1st targets for JWST selected

[Spaceception]

Among these targets is NEO, Trojans, many observations of the gas giants and their moons, and a heap of science for exoplanet atmospheres, and other stars.

And one of them is TRAPPIST-1e!!

Quote

TRAPPIST-1e. We will probe this planet in transmission using the NIRSpec Prism mode, which provides low-resolution spectra in the 0.6-5.3 micron range. Probing the atmospheres of small exoplanets require multiple transit/eclipse observations to build sufficient precision to detect atmospheric features. Here we plan for five transit observations of this target with the NIRSpec Prism. The orbital period of TRAPPIST-1e is ~6 days, so ample observing opportunities will exist for this planet. MOUNTAIN_1111-1115

 

https://jwst-docs.stsci.edu/display/JSP/JWST+GTO+Observation+Specifications#JWSTGTOObservationSpecifications-ObservationsofSolarSystemObjects

[cubinator]

Cool! Can't wait to see all the amazing science we'll get from this telescope.

[radonek]

I just wonder how long will JWST work without all the maintenance HST got during its life.

[HebaruSan]

7 minutes ago, radonek said:

I just wonder how long will JWST work without all the maintenance HST got during its life.

For reference, there were 5 such missions over 16 years, focused on installing new instruments and replacement of: worn out components, failed gyros (in one case preventing Hubble from functioning), solar panels, batteries, computers, sensors, and insulation.

• https://www.nasa.gov/mission_pages/hubble/servicing/index.html

I looked that up because I only remembered hearing about the famous first one. Since Kepler also had failures in its stabilization systems, I wonder whether the reliability of the ones planned for JWST has been improved at all.

[radonek]

https://jwst.nasa.gov/faq_scientists.html#gyros

 

 

 

[StupidAndy]

so Trappist-1 is only 39 light years away right?

that's well inside of Hubble's parameters, why can't they just photograph it with Hubble?

probably the Stars light is affecting it

did I solve my own question?

[ProtoJeb21]

Don't forget the other targets: GJ 3470b, Gliese 1132b (Aine), Wasp-17b, HD 189733b (that glass rain planet), several other hot gas/ice giants, and even the other three habitable zone planets of Trappist-1!!!

[Cabbink]

Sweet!

[HebaruSan]

20 minutes ago, StupidAndy said:

why can't they just photograph it with Hubble?

Good question. HST observes in near ultraviolet, visible, and near infrared light (https://en.wikipedia.org/wiki/Hubble_Space_Telescope).

Near infrared is 0.75–1.4 microns (https://en.wikipedia.org/wiki/Infrared), and visible and ultraviolet are smaller (down to 0.4 microns, https://en.wikipedia.org/wiki/Ultraviolet). So Hubble is near its limits around 1.4 microns and up.

Whereas with JST, we'll get (from @Spaceception's source)...

Quote

low-resolution spectra in the 0.6-5.3 micron range.

... so it'll see further into the infrared spectrum than Hubble can. That was supposed to be a particular advantage of JWST for exoplanet research, but I don't remember the reason why.

Edited June 19, 2017 by HebaruSan

[Starman4308]

22 minutes ago, HebaruSan said:

... so it'll see further into the infrared spectrum than Hubble can. That was supposed to be a particular advantage of JWST for exoplanet research, but I don't remember the reason why.

I don't know why that in the general case, but in the specific case of TRAPPIST: don't red dwarfs emit primarily in infrared? You'd probably get the best signal in the longer wavelengths.

[Green Baron]

The information about the motivation, purpose and instrumentation of and for the jwst is on the jwst web site: https://jwst.nasa.gov/

Exoplanets are not jwst's main purpose, though new questions will surely come up with it's discoveries. Exoplanets are better done in the future with big ground based telescopes with 30 and more meters diameter.

8 hours ago, StupidAndy said:

so Trappist-1 is only 39 light years away right?

that's well inside of Hubble's parameters, why can't they just photograph it with Hubble?

probably the Stars light is affecting it

did I solve my own question?

No telescope can actually take a photograph of an exoplanet (if it's not a giant Jupiter far from its star in planetary disc perpendicular towards us).

That star flickers, and the period and intensity of the flickering *alone* is what lead to the planet discoveries of the Trappist-family.

Edited June 20, 2017 by Green Baron

[magnemoe]

12 hours ago, radonek said:

https://jwst.nasa.gov/faq_scientists.html#gyros

This sounds more like an gyro for navigation than an reaction wheel. 
The gyro is used to monitor your bearing and rotation, the reaction wheels are used for rotating you without using reaction mass, this require an high momentum to be effective. 
Now in zero g magnetic bearing should be very effective as in not wear out as its no wear and tear, still its an moving part. 

[Green Baron]

The article is a little misleading. What they call a gyroscope (Hemispherical Resonator Gyroscope) is only for measuring the bearing and it does so electrostatically. It has no moving parts and is, if manufactured thoroughly, very accurate and long lived.

For actual aiming jwst of course must use a reaction mass in the form of moving wheels. Thrusters aren't applicable for that purpose, they are for long term station keeping around the lagrange point.

Magnetic bearing isn't applicable out there, earth's magnetic field is too weak and a little "biased" towards earth :-), the sun's is too variable.

Edited June 20, 2017 by Green Baron

[kerbiloid]

They should first have a look at KIC 8462852.
Maybe after that, all other aims were no more required.

[YNM]

JWST will operate mainly in IR because...

 

 

... they aren't available on ground. Keck can easily surpass HST's ability using speckle interferometry (lucky imaging); Even bigger visible telescopes are now in comission; hence the point of a visible telescope in space is now moot. Combined with the fact that IR and NIR are now the main spectrum in astronomy (lots of reasons, dust-occulted objects will be visible in IR, redshifted object glows in IR, small bodies glows in IR better than reflecting visible light, etc.), they decided for the whole thing to be in IR/NIR. (Probably. Also probably because IR telescopes are bad in visible, so choose one, not both.)

UV are also interesting, but they are only useful in short range (within solar system or even close to the object itself), or will only be emitted in high-energy bursts, which will then be followed by other parts of the spectrum. You don't need that much resolution for the last one. Same story with X-ray and γ-ray.

 

How long will it lasts ? Well, things in L points generally lasts in useful mode as long as their propellant lasts. Fingers cross it won't need much more than what the planners planned so the mission can be extended.

Edited June 21, 2017 by YNM

[_Augustus_]

Calling it now. JWST will find evidence of life on TRAPPIST-1e.

Edited June 27, 2017 by _Augustus_

[Mitchz95]

22 hours ago, _Augustus_ said:

Calling it now. JWST will find evidence of life on TRAPPIST-1e.

Isn't that system less than a billion years old? Not a lot of time for life to evolve.

EDIT: According to Wikipedia, actually 3-8 billion years. Not sure where I read <1...

Edited June 28, 2017 by Mitchz95

[Spaceception]

8 hours ago, Mitchz95 said:

Isn't that system less than a billion years old? Not a lot of time for life to evolve.

EDIT: According to Wikipedia, actually 3-8 billion years. Not sure where I read <1...

At first they thought it was less than a billion years old, but they have better estimates now.

And it took less than a billion, perhaps around half a billion years after the earth formed to have life. 

[Green Baron]

11 minutes ago, Spaceception said:

 

And it took less than a billion, perhaps around half a billion years after the earth formed to have life. 

Yes, that is true, the transition from non-life to life was put ever more forward.

New discussion on the topic here from an energy source point of view.

In the past two or three decades, since we started to think seriously :-) about 42, the overall picture points to an easy beginning and long hard way with a lot of coincidences, chances and luck that led to today's biosphere. 3 to 8 billion years really say little, even if everything went as fine as possible.

Imo