitioning to a mix of water vapor and hydrogen. As you go down further, the air becomes increasingly denser before giving way to a "plasma-water" ocean, similar to that of Gliese 1214b. It's possible that on the top of the ocean, it could be almost like an Earthly monsoon climate, except over 1,000^oF with incredibly high pressures and no land. The plasma ocean is incredibly hot, but kept liquid due to enormous atmospheric pressure. Deeper in the ocean, the water becomes an incredibly hot and molasses-like soup, before you would reach a solid shell of Ice-VII and Ice-X surrounding a rock and iron core. Absolutely bizarre. It also turns out that EPIC 212157262.02 (Arethusa) is smaller than originally calculated, at just under 2 R_E.

 

That's everything from the last few weeks of exoplanet research. This is probably my longest post ever, but something tells me it won't be for long. With more and more scientists taking notice in our work on Exoplanet Explorers, it is very likely that even more of our candidates will be confirmed by the time 2017 draws to a close.

Edited October 20, 2017 by ProtoJeb21

[Cabbink]

2 hours ago, ProtoJeb21 said:

K2-117c: This planet was stumbled upon by @Cabbink during May of this year. It is a little over twice the radius of Earth and has an eccentric (e = 0.15) orbit lasting 5.444820 days around a small orange dwarf. A search for Transit Timing Variations by Hirano et al. did not find any significant gravitational influences from this planet, suggested a volatile-rich composition.

Volatile rich? huh.
anyways, if i get any say in this, the unofficia name of the planet should be Palnos, a butchered version of the word "React" in Latin.
Thanks for the updates!

[Cabbink]

*cough* im constructing a EE Discord for all o us *cough*
Heres a preview....
 

Spoiler

 

[ProtoJeb21]

No time for a proper introduction - this time, I'm going straight into some of the most important discoveries and updates of the last two-ish months. More stuff will be coming later.

• EPIC 210897587: Vidar's three-planet system of Super-Earths around a red dwarf was confirmed! Twice, to be exact. On Monday the 22nd, Deiz Alonso et al published a paper titled "A system of three transiting super-Earths in a cool dwarf star", which validated all three candidates and resized both them and the star. The results are disappointing but at the same time very exciting. The star (now known as LP415-17) is almost twice as large as originally expected, with about 58% the radius and 65% the mass of the Sun and a temperature of 4258 K. This makes it a K6V main sequence orange dwarf. The three planets - designated LP415-17b, c, and d - are much larger than originally calculated, with radii of 1.80, 2.60, and 1.90 R_Earth. The authors also gave likely masses for the planets based off of Geoff Marcy's mass-radius relationship equation: 4.70 M_Earth for b, 6.50 M_Earth for c, and 4.90 M_Earth for d. As expected, the planets are significantly hotter than before, with equilibrium temperatures of 603 K (626 F), 465 K (377 F), and 325 K (125 F) for an albedo of 0.3. While this seems to kill the potential habitability of LP415-17d, I believe that its position in the system and likely high water content have resulted in a cloudy atmosphere of reflective water clouds. This could bump the planet's albedo up to 0.7, reducing its equilibrium temperature to 263 K (14 F), and protecting the watery surface from too much heat. But things can never be simple, can they? Literally just ONE DAY later, Teruyuki Hirano et al came out with their own analysis, giving the star slightly smaller parameters and validating the system as K2-155. Their results put the star at 0.526 solar radii and 0.540 solar masses with a temperature of 3919 K and a luminosity 0.059 times that of the Sun. The three planets, K2-155b, c, and d, are significantly smaller and cooler than in the previous paper. They are 1.55, 1.95, and 1.64 R_Earth with equilibrium temperatures of 537 K (507 F), 414 K (286 F), and 289 K (61 F), assuming albedoes of 0.3. The latter is likely an ocean planet with a cloudy, reflective atmosphere. No mass estimated were given this time, but based on their sizes I calculate the masses to be about 4.5 M_Earth for K2-155b, 3.5 M_Earth for K2-155c, and 2.6 M_Earth for K2-155d. Hirano's paper can be found here. What's very exciting is that the star is one of the brightest M/K dwarfs with transiting planets, and at least the first team hopes to get radial velocity measurements of the planets and observe at least K2-155d with the James Webb Telescope.
• EE-1: In case somehow nobody noticed, this system was recently confirmed as K2-138. Five planets, K2-138b, c, d, e, and f, were validated, while the sixth, K2-138g, was reported as a very likely candidate. I made a huge post on Imgur about the system if you want to learn more. This discovery helped revive Exoplanet Explorers, and now those same scientists are working to validate even more planets found by us citizen scientists. https://imgur.com/gallery/N7CGb
• EPIC 220522664: Now validated as K2-148, this system has one planet reported and validated by Hirano et al, and multiple more found by me, Vidar87, and shutcheon. I did a thorough re-analysis of the system earlier this month and got my most accurate parameters yet for the system. It turns out the system likely hosts SIX planets, but unlike EPIC 220221272 (which I'll get to in a bit), they are much more spread out. The parameters I got for the final three planets, all of which are near or in the habitable zone, were much different than from original analyses. However, these are by far the most likely parameters, and at least the final two planets are temperate ocean planets.
  • K2-148b: 1.640 R_Earth, 11.332989 days, 0.083088 AU, 416 K (289 F), 8.247 flux, 17.6 sigma.
  • C02: 1.604 R_Earth, 16.354655 days, 0.106106 AU, 368 K (203 F), 5.057 flux, 10.1 sigma.
  • C03: 1.981 R_Earth, 21.353274 days, 0.126757 AU, 337 K (147 F), 3.544 flux, 15.8 sigma.
  • C04: 1.645 R_Earth, 27.476848 days, 0.149953 AU, 310 K (98 F), 2.532 flux, 8.4 sigma.
  • C05: 1.760 R_Earth, 34.312499 days, 0.173892 AU, 287 K (57 F), 1.883 flux, 8.4 sigma.
  • C06: 1.835 R_Earth, 60.385010 days, 0.253472 AU, 238 K (-31 F), 0.886 flux, 11.9 sigma.
• EPIC 220194974: I mentioned that this system was validated a few months ago. Now it has been re-designated as K2-149, and its planets are now K2-149b, c, and d. The star is confirmed to be gravitationally bound with EPIC 220194953.
• EPIC 220221272: Based on a new method of calculating stellar parameters I learned from Planet Hunters, it turns out the star is likely just about the same size or smaller than its originally calculated values. It could be around 0.20 Solar radii and 0.225 Solar masses with a temperature of 3551 K and just 0.57% the Sun's luminosity. The five likely planets (that final one likely doesn't exist) are much smaller and colder than before. The fourth planet could be potentially habitable, or just a Venus-like planet.
  • C03: 0.703 Re, 2.231580 days, 0.02034 AU, 491 K (424 F), 13.79 flux.
  • C04: 0.690 Re, 4.194269 days, 0.03097 AU, 398 K (257 F), 5.95 flux.
  • C02: 0.693 Re, 6.681050 days, 0.04224 AU, 341 K (154 F), 3.20 flux.
  • C05: 0.809 Re, 9.713093 days, 0.054213 AU, 301 K (82 F), 1.94 flux.
  • C01: 1.326 Re, 13.622729 days, 0.06793 AU, 269 K (25 F), 1.24 flux.
• HD 284032b: A horrifying new candidate found by maddendd on Exoplanet Explorers. It's 3.24 times the size of Earth and takes about 1.39 days to orbit a very hot, very bright A2V main sequence star known as HD 284032. Some quick calculations reveal that this planet is one of the most hostile places in the Universe, with an equilibrium temperature of at least 3,648 K (6,107 F) while receiving over 42,000 times more energy from its star than Earth does from our Sun. The environment is so hostile that any atmosphere would've been ionized and blow away, likely making HD 284032b an enormous Hyper-Earth. In addition, the radiation from HD 284032 would likely be enough to turn you into nothing more than a diffuse, incredibly hot cloud of free protons, neutrons, and electrons.

[Cabbink]

Hey, at least it isnt as bad as tartarus. shudder

[ProtoJeb21]

A lot of systems found by me and others on Exoplanet Explorers have been validated by Mayo et al., so expect a huge post covering them sometime today or tomorrow. I will also be presenting more interesting new finds as well, including a new five-planet system. 

[ProtoJeb21]

Some amazing stuff has happened today and I want to share it so badly...but I must restrain myself. The time is not right. By the end of the month you may see what I am taking about. 

In the meantime, I will do a post regarding some newly validated systems on Wednesday or Thursday. 

[ProtoJeb21]

19 NEWLY VALIDATED EXOPLANET EXPLORERS CANDIDATES!

Today marks the one month anniversary of a very special paper. On February 15th, an extensive research paper by Mayo et al validated almost 100 new K2 candidates, 19 of which were originally reported on Exoplanet Explorers. However, this was all an independent study from EE, so we weren't given any credit. I'm not really disappointed, because now all these worlds can be studied in even greater detail than before. Plus the lead author is just an undergraduate, so this is a huge achievement for him. The paper can be read HERE, and includes planets from Campaigns 1 through 10. Unfortunately, this study was only focused on (relatively) bright stars in the K2 fields, so no red dwarf systems were a part of this. Now for the validated systems and what their planets are now like.

EPIC 201132684: Four candidates orbit this star: three periodic planets orbiting every 6, 10, and 25 days, and a much larger long-period candidate within the habitable zone. Only the 10-day Mini Neptune was validated, given the name K2-158b. None of the other candidates were mentioned, even though my analyses show they are likely to exist. In fact, a LOT of likely candidate planets, even in some other validated systems, were not included (I'm looking at you K2-203). K2-158b is your typical run-of-the-mill hot Mini Neptune, with a radius of 2.63 R_⊕ and a temperature around 765 K (917 F; 492 C). K2-158 is not a whole lot larger and hotter than previously expected, at 89.2% the radius and 93.3% the mass of the Sun with a temperature of 5489 K.

EPIC 201528828: I found three likely planets orbiting this star several months back, and all of them were validated as K2-165b, c, and d. The host star is a bit larger than initial assumed at 80.4% the radius and 83.5% the mass of the Sun, with a temperature of 5185 K. K2-165b is a hot likely rocky Super-Earth of 1.27 R_⊕ orbiting every 2.35 days, with a surface temperature around 1,134 K (1,582 F; 861 C). K2-165c is significantly larger at 1.55 R_⊕. It orbits almost twice as long as K2-165b, with one year lasting 4.38 days - as a result it is somewhat cooler at 922 K (1,200 F; 649 C). Finally, there is the hot Mini-Neptune K2-165d, with a radius of 2.65 R_⊕ and a much longer orbital period of 14.10 days. It's temperature is "only" around 625 K (665 F; 352 C). 

EPIC 211562654: This compact, hellish 5-planet system was first found by shutcheon over the summer. In this study, three of his candidates were validated as K2-183b, c, and d. The innermost one, K2-183b, is one of the most horrific and inhospitable worlds yet found in the K2 mission. It's far larger than expected, at 2.60 R_⊕, due to an orbit that only grazes the disk of its star. One year takes just 0.469 days (11.3 hours) to complete, roasting the planet to a whopping 2,097 K (3,315 F; 1,824 C). The sheer size and temperature of K2-183b (along with getting about 4,600 times more radiation than Earth) means that it is likely a Hyper-Earth - specifically, a new class of planets I call COSSNs (Closely Orbiting Scorched Sub-Neptunes), which are close-in (<1.5 days) and/or hot (>1,600 K) planets between 1.60 and 5.00 . This category can be divided up into Mega-Earths (rocky planets of 10-30 M_⊕), Hyper-Earths (>30 M_⊕), and Chthonic Neptunes (>3.00 R_⊕). For a rocky composition, K2-183b is likely around 36.0 M_⊕, giving it a density of 11.3 g/cm³ and over 5.3 times Earth's surface gravity. The next two validated planets, K2-183c and d, are twin Mini-Neptunes of 2.51 and 2.54 R_⊕, with orbital periods lasting 10.79 and 22.63 days. They are much cooler at 737 K (867 F; 464 C) and 576 K (577 F; 303 C). Two smaller likely candidates not mentioned in the paper - K2-183.05 and K2-183.04 - reside between planets b and c, with orbital periods of 2.15 and 4.25 days. Using the new parameters for the host star (87.3% the radius and 94.2% the mass of the Sun, temp of 5482 K), these two worlds are 1.12 and 1.19 R_⊕, with temperatures of 1,262 K (1,812 F; 989 C) and 1,006 K (1,351 F; 733 C).

EPIC 212157262: Out of all these newly validated systems, this is the one I'm most proud about. Four of the five candidates around EPIC 212157262 have now been validated as K2-187b, c, d, and e in order from the host star. Despite changes to their physical parameters, they will keep their nicknames of Rhoeo, Chyone, Hemithea, and Erethusa. K2-187 is slightly smaller than the last study it was featured in. It is now determined to be 89.5% the radius and 96.7% the mass of the Sun with a temperature of 5477 K. In addition, K2-187 is extremely metal rich, with a metallicity of +0.26 dex, indicating it has about twice the Sun's content of heavy elements and likely hinting at heavyweight compositions for some of its planets. Whipping around its star in just 0.774 days (18.6 hours) is the hellish K2-187b/Rhoeo. At 1.38 R_⊕ and 1,788 K (2,759 F; 1,515 C), it is the smallest and hottest planet of the system. The front side likely exceeds temperatures of 2,000 K (3,140 F; 1,727 C) and may be enough to vaporize certain metals. One some parts of the planet, magma may rain out of the sky. At least half the planet is covered in a broiling magma ocean. It's close proximity to K2-187 has likely led to enormous volcanic activity like on 55 Cancri e, where eruptions could create volcanic plumes hundreds, if not thousands, of kilometers tall and wide. However, its orbit is about 4 degrees tilted from those of the other three validated planets. This is likely the work of K2-187c/Chyone. At 1.70 R_⊕, it could be rocky, and would need to be a whopping 7.1 M_⊕ to have a terrestrial composition. It's gravity could be enough to mess with the orbit of its hellish inner sibling. It orbits every 2.87 days (almost exactly 4 times longer than K2-187b's year) and has a temperature of 1,155 K (1,619 F; 882 C). Next out is K2-187d/Hemithea, a rather large Hot Neptune of 3.22 R_⊕ orbiting every 7.15 days with a temperature of 852 K (1,074 F; 579 C). Beyond that is the Mini Neptune-sized planet K2-187e/Erethusa, at 2.26 R_⊕ with an orbital period of 13.61 days and a temperature of 687 K (777 F; 414 C). It's size and temperature, along with K2-187's high metal content, indicate that it could be mainly rocky with a large fraction of its mass as water, either in the form of a thick steam atmosphere, or a supercritical ocean, or both. The final candidate of the system, EPIC 212157262.05/Polyphonte, was not mentioned in the paper, and seems quite dubious. If its exists, it is 1.57 R_⊕, orbits every 21.83 days, and has a temperature of 587 K (597 F; 314 C).

K2-201: I forgot that I spotted the now-named K2-201b months before the paper was released. It is a very hot Super-Earth of 1.40 R_⊕ taking 1.06 days to orbit a Sun-like star. It's surface temperature is around 1,618 K (2,453 F; 1,345 C). There is a Hot Neptune further out that somehow I didn't find.

K2-214, K2-215, K2-217, K2-220, and K2-222: All of these are single-planet systems with hot Mini-Neptunes and Neptunes orbiting around Sun-like stars. Similar to K2-201b, they are worlds that I found but forgot about. Nothing much is to note about them.

EPIC 228801451: The final system of the day is also quite cool. It is now known as K2-229, and is the second-to-last system in the confirmed K2 catalog as of now. The star was revealed to be 80.2% the radius and 85.8% the mass of the Sun, with a temperature of 5231 K. This is close to my predictions using the star's J-H-K magnitude values provided by the 2MASS project. The first two of its three candidates were mentioned and validated, now sporting the names K2-229b and c. K2-229b has one of the shortest orbital periods of any planets I have yet found, taking just 0.58 days (~14 hours) to orbit its star. It has a radius of 1.25 R_⊕ and a temperature of about 1,811 K (2,800 F; 1,538 C). K2-229b's extremely close proximity to its star has also likely led to enormous volcanism, possibly even more than K2-187b. In fact, tidal forces are likely so strong that the entire crust may have melted into a broiling global ocean of magma and exploding volcanoes. Molten rock rain is also likely in the forecast. The next planet out is the 2.16 Mini-Neptune K2-229c. It takes 8.33 days to orbit the star and has a Venus-like temperature of 747 K (885 F; 474 C). The planet could be mainly rocky with a steam envelope, similar to K2-187e. The unmentioned third candidate, K2-229.03, still remains very likely. Using the duration of its single transit and the newfound parameters for the host star, the planet is a 2.20 R_⊕ Mini-Neptune or ocean world taking no less than 89.61 days to orbit. Its maximum possible temperature is around 338 K (149 F; 65 C). This raises hope that, despite hosting one of the most hellish worlds I have ever found, K2-229 may also be a home to a potentially life-friendly place.

 

Those are all the newly validated planets from Exoplanet Explorers. In a few days I will do another research update, featuring my best finds of K2 Campaign 14. I just finished my 3-month analysis of the campaign on Tuesday, and I have a LOT of cool, weird, and hellish finds to present. Stay tuned!

 

[FleshJeb]

I am out of likes for the day. Fantastic work! I very much need to catch up on this thread.

[ProtoJeb21]

I have some HUGE discoveries to reveal soon, but I'm not finished with some final analyses. Here's a teaser at something...very special:

Edited March 24, 2018 by ProtoJeb21

[ProtoJeb21]

MASS FOR K2-229b!

No, this isn't the special discovery I teased the other day. Not by a long shot. Just today, a paper was released that presented the most accurate parameters for the K2-229 (EPIC 228801451) system yet, including radial velocity measurements for planets b and c. K2-229b has been re-evaluated at 1.165 ± 0.066 R_⊕, significantly smaller than before due to its host star also being slightly smaller. At this radius, K2-229b shouldn't be too massive, likely around 1.6 to 1.8 for an Earth-like composition.

If it HAD an Earth-like composition.

Because of its extreme proximity to K2-229 - one orbit takes just 14 hours to complete - I had a lingering suspicion that K2-229b would be iron-rich. This is revealed to be the case. With a mass of 2.59 ± 0.43 M_⊕, K2-229b is made of almost 70% iron, very similar to Mercury. In fact, K2-229b is probably the closest planet yet found to Mercury, in terms of composition. The planet has a high density of 9.03 g/cm³ and a strong surface gravity of about 1.9g - for comparison, Eve has 1.7g of gravity. K2-229b is also unbelievably hot, with a temperature calculated at 1,960 K (3,068 F; 1,687 C). This is more than hot enough to melt iron and vaporize certain rocks and metals. It is expected that most, if not all, of K2-229b's surface is covered in molten rock, maybe with some sandy landmasses on the back side. And by "sand", I mean broken up volcanic glass. Fun.

K2-229c was also further studied, with a radius of 2.12 ± 0.11 R_⊕ and a mass less than 21.3 M_⊕. It remains a possibility that the planet is also very dense like K2-229b and possibly a hot Mega-Earth. It is also quite hot at 800 K (980 F; 527 C).

More info about the new findings can be found below:

https://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=K2-229&type=PLANET_HOST

https://www.nature.com/articles/s41550-018-0420-5

[ProtoJeb21]

I'm sorry that I'm incredibly late for releasing all the new discoveries over the last several months, and I'll try to get to them in the next few days.

Meanwhile, I have tracked down the first ever planet I found: EPIC 201274010.01, a Hot Mini-Neptune orbiting every 13.005090 days at 0.105805 AU with a radius 2.71 times that of Earth and an equilibrium temperature of about 742 K (876 F). The page for it on Exoplanet Explorers can be found HERE.

Edited May 11, 2018 by ProtoJeb21

[ProtoJeb21]

I have no time to do a huge planet candidate reveal, but I will reveal this: three of the planets of EPIC 220221272 have been confirmed. More on this later (unless you’ve been on Planet Hunters over the last 10 days and know exactly what’s going on).

[ProtoJeb21]

Update on EPIC 220221272

Two weeks ago, I started a collaborative research project with Planet Hunters citizen scientist ajamyajax, Exoplanet Explorers citizen scientist Vidar87, and likely more in the future. The goal of this project is to analyze, validate, and publish at least one multi-planet system and likely a few one-planet habitable zone candidate systems. Ajamyajax was the one who first proposed the idea, and I suggested three systems that could be the focus of the study: EPIC 248435473, EPIC 201663913, and EPIC 220221272. The first system is one of my several dozen finds from Campaign 14 and has five planets: two Mini-Neptunes and three small hot Mars-sized planets. However, apparently a few other scientists with far more experience have expressed interest in studying this system, and will likely be validating it within the next few months. The next system, EPIC 201663913, is also a Campaign 14 red dwarf, this time about 40% the size of the Sun. An analysis by citizen scientist zoo3hans (who is one of the co-discoverers of Kepler-86 b) from November 2017 suggested that there could be five Earth-sized and Super-Earth planets orbiting the star, two of which are in the habitable zone. But there's a problem with the system: because of its faintness, and the weakness of the transits, and the fact that there's a second brighter star nearby, it is very complex to analyze (ajamyajax couldn't get any solid results on whether any of the candidates were likely real) and may be a fruitless endeavor.

That leaves just one system left: EPIC 220221272, aka Dagr, the small red dwarf with five tightly packed planet candidates. Over the last two-ish weeks, ajamyajax has been using the VESPA algorithm to validate the candidates while I look for signs of more. His initial VESPA analysis led to the validation of EPIC 220221272.04 (Hermodr), EPIC 220221272.02 (Gerth), and EPIC 220221272.01 (Freyr). The chances that these three candidates are anything other than planets are astronomically tiny - EPIC 220221272.02 has a nearly 1 in 600,000 chance of being a false positive. The best-fit radii of these planets were also determined, coming out to be 0.84 (±0.13) R_⊕, 1.17 (±0.07) R_⊕, and 1.75 (±0.10) R_⊕. EPIC 220221272 was also determined to be slightly hotter and more luminous than previously thought. Using data from the ESA's Gaia spacecraft, the star appears to have a temperature of 3859.78 K and a luminosity 0.0135 times that of the Sun. This, unfortunately, puts EPIC 220221272.01 outside the habitable zone with 2.7 times the stellar flux of Earth, but with a sufficient cloud cover its likely watery surface can be kept at comfortable temperatures (given its size it is likely to be anywhere from 10% to 50% water by mass). 

The other two candidates, EPIC 220221272.03 and EPIC 220221272.05, are giving VESPA a hard time. Their transit signals are relatively "blended in" to the rest of the data for the star, and because of that, VESPA thinks they're something called a Blended Eclipsing Binary. Their transit shapes suggest otherwise, but VESPA is being fooled by the stellar noise corrupting the signals for these two candidates. Both are likely still actual planets and ajamyajax is trying to clean up their transit signals as much as possible so VESPA can accurately determine how likely they are to be planets. Meanwhile, I've found something interesting: there may be THREE more planets around EPIC 220221272. The first is the original EPIC 220221272.06, with an orbital period of about 20.749 days near a 3:2 resonance with EPIC 220221272.01. It gets 55% more sunlight than Earth but is likely too small (0.7 to 0.9 R_⊕) to become a Venus-like planet at its temperature. The second is a new signal found just last month by zoo3hans, orbiting every 25.716 days while getting just 16% more light than Earth. It's designated EPIC 220221272.08, because it was found after this 31.792 day signal now designated EPIC 220221272.07, which gets only 88% as much sunlight as Earth. All three of these candidates could easily be false positives, but EPIC 220221272.06 has the highest chance of being an actual candidate. Ajamyjax began his analysis of the three new candidates two days ago and will likely post his results in the coming days.

This discussion on the study and the EPIC 220221272 system can be found at the ends of the Planet Hunters chat pages linked below:

https://talk.planethunters.org/#/boards/BPH0000007/discussions/DPH0001l3k

https://talk.planethunters.org/#/boards/BPH0000007/discussions/DPH0001fyy

Also, here's a new rendition of the system using the latest results. EPIC 220221272.06 and EPIC 220221272.08 have been given minimum possible radii at 0.70 R_⊕.

Edited June 5, 2018 by ProtoJeb21

[ProtoJeb21]

K2 CAMPAIGN 14 SURVEY RESULTS

It's finally time for the stuff I've been teasing for months now. Starting in December 2017, less than a week before the New Year, I began a survey of K2 Campaign 14 using LcViewer and a new program, LcSignalFinder. The latter allows the user to select multiple light curves for numerous stars and use the Box-Least Squared (BLS) algorithm to search for signals in them. Most of these signals are just stellar noise or variability, some are eclipsing binaries, but a good amount are likely from legitimate planets. K2 Campaign 14 is (so far) the largest campaign with available processed data, with a total of almost 30,000 stars. It took me until March 13th to complete the entire survey, and over a few weeks I continued to analyze the best candidates and systems I found during the survey to put in a Google Document. Those systems will be presented here, and the Google Doc will be linked at the very end, along with the original two Docs where I recorded all of the candidates I came across. In this post, I will be going far more in-depth into these planets than on any of the documents.

EPIC 248527709: A small orange dwarf of spectral type ~K6V with four potential planets orbiting it. Three were found by BLS, and take 0.903, 5.753, and 10.470 days to orbit the parent star. The inner of the three is an Ultra-Short Period (USP) planet about 14% bigger than Earth with a temperature around 1,160 K (1,628 F) while the other two are hot Mini-Neptunes of 2.13 R_⊕ and 1.96 R_⊕ with temperatures of 626 K and 512 K (667 and 462 F). In a post-analysis, I found a transit from a potential long-period planet. Based on the size of the star and the duration of the transit, it appears that this fourth planet is about 2.18 R_⊕ and takes somewhere around 64.308 days to orbit the star. This places it in the inner edge of the habitable zone, with an equilibrium temperature of about 278 K (41 F). However, due to its large size, it is likely a water-dominated planet with no solid surface.

EPIC 248435473: The largest system found so far in Campaign 14, this large M0V red dwarf has a bizarre and compact system of five planets. The inner three are quite small, similar in size to Mars with radii of 0.55 R_⊕, 0.63 R_⊕, and 0.62 R_⊕. The innermost of those three is an USP, taking just 0.659 days (15.8 hours) to complete a single orbit. Tidal forces from the star have likely turned it into a scorched, volcanic version of Mars, possibly similar to the Red Planet in its infancy. The other two "Hot Marses" orbit right on top of each other, with orbital periods of 6.101 and 7.818 days near a 4:3 mean-motion resonance. All three small inner planets have equilibrium temperatures of 1,281 K, 610 K, and 561 K (1,846 F, 638 F, and 550 F). However, the other two planets couldn't be more different. They are warm Mini-Neptunes of 2.64 R_⊕ and 2.47 R_⊕, meaning they are not rocky and likely have thick water and gas envelopes. They orbit quite far from the final Hot Mars but, like planets two and three, are in a close orbital resonance. The outer two planets orbit every 14.705 and 19.478 days, very close to a 4:3 resonance as well, with temperatures of 455 K and 414 K (359 F and 286 F). This was one of the systems under consideration for that joint Planet Hunters/Exoplanet Explorers study I mentioned a few days ago, but Andrew Vanderberg has expressed interest in doing an analysis of the system as well, so it's best to let the professionals handle this one.

EPIC 248463350: A very Sun-like star with two hot transiting planets, one Super-Earth/Mini-Neptune and one Hot Neptune. The inner planet is 1.96 R_⊕ and orbits every 6.40 days with a temperature of 1,050 K (1,430 F). It is likely to have some sort of gas envelope around 0.1-1% of the planet's total mass, either as water vapor or hydrogen. The second, much larger planet, is even bigger than Neptune at 4.73 R_⊕. It has a year lasting 18.804 days and a temperature of 733 K (860 F). Despite being a rather boring system, it's a very good target for validation, as the signals of the two planets are quite prominent. In addition, the two candidates are almost exactly in a 3:1 resonance, meaning that they could case visible Transit Timing Variations (TTVs).

EPIC 248545986: A red dwarf with three small transiting planets, all likely to be rocky. It was recently validated HERE, so there's not much to talk about.

EPIC 248558190: Two planet candidates were found around this star. Even though on ExoFOP it's been given parameters suggest that it's an M-dwarf, the J/H/K magnitudes of the star are more compatible with a small orange dwarf. The first planet appears to be a 1.25 R_⊕ Super-Earth (although it's likely larger) orbiting every 8.204 days. Its temperature is over 430 K. The second planet was found by a single transit event lasting 6.37 hours, and appears to be from a Super-Earth/Mini-Neptune likely orbiting in or near the system's habitable zone, or possibly even further out.

EPIC 248651022: This is a very hostile system that's very close to being validated. The Sun-like star EPIC 248651022 has three planet candidates - two Mini-Neptunes and one Hot Neptune, all orbiting in less than a week. All of them were analyzed by ajamyajax a few months ago. The first planet is 2.14 (±0.05) R_⊕ and takes a mere 1.49 days to orbit, and as a result is blowtorched at a temperature of 1,793 K (2,768 F), almost hot enough to melt iron. It therefore falls into the category of planets know as COSSNs (Closely Orbiting Scorched Sub-Neptunes) and is likely a molten rocky Mega-Earth. Planet c is larger at 2.44 R_⊕ and is also cooler at 1,374 K (2,014 F), taking 3.302 days to orbit the star. It is too large and not hot enough to be stripped of its volatile envelope like planet b. The first two planets were found to have FPPs low enough to consider them validated, but the third might be a background eclipsing binary. If a real planet, it's by far the largest at 3.95 R_⊕, almost the size of Neptune, and orbits every 5.116 days with a temperature of 1,187 K (1,677 F). A group of scientists have imaged the star with the Keck telescope back in March, so it looks like it is in the process of being validated right now.

EPIC 248868569: This is one of my greatest finds ever. At first, it appeared to be just a normal eclipsing binary, with two red dwarfs less than a quarter the size of the Sun each circling each other every 17.461 days in a moderately eccentric (e=0.1505) orbit. However, once highlighting the primary and secondary eclipses, there was one huge dip that remained. A quick analysis revealed this was likely from a Super-Neptune planet, around 5.18 R_⊕, taking no less than 80 days to orbit the binary pair. I had found my first circumbinary candidate planet! I came across it on Valentine's Day, the same day a one other very intriguing find I will discuss later. Because of how special this discovery was, I decided to give this planet an unofficial nickname, and I finally settled on Montross, which is possibly the only circumbinary gas giant in all of the new Star Wars canon so far and appeared in the series Star Wars Rebels. This system was already one of a kind, but almost a month later, on March 13th, it became even more amazing. While doing a re-analysis of it after finishing up my Campaign 14 survey, I spotted a second potential long-period planet transit, this one from a 1.40 R_⊕ Super-Earth orbiting even further out than Montross. I decided to continue the Rebels planet name idea, which was a bit of challenge, because Rebels doesn't have many notable ice worlds like the one I had just found. There were Nixus and Killun-71 A, but neither fit. The former is a tiny dead water ice ball, and the latter is part of a binary planet system. Then I realized there was one more named ice planet in Rebels: Krownest (kinda pronounced like Cronus), a Mandalorian controlled planet in the Outer Rim. Not the most elegant name, but far better than having to constantly call this thing EPIC 248865869 AB c. With some help from ajamyajax, the orbital periods of Montross and Krownest were revealed. It turns out that their actual orbital periods depend on which star they transited. For Montross, its year is either 243.29614 or 475.16407 days, which would put it at 0.601 or 0.910 AU (the combined mass of the stars is about 0.49x Sun) giving it a temperature of 110 K (-262 F) or 90 K (-298 F). That's cold enough to allow liquid methane on any of its moons, if it has large moons like Titan, but if you think that's cold then Krownest will be an absolute shock. Its orbit period is either 3.689 or 7.206 YEARS long, which could make it the longest-period transiting planet ever discovered. That puts it at a whopping 1.882 to 2.941 AU away from the binary pair, and considering how the twin suns have a combined luminosity of only about 1.5% that of the Sun, Krownest is beyond freezing. Its temperature is 62 K (-348 F) at the max and 50 K (-370 F) at the minimum. This is cold enough to freeze methane and even nitrogen and oxygen, depending on what the planet's actual temperature is. If it has a thick atmosphere, Krownest could be an orange Super-Pluto with oceans of liquid nitrogen and/or oxygen. There's no other planet like it, and it remains by far one of my absolute favorite finds.

EPIC 248731669: Another system that was a potential target for that PH/EE study. ExoFOP says this is a red dwarf around a third the size of the Sun with a temperature comparable to an M2V dwarf, but its J/H/K magnitude values suggest a larger M0V dwarf. Its three-planet system is quite similar to K2-155...at least, back when it was still known as EPIC 210897587 - a hot close Earth-sized planet, a large potential Super-Venus further out, and a habitable zone Super-Earth with a size in between that of the inner two planets. Like K2-155, the star and planets are probably larger and hotter than originally estimated. The three planets were found to be 1.04 R_⊕, 1.49 R_⊕, and 1.33 R_⊕ with equilibrium temperatures of 571 K, 326 K, and 281 K (568 F, 127 F, and 46 F) for the ExoFOP parameters. They orbit the host star every 2.624, 14.047, and 21.963 days near a 20:4:3 resonance chain. The outermost planet, EPIC 248731169 d, may be similar to K2-155d, depending on the exact size of its host star.

EPIC 248740571: Yet another three-planet system, this is a mid-sized orange dwarf with three "triplet" Mini-Neptune candidates. They're all around the same sizes at 2.52 R_⊕, 2.56 R_⊕, and 2.47 R_⊕ with orbital periods of 9.030, 16.109, and 33.363 days. All are uncomfortably warm with equilibrium temperatures of 685 K, 565 K, and 443 K (773 F, 557 F, and 338 F).

 

I'm running out of time while I'm writing this, so the second part with the remaining candidates, planet renditions, and pdf documents full of planets will be posted tomorrow.

[Spaceception]

Always enjoy reading these, Krownest would be really cool to study, and it'd be a treat to find another world with exotic oceans.

[ProtoJeb21]

11 minutes ago, Spaceception said:

Always enjoy reading these, Krownest would be really cool to study, and it'd be a treat to find another world with exotic oceans.

 Definitely cool to study, but also extremely hard to do so. Remember, it’s minimum orbital period is nearly 3.7 years long. It’s likely we will never see it transit again, and it’s too far from the stars to determine its mass. Bummer. 

[ProtoJeb21]

I think it's pretty obvious that I never get to things on the Forum on the day I plan to do them. Sorry. Part 2 will be out...eventually. I'm working on a writing assignment right now and also trying to take care of literally dozens of hatching Tent Moths, so my hands are pretty full. Maybe tomorrow or Friday or Saturday I'll get to it.

[Scotius]

Now we just need a functional FTL drive to start colonising and mining And to think i remember the times when some astronomers (pessimistic ones) theorised that number of planetary systems in our Galaxy was at low hundreds. I'm so glad they were proved wrong

[Hypercosmic]

On 6/14/2018 at 2:29 PM, Scotius said:

Now we just need a functional FTL drive to start colonising and mining And to think i remember the times when some astronomers (pessimistic ones) theorised that number of planetary systems in our Galaxy was at low hundreds. I'm so glad they were proved wrong

That sounds like it's from the days when the hypothesis that planets form after a close encounter between the Sun and another star was still around.

[Scotius]

33 minutes ago, Hypercosmic said:

That sounds like it's from the days when the hypothesis that planets form after a close encounter between the Sun and another star was still around.

Yup. Taken straight from thick, respectable astronomy books in public library of my town Which, granted - weren't probably super up-to-date. But it still would take several years before prof. Wolszczan's team found the first proven extrasolar planetary system - around a pulsar of all places.

[ProtoJeb21]

One of my C14 systems is now confirmed and...wow, it is weird. 

https://arxiv.org/pdf/1806.08368.pdf

[The Minmus Derp]

ERMAGERD!!!! It’s because of you, @ProtoJeb21, that i will start on Plernert Hernters.

(misspell for the LOLz)