ExSSII: more transits

and we’re back, and I’m late, more Kepler stuff

hundreds of new multi-planet system (candidates) from Kepler!


  • v. good talk from Eric Ford – missed beginning
    Transit Timing Variations (TTV) in Kepler data

    confirmed, model constraints for 2 planet systems
    12 more candidates in the works, in preparation in several separate papers

    get independent mass estimates, expand parameter space, confirm planets
    for stars which are too faint or mass too low for RV confirmation
    Pull out lots of extra physics with TTV measurements, get to info not otherwise
    accessibility, some model dependence

    TTV sensitivity increases sharply with time,
    Eric reinforces the case for extended Kepler mission (hint, hint)

    Hey – Lee Billings is also here: “Hi Lee”

    Eric is a big tease…

  • and Jason is up.

    Hundreds(!!!) of new multi-planet candidate systems…

    Wow. I guess many planetary systems are very close to coplanar and densely packed…

    Let us not forget that Kepler measures the stars’ properties also.

    Can’t get over how clean and pretty the Kepler transit curves are.
    Astonishing relative photometric accuracy.

    218 with 2 planets
    73 with 3 planets
    ? with 4 planets
    ? wiith 5 planets
    2(?) with 6 planets

    went too fast for me… comment if you’re here and caught the 4 and 5 planet system numbers – there are fewer 4 than 3, and fewer 5 than 4, but more than 6

    some VERY small candidate planets in short orbital period – v. good relative photometry

    0..32 Earth radii at 4 days
    did someone say 0.9 Earth radii 20 something day orbital period
    0.5 Earth radii and 7 day period

    seeing the reflected light from planet and thermal emission from nightside through phase curve, for some systems

  • Ballard – KOI-88/Kepler-19b
    2.2 REarth transit with TTV
    just came out on arXiv Ballard et al 2011

    upper limit on RV less than 50 earth mass (assuming any e – 15 earh mass if e=0)
    arguing for why this is a real planet and not false positive – it is ok we believe you, we want to believe you!

    multiple transits – egress and ingress smeared in folded data ~ 5 min TTV with ~ 300d period – there is another planet – it is ok, we believe it is not a star!

    so Kepler-19c is potentially very interesting
    orbit/mass partially constrained – depends on whether it is in resonance
    low order mean motion resonance; or eccentric high order resonance;
    or retrograde moon; or co-orbital planet

  • Fabrycky: KOI-730 – 4 planet resonant chain planetary system
    7.4 9.8 14.8 and 19.7 d periods
    1.8 2.1 2.8 and 2.4 earth radii planets
    dense pack of super-earths

    4:3 — 3:2 — 4:3 or 3:4:6:8 resonance – cute

    see 15 sec TTVs for third planet, other TTVs too small with current data
    problem – with e=0 expect much larger TTVs
    floating TTVs drives to high eccentricity
    theoretically if you glide into first order resonances at low initial ecc then end in low ecc
    get ecc ~ 0.05 oscillating on decadal time scales
    get better fit to observed TTVs, more stable configuration

    looks plausible

  • JohnJohn – spectroscopy of Kepler giants
    KOI-254 case study
    looking at R > 5 REarth
    Keck HiRES followups to pick through the other Kepler planets

    Teff < 2,000 K V - 16.9 young M dwarf - M0 - half solar mass 2.5 d period, 0.036 transit depth distance unknown 100 m/sec RV amplitude e=0 M star measured properties not good fit to models, models kinda suck, too much chemistry hot transiting jupiter around a young M dwarf - that is different battery almost gone, can we make it to coffee before the laptop gives up... nice self-calibration technique for mass - can't figure the metallicity dependence, but I think JJ had it covered oh yes, there it is... next slide shows how you get [Z] also \KOI-254 - 0.6 Msun, 0.5 M_Jupiter - metal rich

  • Brian Jackson – Kepler and HAT-P-7b
    ellipsoidal variation
    subtle, small and worth measuring
    can and is measured
    but my battery is drained and so is tha laptops
    back after coffee

    why, yes, there area LOT of talks…


  1. #1 Lee Billings
    September 12, 2011

    Hi Steinn!

    Unfortunately, I’m not at EXSSII in the flesh. Though maybe it’s for the best: If I were there, you can bet I’d have consumed unreasonable amounts of caffeine to help me drink from the firehose of results, and I’d have probably bounced into you and spilled coffee everywhere by now.

    So instead I’m sitting here comfortably on my back porch, sipping water instead of coffee, enjoying the nice weather and your excellent updates. Really appreciate your live-blogging — keep it up if you can! I know at least 2 or 3 other journo-types who seem to be quite reliant on your posts from this conference. But hopefully you’ll get a chance to go outside, too, and spend some time beneath the stars with the buffalo beside the hydrothermal springs.



  2. #2 Dunkleosteus
    September 14, 2011

    The number of multi-planet system (courtesy of GovertTweets):

    158 new mutli-transit candidate systems. current count: 218×2, 75×3, 25×4, 8×5, 2×6 says jason rowe #ESS2

New comments have been temporarily disabled. Please check back soon.