High-precision photometry by telescope defocussing. I. The transiting planetary system WASP-5
| Autor: | Martin Dominik, Christina C. Thöne, V. Bozza, Luigi Mancini, Jean Surdej, P. J. Wheatley, Gaetano Scarpetta, M. Zub, S. Calchi Novati, G. Masi, Colin Snodgrass, U. G. Joergensen, Timo Anguita, C. Liebig, S. Rahvar, Davide Ricci, Martin Burgdorf, Kasper Harpsøe, Per Kjaergaard, Allan Hornstrup, John Southworth, M. Mathiasen, Tobias C. Hinse |
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| Rok vydání: | 2009 |
| Předmět: |
Physics
Earth and Planetary Astrophysics (astro-ph.EP) Thermodynamic equilibrium FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Planetary system Light curve Atmospheric temperature Exoplanet law.invention Telescope Photometry (astronomy) Astrophysics - Solar and Stellar Astrophysics Settore FIS/05 - Astronomia e Astrofisica Space and Planetary Science Planet law methods: data analysis – methods: observational – techniques: photometric – binaries: eclipsing – stars: individual: WASP-5 – planetary systems High Energy Physics::Experiment Astrophysics::Earth and Planetary Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics - Earth and Planetary Astrophysics |
| DOI: | 10.48550/arxiv.0903.2139 |
| Popis: | We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54m telescope at ESO La Silla. In order to minimise both random and flat-fielding errors, we defocussed the telescope so its point spread function approximated an annulus of diameter 40 pixels (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to-point scatters of 0.50 mmag for the first transit and 0.59 mmag for the second. We construct detailed signal to noise calculations for defocussed photometry, and apply them to our observations. We model the light curves with the JKTEBOP code and combine the results with tabulated predictions from theoretical stellar evolutionary models to derive the physical properties of the WASP-5 system. We find that the planet has a mass of M_b = 1.637 +/- 0.075 +/- 0.033 Mjup, a radius of R_b = 1.171 +/- 0.056 +/- 0.012 Rjup, a large surface gravity of g_b = 29.6 +/- 2.8 m/s2 and a density of rho_b = 1.02 +/- 0.14 +/- 0.01 rhojup (statistical and systematic uncertainties). The planet's high equilibrium temperature of T_eq = 1732 +/- 80 K makes it a good candidate for detecting secondary eclipses. Comment: Accepted for publication in MNRAS. 9 pages, 4 figures, quite a few tables |
| Databáze: | OpenAIRE |
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