HW 4 Question3

VB10 was observed as part of the Stellar Planet Survey (STEPS) program whose goal is to discover and characterize the low mass companions of a sample of stars perviously believed to have no planets orbiting them. The Palomar observatory was used to detect evidence of this planet using the astrometry method. This method consists of precisely measuring a star's positions in the sky and observing its position changes over time.  Astrometric observation of VB 10 were taken over a nine year period starting in 1999 using 15 reference stars and 3 control stars. Though these observations, they were able to discover VB 10b, its having a planetary mass of 6 Jupiter-masses and an orbital period of 0.744 yrs. At the time, it was believed this system was a difficult target for RV observations and since transits probably do not occur. However, another team was also observing VB 10 as part of an on going search for planets around low mass star. They used high precision near-infrared radial velocity measurements. Observations were obtained during 12 nights and the team followed the methods described in the pervious paper. There did not detect reflex orbital motion caused by VB10b. The overall radial velocity measurement showed no significant variability. So They found no evidence for a giant planet orbiting VB10 similar to that detected via apparent astrometric perturbations by PS09.

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