HD 80606
AXA Light Curves

Links internal to this web page

    Basic data
    Table summary of transit measurements
    Transit LCs - Amateurs
    Transit LCs - Professionals
    OOT LC
    Finder image

Miscellaneous Information

Comments on LCs on this web page

This is a difficult target.

Basic Data

    RA = 09:22:37.6, DE = +50:36:13
    Season = February 07
    V = 8.5, B-V =

    HJDo = 4876.323 (35), Gillon (2009) global MCMC fit (reference below)
    P = 111.43637 (34) day, Gillon (2009) global MCMC fit
    Depth = 10.6 +- 0.8
mmag, Gillon (2009) global MCMC fit
    Length = 12.6 +- 1.7 hr, Gillon (2009) global MCMC fit

Table Summary of Transit Measurements

Transit Light Curves - Amateurs


Same data is plotted in next graph.

9924HVP  See previous graph for calification of UT coverage.

9924GBL  A "no show" for predicted ingress.

Transit Light Curves - Professionals

 This is my fit to Garcia-Melendo's data when a +3.5 mmag meridian flip zero-shift was applied to data after 24.9 UT.  Zero shifts matter and the reduced chi-square criterion allows for a wide range of zero-shift values. Consequently, uncertainties for mid-transit time, length and depth are greater than for any single zero-shift assumption (using chi-square). My subjective interpretation is that mid-transit HJD = 4876.30 +- 0.15, length = 11 +- 2 hrs, depth = 8.9 +- 0.5 mmag. The publication by Garcia-Melendo & McCullough give 4876.33 +-?, 11.3 +- ? and 10 +-? mmag.

This is my fit to Garcia-Melendo's data. Thanks, Enrique, for sharing your data with AXA. No zero shift was applied to meridian flip at 24.9 UT, as suggested by Garcia-Melendo.

Garcia-Melendo & McCullough LC, made with 24-inch telescope (reference below). See also my fit to Garcia-Melendo's data, above.

Fossey et al preprint LCs, made with 14-inch Celestron and 10-inch Meade telescopes (reference below).

Moutou et al LC, made with 48-inch telescope (reference below).

Out-of-Transit Light Curves

After egress (beginning of observations ~1.1 hrs after egress).

Before ingress (end of observations ~10 hrs before ingress).

Finder Image

HD 80606 and HD 80607 are a binary pair 20 "arc apart. FOV = 30 x 20 'arc, north up, east left.

Miscellaneous Information

Greg Laughlin produced this diagram of the HD 870606b orbit before the transit of 2009 February 13.


Greg Laughlin's depiction of the geometry for the primary transit of 2009.02.14 (created before the event).

Since Arizona observers failed to see an egress on the day before the Europeans observed egress it is possible to place an upper limit on transit length:  L <= 12 hours. This is illustrated by a graph that Greg Laughlin posted on his oklo web site. Here's a "lift" from that web page:

Greg Laughlin's constraint on L (from oklo web site: http://oklo.org/

This helps constrain the "impact parameter" (ratio = closest arc distance to star center ÷ star radius) to ~ 0.85.


    Gillon, M., 2009, "Spin-orbit missalignment for the transiting planet HD 80606b": http://fr.arxiv.org/abs/0906.4904
    Moutou et al  http://arxiv.org/abs/0902.4457
    Fossey et al http://exoplanet.eu/papers/fossey.pdf
    Garcia & McCullough, 2009 http://arXiv.org/abs/0902.4493
    Hebrard et al, 2010 http://fr.arxiv.org/abs/1004.0790

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WebMaster: Bruce L. GaryNothing on this web page is copyrighted. This site opened:  2009.02.28 Last Update:  2010.05.07