CoRoT paper discussion
 
About 6 in attendance. Showed website design, send Susan suggestions for additional website links. We discussed a paper about a new planet discovered by CoRoT-Exo-3b. Transiting exoplanets from the CoRoT space mission VI. CoRoT-Exo-3b: The first secure inhabitant of the brown-dwarf desert http://adsabs.harvard.edu/abs/2008arXiv0810.0919D This is a survey that has set fields, observed for 150 days at a time. High precision photometry, wide field. Interesting aperture figure (3). Have RV measurements and good photometric follow-up. Discussion of figure 10.... dashed lines are density curves. They are discussing the region on the lower right of the plot... planet vs. brown dwarf classification. Formation mechanism has potential observables for the future... accretion gives enrichment in heavy elements. Maybe have a model to look metallicity -- of star and much more than star. Surveys are focused on slow rotators, could be a bias on objects found. Young and high mass --> fast rotator. Don’t want that for RV survey, results in observational bias. Massive stars and massive planets... figure 11 really intreaguing, but the statistical sample seems pretty small. Figure 12 -- short orbit periods <30 days. Different distribution from long period? Also consider metallicity. This object has a circular orbit which is different from other planets --> formation mechanism. 3 other objects in binary systems, they can’t rule that out for this object, but don’t really have the right type of data to determine binarity of star. Limb darkening and inclination are inter-related. Also R/R* calculation requires this. 2 vs. 4 parameter limb darkening model. Didn’t include equally probable solution in error bar for inclination. Fast or slow rotation changes the intensity map of the star over which a transit is occurring. Also if you consider the oblateness of the planet due to gravitational interactions with the star it changes the transit depth. These are measurable effects, but they are very difficult to determine/measure and interpret. How one interprets inclination and modeling of radius could change the entire model of the planet and where it lies on the mass-radius plot. They give one full solution (page 3) and mention another solution (page 4) without additional discussion. We are approaching the point where considering oblateness of the planet (changing the result by a few percent) may be important. Discussion of Remi’s talk on Monday. Some people were interested in the plot he showed considering Radio observations. Also have chapters from the Exo-Planet community group discussion, consider discussing individual chapters. Some discussion of observations of extra-solar planet and what you want -- spectral interpretation complicated, want as much info as you can get on an object, mass, period etc. The models are very complicated and there are a lot of values that one can tweak to get solutions that match the data. Next meeting -- October 23rd, 10:30am. Will discussion summary from DPS, Susan will send out a paper reference the week before. http://adsabs.harvard.edu/abs/2008arXiv0810.0919Dshapeimage_1_link_0
CoRoT paper discussion
Thursday, October 9, 2008