ExSSII: planets around binaries or in clusters

Planets in binaries and star clusters: session 7 of Extreme Solar Systems II

planets around binaries? in clusters? crazy stuff...

and we are live...

  • Carter - from Kepler on transiting circumbinary planets
    Obviuous Star Wars quip
    Some eclipse timing variations in 3 eclipsing stellar binaries, hint at possible circumbinary planets.

    Kepler-16b - transiting circumbinary planet
    Doyle et al Science 16th Sept 2011

    Planet as reported above, sub-Jovian, coplanar orbit with K+M star binary (l[Z] = -0.3)
    41d stellar orbital period, 229d planet orbital period,
    stellar binary e=0.15, planet orbit e=0.0069

    Very high precision radius measurements, mass from eclipse time variation,
    large transit timing variations due to primary moving around barycenter
    - get mass to about 5%
    MKepler16b = 0.33 MJ
    density ~ 1

    cool animations, look for them on the web press release, can't upload figs or anims from up here

    Ok, I'm a big meanie, I asked if they were really claiming first circumbinary, but I let someone else ask an upbeat question first...

    How come planet orbit is so very circular? That is a puzzle?
    Lucky phase of oscillating outer eccentricity? Or just far enough out to not be perturbed???

    Editorial Comment: Most stars in binaries - very important to know if planets for easily in binaries to know real occurrence rate of binaries. RV searches tend to avoid binaries when they can, and transiting searches have problems with binaries as contaminants.

  • Welsh - from Kepler on non-transiting circumbinary planets
    more binary planets?!
    Looking at eclipsing timing variations to sub-min--hour long precision in Kepler eclipsing binaries as signature of planetary candidate companions
    Orosz et al in prep.
    Many interesting candidates.
    Going too fast... one slide per minute, max!
    1063 eclipsing binaries, 750 with secondary eclipses,
    with 150 tertiary candidates from timing!!!
    Dozen or more circumbinary exoplanet candidates.
    One spectacular candidate shown.

    Also looks like another transiting exoplanet around KOI-2459!
    A third candidate transiting circumbinary exoplanet around unnamed system...

    Looking very promising for exoplanet binaries - which is very important.
    Very very very important.

  • Narita - looking for secondary stellar companions to know transiting planets
    Direct imaging of known systems with transiting exoplanets.
    10 candidates observed.

    Using Subaru telescope, adaptive optics with high contrast imaging,
    SEEDS - 120 nights over 5 years, primarily looking for direct imaging of substellar objects

    Systems observed include HAT-P-7 and HAT-P-11 and 8 others not named.
    Many candidate companions (duh) - second epoch to look for common proper motion.

    HAT-P-7 has faint common proper motion companion
    known long term RV trend in system,
    Kozai effect inhibited by companion, system formed from internal scattering (?)

    HAT-P-11 had several candidate companions
    no common proper motions

    good point in questions about doing some statistics on faint background objects,
    depends on field of course, we actually have some numbers on that somewhere from imaging searches of WD companions

  • Chauvin - HD196885 - NO SHOW
  • Zoe Leinhardt - Collision Planet Formation

    Looks at known planets in binaries, how does it inform models of planet formation
    Fast summary of diverse planet formation scenarios.

    Are planetesimals sticky or do they shatter, that is the question.

    Leinhardt & Stewart submitted 2011
    particle simulations of planetesimal collisions over range of sizes and velocities and impact parameter (composition?) and mass ratios of impactors


    mapping shattering vs sticking and mass spectrum(?) of fragments

    conclusion - need relative impact speed ~ explains solar system objects nicely

    but... what happens to fragments next in shattering events?

    binary systems tend to drive relative impact speeds up

    Two-in-one special: also a model for Γ Ceph exoplanet in binary stellar system

    growth for low i ,e at a2/a1


  • Chatterjee - Planets in Dense Clusters

    dynamics of planetary systems in dense stellar clusters

    NB 4 NGC open clusters in Kepler field. espec. NGC 6791 metal rich, massive and dense
    monte carlo code sim
    - planets survive in NGC6791 environments, consistent with previous conclusions by Davies, Bonnell and yours truly.

    only 1 planet per star?
    perturbations would be more significant if there were multiplanet systems

    expect Kepler to see handful of giant planets in NGC 6791 modulo assumptions, going down to 18th magnitude, if possible

ok, I'm biased...

Planets in Clusters

Circumbinary Planets


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Hi Steinn,

Thanks for the live blogging. It is the next best thing for those of us who
could not make the conference.

The animations that went along with the Kepler 16 press release
are really quite nice. Likewise, the press conference, which I watched
over NASA TV, was also well done. Hopefully they will have that
video on some NASA page somewhere.


By Jerome Orosz (not verified) on 15 Sep 2011 #permalink

Hi Steinn,
it is always really impressive how quick you are in live blogging. I will leave some comments clarifying some points from the "Planets in Star Clusters" talk.
There were 1 planet around 1 star. Question is what if there were multiples? There are two parts in the answer.
A distant planet in a multiple planet system may have crossing orbits with the inner system at ~ few % level. So for detectable fraction things should not change much.

On the other hand if someone is in love with crazy stuff, this few % is quite a few by number in this cluster. For example, 10% is ~ 400 planet hosting stars. These interacted systems may form exotic orbits.

One such interaction could create the high-e high-inclination planet you need in your explanation of LHB. :)

By Sourav Chatterjee (not verified) on 16 Sep 2011 #permalink