ExSSII: mo’ better planets

We’re back, we’re tanned, we’re rested, we’re ready: 4th day, session 7,
in which Kepler annouces the discovery of the second circumbinary exoplanet…

Ok, we’re not going yet, but the press release came out at noon:

– 41d orbital period binary star, KV primary (bit less massive than the Sun).
Secondary is an M star.
Sub-solar metallicity, low eccentricity stellar orbit (e1=0.15)

about 60 pc away.

Planet is transiting, natch, 0.33 MJM
in a 229d near circular circumbinary orbit.

This is the second circumbinary planet discovered, after 1620-26b and the first orbiting two main sequence stars.

Press release


  1. #1 andy
    September 15, 2011

    This is the second circumbinary planet discovered, after 1620-26b

    So what about HW Virginis, DP Leonis, HU Aquarii, NN Serpentis, and UZ Fornacis?

  2. #2 Steinn Sigurdsson
    September 15, 2011

    Carter mentioned those as unconfirmed.
    Didn’t mention 1620-26.

  3. #3 andy
    September 15, 2011

    Interesting, was any particular reason given why these candidates should be regarded as less reliable than, say, RV planet detections?

    On the other hand B1620-26 is clearly irrelevant and not worth considering because it is a pulsar planet (same reason as why various RV planet people can keep claiming that they’ve found the “smallest known exoplanet” when their super-Earths exceed the mass of the innermost PSR B1257+12 planet by several orders of magnitude…)

  4. #4 Steinn Sigurdsson
    September 15, 2011

    Concern that the ETV might be due to stellar companions or other effects – he rattled a couple off, don’t know if they’re plausible alternatives quantitatively

    I think next IAU conference may have the “planets are only around main sequence stars” issue surface, in conjunction with the refighting of the great “what is a planet” battle.

    IAU already has a “an exoplanet is what we would call a planet in our solar system, but around another star” clause.

    I almost wanna see astronomers explain to the public why the Earth will no longer be a planet when the Sun becomes a white dwarf?
    And what about giants? Sub-giants?

    We’ll need lots of popcorn.
    And beer.

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