TY - JOUR
T1 - Relative photometry of hat-P-1b occultations
AU - Béky, Bence
AU - Holman, Matthew J.
AU - Gilliland, Ronald L.
AU - Bakos, Gáspár Á
AU - Winn, Joshua N.
AU - Noyes, Robert W.
AU - Sasselov, Dimitar D.
PY - 2013/6
Y1 - 2013/6
N2 - We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph observations of two occultations of the transiting exoplanet HAT-P-1b. By measuring the planet to star flux ratio near opposition, we constrain the geometric albedo of the planet, which is strongly linked to its atmospheric temperature gradient. An advantage of HAT-P-1 as a target is its binary companion ADS 16402 A, which provides an excellent photometric reference, simplifying the usual steps in removing instrumental artifacts from HST time-series photometry. We find that without this reference star, we would need to detrend the lightcurve with the time of the exposures as well as the first three powers of HST orbital phase, and this would introduce a strong bias in the results for the albedo. However, with this reference star, we only need to detrend the data with the time of the exposures to achieve the same per-point scatter, therefore we can avoid most of the bias associated with detrending. Our final result is a 2σ upper limit of 0.64 for the geometric albedo of HAT-P-1b between 577 and 947 nm.
AB - We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph observations of two occultations of the transiting exoplanet HAT-P-1b. By measuring the planet to star flux ratio near opposition, we constrain the geometric albedo of the planet, which is strongly linked to its atmospheric temperature gradient. An advantage of HAT-P-1 as a target is its binary companion ADS 16402 A, which provides an excellent photometric reference, simplifying the usual steps in removing instrumental artifacts from HST time-series photometry. We find that without this reference star, we would need to detrend the lightcurve with the time of the exposures as well as the first three powers of HST orbital phase, and this would introduce a strong bias in the results for the albedo. However, with this reference star, we only need to detrend the data with the time of the exposures to achieve the same per-point scatter, therefore we can avoid most of the bias associated with detrending. Our final result is a 2σ upper limit of 0.64 for the geometric albedo of HAT-P-1b between 577 and 947 nm.
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U2 - 10.1088/0004-6256/145/6/166
DO - 10.1088/0004-6256/145/6/166
M3 - Article
AN - SCOPUS:84877934513
SN - 0004-6256
VL - 145
JO - Astronomical Journal
JF - Astronomical Journal
IS - 6
M1 - 166
ER -