J/AJ/154/142 Corrected photometry for GJ 1132 for all eclipses (Dittmann+, 2017)
A search for additional bodies in the GJ 1132 planetary system from 21
ground-based transits and a 100-hr Spitzer campaign.
Dittmann J.A., Irwin J.M., Charbonneau D., Berta-Thompson Z.K., Newton E.R.
<Astron. J., 154, 142-142 (2017)>
=2017AJ....154..142D 2017AJ....154..142D (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, M-type ; Photometry, infrared
Keywords: eclipses - planets and satellites: individual: GJ 1132b -
stars: individual: GJ 1132 - stars: low-mass
Abstract:
We present the results of a search for additional bodies in the GJ 1132
system through two methods: photometric transits and transit timing
variations of GJ 1132b. We collected 21 transit observations of GJ 1132b
with the MEarth-South array. We obtained 100 near-continuous hours of
observations with the Spitzer Space Telescope, including two transits
of GJ 1132b and spanning 60% of the orbital phase of the maximum (6.9-day)
period at which bodies coplanar with GJ 1132b would transit. We exclude
transits of additional Mars-sized bodies, such as a second planet or a
moon, with a confidence of 99.7%. We find that the planet-to-star
radius ratio inferred from the MEarth and Spitzer light curves are
discrepant at the 3.7σ level, which we ascribe to the effects
of starspots and faculae. When we combine the mass estimate of the
star (obtained from its parallax and apparent Ks band magnitude)
with the stellar density inferred from our high-cadence Spitzer light
curve (assuming zero eccentricity), we measure the stellar radius of
GJ 1132 to be 0.2105-0.0085+0.0102 R☉, and we refine the
radius measurement of GJ 1132b to 1.130±0.056 R⊕. Combined
with HARPS RV measurements, we determine the density of GJ 1132b to be
6.2±2.0 g/cm3. We refine the ephemeris of the system (improving
the period determination by an order of magnitude) and find no evidence
for transit timing variations, which would be expected if there was a
second planet near an orbital resonance with GJ 1132b.
Description:
MEarth-South consists of eight f/9 40 cm Ritchey-Chretien telescopes
on German equatorial mounts situated at Cerro Tololo International
Observatory (CTIO) in Chile (Irwin et al. 2015csss...18..767I 2015csss...18..767I). The
telescopes are robotic and take data on every clear night. Each telescope
has a 2048x2048 pixel CCD, with a pixel scale of approximately 0.84"/pix.
We use a Schott RG715 glass filter with an anti-reflection coating, which
has a broadband red optical throughput.
Spitzer obtained data with the Infrared Array Camera at 4.5 µm as
program 12082 (PI Dittmann). We obtained 100 hr of nearly continuous
Spitzer observations, beginning on 2016 April 24 and ending on 2016
April 28 UT. Observations spanned from BJD 2457502.0064004 to
2457506.3296307.
Objects:
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RA (ICRS) DE Designation(s)
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10 14 51.89 -47 09 24.6 GJ 1132 = 2MASS J10145184-4709244
10 14 51.89 -47 09 24.6 GJ 1132b = GJ 1132 b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 209199 Photometry of GJ 1132
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See also:
J/AJ/153/191 : Transiting planet GJ 1132 (Southworth+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.6 d BJD [57332.2/57575.1] Barycentric Julian Date
(BJD-2400000)
14- 21 F8.6 --- NFlux [0.955081/1.02304]? Normalized flux
23- 30 F8.6 --- e_NFlux [0.001956/0.00825]? Error in NFlux
32- 38 A7 --- Inst Instrument used (Spitzer, MEarth)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 14-Jun-2018