"Retired" Planet Hosts: Not So Massive, Maybe Just Portly After Lunch
| What | |
|---|---|
| When |
2012-01-20 14:00
2012-01-20 15:00
2012-01-20 from 14:00 to 15:00 |
| Where | Cody Hall |
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James P. Lloyd (Cornell University)
Studies of the planet abundance as a function of stellar mass have
suggested a strong increase in the frequency of planet occurrence around
stars more massive than 1.5 Msun, and that such stars are deficit in
short period planets. These planet searches have relied on giant stars
for a sample of high mass stars, which are hostile to precision Doppler
measurements due to rotation and activity while on the main sequence.
The observationally inferred mass for exoplanet hosting giants show
discrepancies that can be explained by erroneous mass determinations of
some exoplanet host stars. By comparison with a mass distribution
function constructed from integrating isochrones, the exoplanet hosts
are inconsistent with a population of massive stars. These stars are
more likely to have originated from a main sequence population of late
F/early G dwarfs with mass 1.0-1.2 Msun, only slightly more more massive
than the typical FGK dwarfs with Doppler detected planets. The deficit
of short period planets is most likely explained by tidal capture. The
planet abundance difference requires either a steeper increase in planet
frequency with mass than previously thought or a high rate of false
positives due to signals of stellar origin.


