GJ 1214
AXA Light Curves

Links internal to this web page:
    Basic data
    Table & plots of of AXA transit measurements
    Amateur Transit LC's
    Professional Transit LC's
    OOT LCs
    Finder images


Super-Earth (radius = 2.7 x R_Earth, mass = 6.5 x M_Earth), discovered by MEarth observing system at Mount Hopkins. I include it in the BTE in spite of its faint V-mag partly bercause it's such an important exoplanet and also because with a long wavelength filter (NIR is best choice, but R-band or z-band will do) it's not so faint because the star is so red.

Basic data

    RA = 17:15:18.9, DE = +04:57:50
    Season = June 13
V = 14.67, J=9.750, K=8.782 (B-V > 1.5, very red)
    HJDo = 4999.712703 (126) and P = 1.5803925 (117) days (as listed in Schneider's Extrasolar Planets Encyclopaedia, HJDo corrected from earlier value)
    Depth = 17.5 ± 1.5 mmag (NIR-band)
    Length = 0.85
± 0.10 hr (NIR-band)
    Fp = 0.??
± 0.??, F2 = 0.?? ± 0.??
    b = 0.354

Table & Plots of Amateur Observations 

Amateur Light Curves

Gregor Srdoc (Croatia) observed GJ 1214 on 20 nights and produced this phase-folded LC. The data include 3 transit events but are mostly OOT. 
This phase-folded LC can be used to rule out the presence of a second transiting exoplanet at the 10 mmag level (Gregor writes), keeping in mind that a second planet transit won't have the same period and therefore won't appear "in phase" with the primary exoplanet "b".  Gregor used a 12-inch telescope and SBIG ST-7XME CCD. Each night the star filed was placed a the same pixel location and an autoguider kept the star field fixed to the pixel field throughout the observing session. His filter was a longpass R (Baader Planetarium). Defocusing allowed for exposure times of 240 seconds. The photometric readings of target and reference stars were de-trended and phase folded using Peranso (by Vanmunster).


Professional Light Curves

Copied from discovery paper by Charbonneau et al (2009)

Out-of-Transit (OOT) Light Curves

See caption for this figure in Amateur Light Curves section, above.

Finder Charts

Beware the (apparent) Delta Scuti variable (GSC 408:113) located 1.3 'arc south of GJ 1214 when choosing reference stars.  Colin Littlefield has measured the "variable" on several occasions to have a period of ~ 6 hrs with an amplitude of ~ 0.1 magnitude. (Image from SkyMap)

Phase-folded  LC for GSC 408:113, produced by Gregor Srdoc (Croatia). Since the two minima are not exactly the same the period has two minima and two maxima. Gregor calculates the period to be 0.4562 days (10.95 hours). This data is from the same set of images used to create the GJ 1214 full-phase folded LC, described above.


Discovery paper: Charbonneau et al, 2009, http://fr.arxiv.org/abs/0912.3229

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WebMaster: Bruce L. GaryNothing on this web page is copyrighted. This site opened:  2009.12.20 Last Update:  2010.07.16