TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Huh! I had no idea you could get spin-orbit resonances with such low eccentricities!

Thanks for posting that paper, that'll come in pretty useful for worldbuilding-type stuff.

Playing around with the formulae in here and the maximum triaxiality formulae there, if I set the eccentricities to the maximum values I get probabilities of up to ~8% for capture into the 3:2 resonance for some of the TRAPPIST-1 planets using the bare rock triaxiality. However these eccentricities are likely quite a lot higher than the true system, which results in decreasing probability of resonance capture.

http://archive.stsci.edu/archive_news/2017/03-Mar/index.html#article1

Raw observational data from K2 Campaign 12, featuring the TRAPPIST-1 exoplanet system, will be available for download from MAST on Tuesday, March 7th

K2 data released.

NASA press release
Data on MAST

Possibly 9 planets around Trappist 1 ? It would be very interesting indeed

EPIC 200164267, P=1.5108 days, starting at BKJD 2906.52, duration 1.5 hours, depth 0.0078 (planet b) 
EPIC 200164267, P=2.4218 days, starting at BKJD 2907.53, duration 1.5 hours, depth 0.0055 (planet c) 
EPIC 200164267, P=4.0496 days, starting at BKJD 2905.98, duration 1.5 hours, depth 0.0054 (planet d) 
EPIC 200164267, P=6.0996 days, starting at BKJD 2906.66, duration 2.5 hours, depth 0.0034 (planet e) 
EPIC 200164267, P=9.2066 days, starting at BKJD 2912.02, duration 2.5 hours, depth 0.0081 (planet f) 
EPIC 200164267, P=12.352 days, starting at BKJD 2906.49, duration 2.5 hours, depth 0.0070 (planet g) 
EPIC 200164267, P=16.550 days, starting at BKJD 2906.83, duration 3,5 hours, depth 0.0072 (planet X) 
EPIC 200164267, P=19.974 days, starting at BKJD 2923.70, duration 3.5 hours, depth 0.0076 (planet h) 
EPIC 200164267, P=26.740 days, starting at BKJD 2923.19, duration 1.5 hours, depth 0.0099 (planet Y),

What is the source for that?

It's in one of the comments on the MAST page. If that ends up being confirmed, nine planets would make it the highest number of any known planetary system, pretty impressive for such a small star.

According to our planet hunters talk actually we do not know whether tentative planet h detected by Spitzer has 20 days period it can have two different periods maybe even single transit of more distant planet

I'm a bit confused as to why the "X" planet would not have shown up in the Spitzer LC, unless it transited simultaneously with the "h" planet?

Maybe x transited during glitch or gaps when spitzer transmitted data

??

Led_Zep wrote:

??

Light curves for the b, c, d and e planets.

Bit different values for radii for b,c,d than in nature paper equalizing densities b and c. I wonder is better to have 4 times more data from k2 or from spitzer?

Tentative planet h has different period than 20 days  as I guessed. Indeed it is 32.6 days. One of our planet hunter volunteer found 2 additional transits of planet h in K2 data.

"Appearing in 24 hours on arXiv! A first look at #TRAPPIST1h resulting from a heroic 65 hour effort led by @rodluger! Excited to share more!"
https://twitter.com/ethan_kruse/status/841092095448305665

Shot of planet h ?

A terrestrial-sized exoplanet at the snow line of TRAPPIST-1
https://arxiv.org/abs/1703.04166

Quote :

The TRAPPIST-1 system is the first transiting planet system found orbiting an ultra-cool dwarf star. At least seven planets similar to Earth in radius and in mass were previously found to transit this host star. Subsequently, TRAPPIST-1 was observed as part of the K2 mission and, with these new data, we report the measurement of an 18.764 d orbital period for the outermost planet, TRAPPIST-1h, which was unconstrained until now. This value matches our theoretical expectations based on Laplace relations and places TRAPPIST-1h as the seventh member of a complex chain, with three-body resonances linking every member. We find that TRAPPIST-1h has a radius of 0.715 Earth radii and an equilibrium temperature of 169 K, placing it at the snow line. We have also measured the rotational period of the star at 3.3 d and detected a number of flares consistent with an active, middle-aged, late M dwarf.

The star : an age in the range 3-8 Gyr ! (0.5 previously)
Near the end of the K2 campaign, a very energetic flare erupted
no detected additional planets in the system

It seems that one transit of planet_h is hidden in a flare, and one is inside a transit of planet_b I m not really convinced

Led_Zep wrote:

The star : an age in the range 3-8 Gyr ! (0.5 previously)
Near the end of the K2 campaign, a very energetic flare erupted
no detected additional planets in the system

There goes that system's habitability.

PlutonianEmpire wrote:

There goes that system's habitability.

Isn't that a little too premature an announcement to make in that we know nothing yet about the atmospheres and gravities of any of the planets in the system? Besides, even accounting for possible thin atmospheres and weak gravities on all of the planets, we know zilch about any ocean/s on any of the worlds in the system, no?

Also am I correct to say that as we know not if any of the planets in the TRAPPIST-1 have ocean/s, we cannot yet rule out the possibility of life having survived perhaps even prospered due to the protection offered by the oceanic cover, yes? No?

Same applies to possible subterranean life also, no ?