Biomedical subjects

GW Henry

Publications and source records attributed to GW Henry.

2 recordsLinked to original sources

PubMed2000

Search for Transits of a Short-Period, Sub-Saturn Extrasolar Planet Orbiting HD 46375.

Precise brightness measurements of HD 46375 have been acquired with an automatic telescope to search for transits of its short-period, sub-Saturn extrasolar planet. Transits of the companion do not occur, indicating that the inclination of the orbit i is less than 83 degrees and sini is less than 0.992. This upper limit on sini still preserves the possibility that the mass of the planet is less than Saturn's. Analysis of the photometry for HD 46375 reveals no photometric variability larger than 0.0001+/-0.0002 mag at the orbital period of the planet. This effectively eliminates starspots and stellar pulsations as the cause of the radial velocity variations used to infer the planet's existence.

Journal Article↗

PubMed2000

A Transiting "51 Peg-like" Planet.

Doppler measurements from Keck exhibit a sinusoidal periodicity in the velocities of the G0 dwarf HD 209458, having a semiamplitude of 81 m s-1 and a period of 3.5239 days, which is indicative of a "51 Peg-like" planet with a minimum mass (Msini) of 0.62 MJup and a semimajor axis of 0.046 AU. Follow-up photometry reveals a drop of 0.017 mag at the predicted time (within the errors) of transit by the companion based on the velocities. This is the first extrasolar planet observed to transit its star. The radius of the planet derived from the magnitude of the dimming is 1.42 RJup, which is consistent with models of irradiated Jupiter-mass planets. The transit implies that sini>0.993, leading to a true mass of 0.62 MJup for the planet. The resulting mean density of 0.27 g cm-3 implies that the companion is a gas giant.

Journal Article↗