K2 News and Results

I'm part of an association for popular science in France named Planète-Sciences and I am able to pilot the 600mm TJMS telescope of our observatory next to Paris (but havent touched it for half a year ). I received a mail and I'm very proud that amateur astronomers at our observatory have validated a candidate from K2 mission.

The observation was made by Olivier Désormières, jean Michel Vienney and Bruno Dauchet and mandated by Alexandre Santerne. In the mail I received, the star is TYC 1818-1428-1 and the exoplanet is named K2 (9792).

Félicitations !!!!!
C'est quel observatoire ?

C'est le centre d'astronomie Jean-Marc Salomon, situé à la base de loisir de Buthiers (we shouldnt talk french here^^)

Mais, je comprendre (un peu)! "une foule de trois", non? 

Looking at things on planet hunters, this looks like a Hot Jupiter around an early-K dwarf (EPIC 211089792). I remember avoiding looking at it as the target is a close, probably physical binary, so I imagine that's what the ground-based observations were for.

Anyway, congratulations!!

EPIC210957318b and EPIC212110888b: two inflated hot-Jupiters around Solar-type stars
http://arxiv.org/abs/1601.07635

EPIC211089792 b: an aligned and inflated hot jupiter in a young visual binary
http://arxiv.org/abs/1601.07680

Confirmation of Two Hot Jupiters from K2 Campaign 4
http://arxiv.org/abs/1601.07844

Stalker wrote:I'm part of an association for popular science in France named Planète-Sciences and I am able to pilot the 600mm TJMS telescope of our observatory next to Paris (but havent touched it for half a year ). I received a mail and I'm very proud that amateur astronomers at our observatory have validated a candidate from K2 mission.

The observation was made by Olivier Désormières, jean Michel Vienney and Bruno Dauchet and mandated by Alexandre Santerne. In the mail I received, the star is TYC 1818-1428-1 and the exoplanet is named K2 (9792).

http://arxiv.org/abs/1601.07680

EPIC211089792 b: an aligned and inflated hot jupiter in a young visual binary

Congratulations!

Seconded! Congratulations, Stalker!

Sadly i didnt do anything, the congratulations goes to the cited astronomers.

The K2-ESPRINT Project IV: A Hot Jupiter in a Prograde Orbit with a Possible Stellar Companion
http://arxiv.org/abs/1602.00638

We report on the detection and early characterization of a hot Jupiter in a 3-day orbit around EPIC 212110888, a metal-rich F-type star located in the K2 Cycle 5 field. Our follow-up campaign involves precise radial velocity (RV) measurements and high-contrast imaging using multiple facilities. The absence of a bright nearby source in our high-contrast data suggests that the transit-like signals are not due to light variations from such a contaminant star. Our intensive RV measurements show that EPIC 212110888b has a mass of 1.726±0.085MJ, confirming its status as a planet. We also detect the Rossiter-McLaughlin effect for EPIC 212110888b and show that the system has a good spin-orbit alignment (λ=4+11−10 degrees). High-contrast images obtained by the HiCIAO camera on the Subaru 8.2-m telescope reveal a faint companion candidate (ΔmH=6.19±0.11) at a separation of $\sim 0\farcs36$. Follow-up observations are needed to confirm that the companion candidate is physically associated with EPIC 212110888. EPIC 212110888b appears to be an example of a typical ``hot Jupiter,' albeit one which can be precisely characterized using a combination of K2 photometry and ground-based follow-up.

Mc Donald Obs. press release about K2-25b (EPIC 210490365) :

http://mcdonaldobservatory.org/news/releases/20160224

EPIC 206318379 = K2-28
http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=k2-28+b&type=CONFIRMED_PLANET

http://arxiv.org/abs/1603.01721

An independent discovery of two hot Jupiters from the K2 mission

We report the discovery of two hot Jupiters using photometry from Campaigns 4 and 5 of the two-wheeled Kepler (K2) mission. EPIC210957318b has a mass of 0.65±0.14MJ, a radius of 1.070±0.018RJ and transits its G dwarf (Teff=5675±50 K), slightly metal rich ([Fe/H]=+0.06±0.04 dex) host star in a 4.1 days circular orbit. EPIC212110888b has a mass of 1.63±0.12MJ, a radius of 1.38±0.014RJ and has an orbital period of 3.0 days in which it orbits a late F dwarf (Teff=6149±55 K) solar metallicity star. Both planets were validated probabilistically and confirmed via precision radial velocity (RV) measurements. They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via detailed follow-up observations.

http://www.nasa.gov/feature/ames/nasas-k2-mission-the-kepler-space-telescopes-second-chance-to-shine

Press release :

NASA's K2 mission: The Kepler Space Telescope's Second Chance to Shine

Adams, Jackson & Endl "Ultra Short Period Planets in K2: SuPerPiG Results for Campaigns 0-5"
http://arxiv.org/abs/1603.06488

Possible hints that the K2 planet population may have different characteristics compared to the Kepler population.

Led_Zep wrote:

Stalker wrote:I'm part of an association for popular science in France named Planète-Sciences and I am able to pilot the 600mm TJMS telescope of our observatory next to Paris (but havent touched it for half a year ). I received a mail and I'm very proud that amateur astronomers at our observatory have validated a candidate from K2 mission.

The observation was made by Olivier Désormières, jean Michel Vienney and Bruno Dauchet and mandated by Alexandre Santerne. In the mail I received, the star is TYC 1818-1428-1 and the exoplanet is named K2 (9792).

http://arxiv.org/abs/1601.07680

EPIC211089792 b: an aligned and inflated hot jupiter in a young visual binary

EPIC 9792 is now K2-29b/WASP 152b. Soon in the Astrophysical Journal.

Mass determinations from RV and TTV for the K2-19 system:

Nespral et al. "Mass determination of K2-19b and K2-19c from radial velocities and transit timing variations"
http://arxiv.org/abs/1604.01265

Fits with an emerging trend that TTV-derived masses are systematically lower than RV-derived masses.

Considering the sparsity of TTV measurements that are supported by RV measurements, this work certainly implies that mass determinations from TTV measurements continue to have to be taken with caution, until a better understanding about the causes that may generate any systematics between RV and TTV derived planet masses is achieved.

Doppler Monitoring of five K2 Transiting Planetary Systems
http://arxiv.org/abs/1604.01413

Not often that you see a run-on abstract.

There's quite a large discrepancy for the K2-19 results between these papers, which needs some inspection. Looking at the masses:

	mb (M⊕)	mc (M⊕)
Nespral et al.	59.5 ± 9.3	9.7 ± 3.0
Dai et al.	28.5 ± 5.2	25.6 ± 7.1

(errors have been averaged to symmetry for simplicity)

These disagree with each other by a factor of ~2 in opposite directions, which is quite severe.

I cannot currently do any RV modelling, so for the time being I can only conjecture the cause of this issue. Nespral et al. do not consider the effects of stellar rotational activity, which Dai et al. observe as their most significant signal; they also barely consider planet c in the RVs, which may not be appropriate. Though Dai et al. do treat for the rotational signal, they note that the way in which they do it (cutting the dataset into sections) may not be valid considering the modest ratio between P_c and P_rot, which I agree with. This may lead to an overestimate of the semi-amplitude for c.

Barros et al. (2015) give the ratio m_c/m_b = 0.42 ± 0.12 based on TTVs, which should be accurate as long as gravity works as we think it does. For the above results, m_c/m_b = 0.16 ^+0.09_-0.07 and 0.90 ^+0.39_-0.35 , respectively. The Nespral et al. value is clearly too small, while the Dai et al. value is too large, to lower precision. This should probably be interpreted as an overestimation of m_b by Nespral et al., and an overestimation of m_c by Dai et al.

As Dai et al.'s RV dataset is much larger and more precise than Nespral et al.'s, I would suggest that their result is probably the truer of the two. I expect a better result could be reached with improved modelling.

The discrepancy is even worse when you consider the RV-only solution from the Nespral et al. paper, which gives K=24.8±2.3 m/s and m_b = 71.7±6.3 Earth masses.

Damned….

http://www.nasa.gov/feature/mission-manager-update-kepler-spacecraft-in-emergency-mode

Mission Manager Update: Kepler spacecraft in emergency mode

Ouch... was looking forward to seeing what K2 could do as regards microlensing...

Kepler is now recovered and stable.

http://www.nasa.gov/feature/mission-manager-update-kepler-recovered-from-emergency-and-stable

System checks expected for the rest of this week, then hopefully it can begin the microlensing observations.