Relative photometry of hat-P-1b occultations

Bence Béky, Matthew J. Holman, Ronald L. Gilliland, Gáspár Á Bakos, Joshua N. Winn, Robert W. Noyes, Dimitar D. Sasselov

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Article number166
JournalAstronomical Journal
Volume145
Issue number6
DOIs
StatePublished - Jun 1 2013

Fingerprint

occultation
albedo
Hubble Space Telescope
reference stars
photometry
planets
atmospheric temperature
planet
extrasolar planets
spectrographs
artifacts
temperature gradients
telescopes
temperature gradient
artifact
stars
orbitals
air temperature
time series
exposure

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Béky, B., Holman, M. J., Gilliland, R. L., Bakos, G. Á., Winn, J. N., Noyes, R. W., & Sasselov, D. D. (2013). Relative photometry of hat-P-1b occultations. Astronomical Journal, 145(6), [166]. https://doi.org/10.1088/0004-6256/145/6/166
Béky, Bence ; Holman, Matthew J. ; Gilliland, Ronald L. ; Bakos, Gáspár Á ; Winn, Joshua N. ; Noyes, Robert W. ; Sasselov, Dimitar D. / Relative photometry of hat-P-1b occultations. In: Astronomical Journal. 2013 ; Vol. 145, No. 6.
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Béky, B, Holman, MJ, Gilliland, RL, Bakos, GÁ, Winn, JN, Noyes, RW & Sasselov, DD 2013, 'Relative photometry of hat-P-1b occultations', Astronomical Journal, vol. 145, no. 6, 166. https://doi.org/10.1088/0004-6256/145/6/166

Relative photometry of hat-P-1b occultations. / Béky, Bence; Holman, Matthew J.; Gilliland, Ronald L.; Bakos, Gáspár Á; Winn, Joshua N.; Noyes, Robert W.; Sasselov, Dimitar D.

In: Astronomical Journal, Vol. 145, No. 6, 166, 01.06.2013.

Research output: Contribution to journalArticle

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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 - 2013/6/1

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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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Béky B, Holman MJ, Gilliland RL, Bakos GÁ, Winn JN, Noyes RW et al. Relative photometry of hat-P-1b occultations. Astronomical Journal. 2013 Jun 1;145(6). 166. https://doi.org/10.1088/0004-6256/145/6/166