J/ApJ/731/123 APOSTLE light curve of GJ 1214b (Kundurthy+, 2011)
APOSTLE observations of GJ 1214b: system parameters and evidence for stellar
activity.
Kundurthy P., Agol E., Becker A.C., Barnes R., Williams B., Mukadam A.
<Astrophys. J., 731, 123 (2011)>
=2011ApJ...731..123K 2011ApJ...731..123K
ADC_Keywords: Planets ; Photometry ; Stars, double and multiple
Keywords: methods: statistical - planetary systems - stars: activity -
stars: fundamental parameters
Abstract:
We present three transits of GJ 1214b, observed as part of the Apache
Point Observatory Survey of Transit Light Curves of Exoplanets
(APOSTLE). By applying Markov Chain Monte Carlo techniques to a
multi-wavelength data set which included our r-band light curves and
previously gathered data of GJ 1214b, we confirm earlier estimates of
system parameters. Using spectral energy distribution fitting,
mass-luminosity relations, and light curve data, we derived absolute
parameters for the star and planet, improving uncertainties by a
factor of two for the stellar mass
(M*=0.153+0.010-0.009M☉), stellar radius
(R*=0.210+0.005-0.004R☉_), planetary radius
(Rp=2.74+0.06-0.05R{earth}), and planetary density
(ρp=1.68±0.23g/cm3). Transit times derived from our study
show no evidence for strong transit timing variations. We also report
the detection of two features in our light curves which we believe are
evidence for a low-energy stellar flare and a spot-crossing event.
Description:
We observed three transits of GJ 1214b on UT dates 2010 April 21, 2010
June 6, and 2010 July 6 using the ARC 3.5m Telescope at Apache Point,
New Mexico. All observations were made with Agile, a high-speed
time-series CCD photometer. All APOSTLE light curves presented in this
work were collected using the r-filter (similar to the Sloan Digital
Sky Survey r filter).
Objects:
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RA (2000) DE Designation(s)
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17 15 18.94 +04 57 49.7 GJ 1214 b = GJ 1214 b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 87 837 APOSTLE lightcurve
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date Date of the observation; UTD (2010/04/21,
2010/06/06 and 2010/07/06)
12- 26 A15 --- Desc Light curve description (Flare Data Only,
No Flare, No Spot or Spot Data Only)
28- 42 F15.12 d BJD [-0.105/0.091] Barycentric Julian Date minus
mid transit time
44- 57 F14.12 --- NFlux [0.97/1.01] Normalized flux ratio
59- 72 F14.12 --- e_NFlux Error in NFlux
74- 87 F14.12 --- MFlux [0.98/1] Model light curve (1)
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Note (1): We use the light curve models described in Mandel & Agol
(2002ApJ...580L.171M 2002ApJ...580L.171M) assuming quadratic stellar limb darkening and
a circular planetary orbit. Our transit code can fit for multiple
transits simultaneously and allow for multiple sets of limb-darkening
coefficients when data gathered using different filters are used.
See section 3.1 for further explanations.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 25-Oct-2012