High Precision Stellar Photometry by CCDs. II

High - precision photometry by telescope defocussing . II . The transiting planetary system WASP - 4 ⋆

We present and analyse light curves of four transits of the Southern hemisphere extrasolar planetary system WASP-4, obtained with a telescope defocussed so the radius of each point spread function was 17 (44 pixels). This approach minimises both random and systematic errors, allowing us to achieve scatters of between 0.60 and 0.88 mmag per observation over complete transit events. The light cur...

High Precision Photometry of Transiting Exoplanets

WFPC2 Stellar Photometry with HSTphot

HSTphot, a photometry package designed to handle the undersampled PSFs found in WFPC2 images, is introduced and described, as well as some of the considerations that have to be made in order to obtain accurate PSF-fitting stellar photometry with WFPC2 data. Tests of HSTphot’s internal reliability are made using multiple observations of the same field, and tests of external reliability are made ...

Techniques for Automated High-Precision Photometry of Sun-like Stars

Tennessee State University operates several Automatic Photoelectric Telescopes (APTs) located at Fairborn Observatory in the Patagonia Mountains of southern Arizona. The APTs are dedicated to photometric monitoring programs that would be difficult and expensive to accomplish without the advantages provided by automation. I describe the operation of two of the telescopes (0.75 and 0.80 m APTs) a...

High-precision Transit Photometry of OGLE-TR-10

We present B and I photometry of OGLE-TR-10 during transits of its giant planet. From our observations, we estimate the radius of the planet to be 1.16± 0.05 times the radius of Jupiter, assuming a stellar mass of M⋆ = 1.02 M⊙. This is smaller than previous estimates that were based on lower-precision data, and hence the planet is not as anomalous as was once believed. We provide updated determ...