Cool Star Lab Undergraduates Present Research at Research Symposium


Undergraduate researchers in the Cool Star Lab presented their year’s work on May 28th, during the UCSD Faculty Mentor Program Undergraduate Research Symposium. This was the first Symposium to feature poster presentations by undergraduates.


Aishwarya Iyer presented her work on Spitzer Space Telescope monitoring observations of the TWA 30AB system. The goal of this project was to test the model laid out in Looper et al. (2010) that both systems are obscured to different degrees by circumstellar disks. TWA 30A, which highly variable (5 magnitudes) in the optical and less so in the near-infrared, is believed to be partially obscured by a slightly inclined disk; TWA 30B, which is heavily obscured (but not variable) in the optical and become more variable in the near-infrared, is likely an obscured source for which we see only reflected light emission in a varying disk morphology. This model was challenged in WISE observations in which TWA 30A appeared to be more variable at mid-infrared wavelengths, contrary to expectations. But 25 days of observation with Spitzer show that TWA 30B is clearly the more variable source, with a semi-periodic fluctuation with an amplitude of nearly a full magnitude, as well as color variations that may reflect different regions in its flared disk. Aisha is completing her analysis and preparing for the next set of data, 40 days with Spitzer including multiple observations over a 24-hour period.


Melisa Tallis presented her work looking for young brown dwarfs in the SpeX Prism Library, using the methodology of Allers & Liu (2013). Specifically, Melisa is comparing indices that are sensitive to temperature to those sensitive to pressure, and using the calibrations of this paper to assign gravity classifications. By examining a much larger sample (200 sources at this stage, 1000 source planned) than previously examined, she hopes to find previously unrecognized young brown dwarfs, whose kinematics she will compare to the BANYAN code to see if they reside in known young clusters.


Mike Lopez, who will be joining the Cool Star Lab in the summer, also presented his work with Prof. Kim Griest, using the Kepler database to look for microlensing signatures of primordial black holes.  He presented his theoretical calculations of what a microlens signature of such an object may look like, and demonstrated how such features would appear in stellar light curves. He will be mining the database over the summer.

Congratulations to these three students who have done a tremendous amount of work over the past year to achieve these results! Posters will be hung up in the hallway of the SERF building for those who would like to check them out.


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