by Medeiros, Setiawan, Hatzes, Pasquini, Girardi, Udry, Dollinger, and da Silva
Astronomy and Astrophysics 2009
Medieros et. all discovered a 835.477±6.04 day period, Msin i = 11.1(9.5) MJup planet around HD110014. Relevant to my research, HD110014 is an evolved higher mass star, but is not in a cluster. The bracketed value after the quoted mass is a result from not knowing the mass of the sun. After computing the PDF for the mass of the main star by summing over all possible parts of all possible isochrones it could belong to, there is roughly equal probabilities of it being a 1.55 Gyr 1.9Msun star, or a 0.68Gyr 2.5 Msun star. A slightly higher C12/C13 ratio gives weight to the 2.5 Msun solution, but both still exist. The 9.5Mjup solution for the mass arises under treating the star as a 1.9Msun star instead of a 2.5Msun star.
After removing the planet, a 130 day periodicity remains. This may be a result of a planet, but the evidence is not strong enough to convincingly say so. Treating and it as a planet and removing from the residuals eliminates all remaining periodicity in the signal.
In order to determine that the 835 period is not the result of stellar phenomena, they ran several tests. I need to read other papers specifically on the bisector velocity span and CaII H&K emission lines in order to understand them better. They also studied the visual magnitude that came from the Hipparcos data. It was classified as a non-periodic star, and no significant peak appeared in the periodogram at 835 days.
Nice post. This is exactly what I want to see on a ~daily basis.
ReplyDeleteYou can read more about CaII H&K in Wright et al. (2004). Check out Stellar Atmospheres by David Gray in the library to learn more about bisector spans.