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

[ProtoJeb21]

EPIC 210693462 b has been confirmed as K2-288 Bb!

https://www.jpl.nasa.gov/news/news.php?feature=7313

[Racescort666]

3 hours ago, ProtoJeb21 said:

EPIC 210693462 b has been confirmed as K2-288 Bb!

https://www.jpl.nasa.gov/news/news.php?feature=7313

I just read that and immediately thought of this thread.

[Ozymandias_the_Goat]

On 1/7/2019 at 5:14 PM, Racescort666 said:

I just read that and immediately thought of this thread.

I did too, although I do think of this thread any time that exoplanetology comes up. It’s incredible how effective citizen science is; the human’s inherent skill to recognize patterns is astonishing.

[ILoveStars]

Anyone heard of HD 21749 b? Suspecting it's a water world.

https://exoplanets.nasa.gov/news/1542/nasas-tess-rounds-up-its-first-planets-snares-far-flung-supernovae/

 

HD 21749 b is on here.

Edited January 11, 2019 by ILoveStars

[ILoveStars]

or maybe somefink like Gliesd 436b.

 

Also, anyone heard of the candidate super-neptune GJ 143 b?

[ProtoJeb21]

Sorry I didn’t do a dedicated post about K2-288Bb, and that I haven’t been around very often. I’ve been trying to sort out some things about K2-288Bb and find some more planets, while also analyzing a few TESS exoplanet candidates and preparing for other things that I’ll post about once they’re finished. Since it’s been a month now, I will finally make my K2-288Bb overview post and present some very interesting finds from Planet Hunters TESS, including multiple using the radial velocity technique. Stay tuned!

[ILoveStars]

Has LHS 3844 b's mass been measured yet? If it has, then tonight I'm hopping on US2 to work out its density, and maybe its composition.

I'll still not really be expecting a super-mercury, though.

[ProtoJeb21]

2 hours ago, ILoveStars said:

Has LHS 3844 b's mass been measured yet? If it has, then tonight I'm hopping on US2 to work out its density, and maybe its composition.

I'll still not really be expecting a super-mercury, though.

I don’t think so. At least, nothing has been published yet. It’ll probably take several more months at least before we get something. 

[ILoveStars]

16 hours ago, ProtoJeb21 said:

I don’t think so. At least, nothing has been published yet. It’ll probably take several more months at least before we get something. 

aww.

[ILoveStars]

i wonder when TESS is gonna discover another rocky planet.

 

Anyway, I measured HD 23472 b's density and looks like this new TESS rocky planet (HD 23472 b) is the new rocky planet godzilla.

Mass: Greater than neptune. (about 18 earths)

Radius: 1.87 earths

Density: about 3 times that of earth.

i did that in US2.

It's very useful.

 

Well, I'm not sure if Kepler-10 c is more massive.  It's only 7 earth masses, but it's bigger than HD 23472 b. So it could be just ANOTHER kepler-22 b, instead of the gargantuan rock everyone thinks it is. So here is the actual rocky planet godzilla: HD 23472 b.

 

Now that I think about it, Kepler-10 c could just be a gas dwarf! It's *only* 3.15g/cm3, so without all that 'hydrostatic' pressure, it might not even be as dense as water! Yeah, so Kepler-10 c is probably not a rocky planet, and HD 23472 b probably is.

Edited March 6, 2019 by ILoveStars

[ProtoJeb21]

Either later tonight or tomorrow, I will make my post on K2-288 Bb, as well as several new TESS systems I’ve helped characterize. These have been confirmed via radial velocity and transit data, so decent estimates on their compositions are available. These will include an update on HD 48611 b and the HD 23472 system, as well as a few RV-only systems found by a citizen scientist on Planet Hunters TESS. 

EDIT: scratch that, I just realized my schedule is literally packed to the max until Saturday night. I may be able to get one system out tonight and save the rest (including Space Engine renditions of them) for this weekend. 

Edited February 14, 2019 by ProtoJeb21

[ProtoJeb21]

HD 48611 b

I feel like it’s best to start off with a familiar planet to introduce the methodology used for all the systems I will (eventually) cover. A citizen scientist from Planet Hunters TESS, EEdiscoverer, is able to use a program called the Systemic Console to analyze archived HARPS radial velocity data to search for planets. It’s rather accurate and can provide some good estimates for the masses and eccentricities of the planets it’s able to detect. It is also very helpful for confirming TESS candidates around stars with old RV data that has been long forgotten. I will get to some of the RV systems EED has found this weekend, but for now I’ll be covering the TESS candidates that he managed to confirm. While he finds the masses of the planets, I use the latest TESS data from the Mikulski Archive for Space Telescopes (MAST) and LcViewer to get a better estimate for the planet’s radius. It turns out that many of my radius estimates over the last two years have probably been slightly over-estimated due to what’s known as the limb-darkening effect. In summary, the disk of a star is always brighter in the middle and dimmer at the outer edge, and this influences the estimate for a transiting planet’s radius, decreasing it slightly most of the time, unless it has an orbit that just skims the disk of the star. I took this effect into account when analyzing these TESS candidates. 

With the procedure finally out of the way, it’s time to talk about what we found. My radius results varied depending on how many data points I allowed to be generated in the light curve. 30 per hour often started to “blend in” the transits, so I later went with 6 per hour. Taking into account limb darkening and the uncertainty of the planet’s transit duration, I found the radius of HD 48611 b to be about 1.67 (+/-0.10) R_Earth. This is within the Fulton Gap, a range of planetary radii from 1.6 to 2.0 R_Earth where planets are less common because they’re transitioning from rocky Super-Earths to puffy Mini-Neptunes. Therefore, HD 48611 b should have a mass compatible with a rocky composition and a thin water layer, right? Nope. The Systemic Console’s best fit for the RV data of HD 48611 was a planet 8.39 times the mass of Earth with an orbital eccentricity of 0.2791. That puts the planet’s density at a hefty 9.9 g/cm^3, and a surface gravity of almost exactly 3 gees. 

The results provided by EEdiscovere, along with my transit analysis, suggest HD 48611 b is a rare high-density Fulton Gap planet compatible with a relatively iron-rich composition and NO significant volatile layer (hydrogen, helium, water vapor, methane, or other heavier gases). The planet’s core could take up 45-60% of its entire mass — that’s an iron core as much as five times the mass of Earth! This is at odds with current theories about the Super-Earth/Mini-Neptune transition. So, why is HD 48611 b so dense? One may first assume a giant impact like Mercury or the recently characterized Kepler-107c (which is even bigger at almost ten Earth masses), but the answer is much simpler: the star is metal-poor. HD 48611 contains only about 43% as much metals, or any element heavier than hydrogen or helium, as our own Sun. While at first the formation of a giant rocky planet around such a host seems unlikely, it’s the complete opposite, because forming planets around metal-poor stars take too long to get large enough to accumulate thick volatile layers. By the time most have reached this size limit, the original hydrogen disk has been blown away by stellar radiation, leaving mainly heavier materials left for the new planets to feed on. Also, since no other planets have been found, and since it has an unusually eccentric orbit, it can be assumed that HD 48611 b consumed all the forming planets in the inner system when it was young, allowing for it to accumulate such a high quality of rock and iron. 

But just when this planet was figured out, the Universe decided it wasn’t done being weird. It turned out HD 48611 b was just the tip of the iceberg for unusual density TESS planets, and some would be even more extreme with an even more violent past. I promise that I will present these systems as soon as I have an hour or two to do so. 

Edited February 14, 2019 by ProtoJeb21
Typos

[ProtoJeb21]

My post on the new RV/TESS planets is going to have to wait, as our analyses on several of them are taking much longer than I anticipated.

[ILoveStars]

When I first read about TOI-150, i thought it was HD 23472.

HD 23472 b is my fav TESS planet.

[ILoveStars]

Some new exoplanets discovered:

 

Proxima c: A super-cold super-earth orbiting Proxima centauri. Probable temperature: -235 C? (You probably know how happy I am to hear about this, although it's unconfirmed.)

HD 21749 c: That unconfirmed little rock orbiting HD 21749 is finally confirmed, and it's the smallest confirmed TESS planet yet! 

Kepler-47 d: This, for me, messes up the whole Kepler-47 system! It's a Saturn-sized planet orbiting between b and c! This just doesn't make much sense for me! (It doesn't look very stable)

Edited April 17, 2019 by ILoveStars

[Hypercosmic]

2 hours ago, ILoveStars said:

Some new exoplanets discovered:

 

Proxima c: A super-cold super-earth orbiting Proxima centauri. Probable temperature: -235 C? (You probably know how happy I am to hear about this, although it's unconfirmed.)

HD 21749 c: That unconfirmed little rock orbiting HD 21749 is finally confirmed, and it's the smallest confirmed TESS planet yet! 

Kepler-47 d: This, for me, messes up the whole Kepler-47 system! It's a Saturn-sized planet orbiting between b and c! This just doesn't make much sense for me! (It doesn't look very stable)

Proxima c is a candidate.

Apparently the Kepler-47 system is stable.

[ILoveStars]

On 4/17/2019 at 9:04 AM, Hypercosmic said:

Proxima c is a candidate.

Apparently the Kepler-47 system is stable.

a. I know.

b. ok.