by Anthony Ayiomamitis
The light curve for exoplanet HAT-P-4b in Bootes depicted above is one of the later transiting exoplanets, having being discovered late 2007, and represents the fourth discovery by the Hungarian-based HATNet Project team. HAT-P-4b is characterized with a mass 68% times that of Jupiter and in spite of a larger radius (1.27 RJup), thus making this find a low-density hot Jupiter. HAT-P-4b requires 254 minutes to transit its parent star at a depth of 8 mmag (0.80)%. The parent star, BD+36°2593, is estimated to have a mass of 1.26 solar masses, a radius equivalent to 1.59 solar radii, a temperature of 5,860° K and to lie at a distance of 1011 light-years away with a visual magnitude of 11.21. Further details regarding HAT-P-4 and HAT-P-4b are available in the paper published by the discovery team led by G. Kovacs et al here.
Technical Details:
Date: Apr 22-23, 2010 @ 23:30:01 - 05:15:34 UT+3
Location: Athens, Greece (38.2997° N, 23.7430° E)
Equipment: AP 160 f/7.5 Starfire EDF, AP 1200GTO GEM, SBIG ST-10XME, SBIG CFW-10, SBIG Lum filter
Integrations: Lum: 158 x 120 sec, Dark: 15 x 120 sec, Flat: ~19,500 ADU, Binning: 2x2
Temperatures: Ambient: +14.0 ° C, CCD Chip: -20.0° C
The C- and K-stars used for the purposes of the differential photometry measurements depicted below were GSC 2569:1310 (mag 11.3) and GSC 2569:1092 (mag 11.5) respectively.
Further details here.