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Tonight’s the Night

September 30th, 2007

Image Source.

Tonight, Sept. 30/Oct 1, is the night to follow-up to confirm whether HD 17156b can be observed in transit. Earlier this morning, I sent the following e-mail to the Transitsearch Observers list:

Hello Everyone,

I’d like to alert you to an important follow-up opportunity TONIGHT to observe HD 17156 for a possible transit by its companion planet. North American Observers are best situated for the event.

HD 17156 b has been the topic of several blog posts on oklo.org, see: [1], [2], [3], [4], [5].

Photometry taken by Jose Manuel Alemenara Villa on the Sept. 9/10 opportunity was suggestive of a possible transit with duration 169 minutes, a photometric depth of 0.007 magnitudes, and a mid-transit time of HJD ~ 2454353.614. These values are all quite close to what one would expect if HD 17156b is really transiting.

If the event observed by Alemenara Villa is due to a transit, then the next transit will be centered at HJD~2454374.83 (CE 2007 October 01 07:55 UT Monday) with the transit beginning at about 06:30 UT.

Observing should start as soon as possible this evening, and observers are encouraged to take photometry for as long as possible.

My fit to the published radial velocities predicts a transit midpoint centered at HJD 2454374.87 (CE 2007 Oct. 01 08:52 UT Monday), with a +/- 0.3d uncertainty in the time of central transit. The Alemenara Villa event sits nicely inside this window.

Thanks very much!
best regards,

It looks like much of the Southwest is clouded out, and although the skies outside here in Santa Cruz are currently cobalt blue, it’s predicted that clouds and even rain will materialize after midnight. SoCal, however, and many locations in the midwest and east look good to go. Here’s a selection of California predictions from the clear sky clock. This is a cool graphical tool for use in scheduling observations. Dark blue is good, white is bad.

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  1. andy
    October 4th, 2007 at 11:10 | #1

    Well it looks like some congratulations are in order on this one.

    Have transits of HD 80606b been ruled out yet?

  2. October 4th, 2007 at 12:57 | #2

    Hi Greg and co-authors,

    Just saw the preprint at the Exoplanet Encyclopedia
    site. Fantastic discovery. You beat COROT ;)


  3. NIKKI
    October 4th, 2007 at 14:15 | #3

    Congratulations, to Greg and to all co-authors:
    M. Barbieri, R. Alonso, G. Laughlin, J. M. Almenara, R. Bissinger, D. Davies, D. Gasparri, E. Guido, C.Lopresti, F. Manzini, G. Sostero!
    This is also success for systemic!

  4. greg
    October 4th, 2007 at 16:24 | #4

    Hey Guys,

    Thanks for your congratulations! The story behind the Sep 9/10 detection and Sept. 30/Oct. 1 confirmation is pretty interesting. I’m writing up a post on it right now. It should be up on the site shortly.


  5. October 4th, 2007 at 23:08 | #5

    Congratulations to all – very nice outcome of this pro-am network !

    Best regards,
    Tonny Vanmunster
    CBA Belgium Observatory

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