PHY390GMU

     In the article by Pravdo and Shaklan, a companion of the star VB 10 is stated to be found through the astrometric method using the Stellar Planet Survey (STEPS) program. They noted that in previous observations of the star it had seemed to contain no planets, however the precisions were too large (1.1-1.5 km/s) in range to be able to file this as fact. The STEPS program observes in R band wavelengths and calculates "reflex motion of a target star around the system center of mass" and then it "is compared to a grid of reference stars in the same field." The reference list for this experiment involved 15 stars and astrometric observations were taken over 9 years. They tested astrometric sensitivity by using two different sets of reference stars in each observation. This negates results being due to the reference stars themselves.      After obtaining the data, they created a periodogram to analyze VB 10 and the control stars using the Lomb-...

The planet orbiting VB 10 was originally “discovered” using the Stellar Planet Survey (STEPS) program via the astrometric method. Their data were taken over a period of 9 years and made use of 15 reference stars. Two different sets of reference stars were used as a check to ensure that their results are not just a product of their chosen reference stars. The authors constructed a periodogram of VB 10, as well as the reference stars, and analyzed them using the Lomb-Scargle algorithm. They computed a False Alarm Probability (FAP) for a variety of periods and found that the smallest FAP occurred for a 0.74 year period (with a 3E-3 % chance of being false). None of the reference stars show a significant FAP at 0.74 years. They also fit their data (as well as existing RV data) to a Keplarian model. This model showed that the 0.74 year period is indeed the best fit. This fit also helped to infer possible planet masses, of which the most likely of about 6.4 Jupiter masses. This was refuted l...

Summary of two articles concerning VB 10. VB 10 is ultra-cool dwarf star that was reportedly, by Pravdo and Shaklan, to have the first extrasolar giant planet orbiting with a mass of 6.4 (+2.6,−3.1) Jupiter-masses (MJ) and an orbital period of 0.744 (+0.013,−0.008) yrs. This discovery was obtained with the Stellar Planet Survey (STEPS) program over a span of 9 years. They researchers used the astrometry method using a variety of reference  stars. They attempted to provide explanations for arguments that might arise after their discovery, specifically, radial velocity measurements. They declared the radial velocity observations obsolete  due to their insufficient   precision  measurement of 1.1-1.5 km s -1   . However, they were unsuccessful in proving the existence  of the star due to an article published by Bean et al. which refuted their discovery through radial velocity analysis of the star on the Very Large Telescope with the precision of the measu...

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 veloci...

The planet orbiting VB 10 was a very interesting case given the circumstances of what it is and the star that it orbits. VB 10 is an ultracool M-Dwarf star close to the lower mass limit of what we consider a star to be The planet orbiting VB10 is roughly 6.4 Jupiter masses with an orbital period of 0.744 years (271.56 days) and was detected using the radial velocity method.But detecting a solar system in this way is very strange indeed since the radial velocity method is predominately used on what we can see visably, but the star is an ultracool M-Dwarf which typically makes stars like this too dim to see properly. To measure radial velocity from the near Infrared spectrum is the most optimal means of detecting these systems, but using the CRIRES on an ammonia gas cell, the odds were found to be a bit too out of the ordinary. Currently this technique is incredibly outshined (excuse the pun) by systems detected in visible light, but the problem there lies within the incredibly large fal...