Meeting of Astrophysics Students at Stanford (MASS) Double Header: JB Ruffio and Joey Murphy

Date: 
1:15pm to 2:15pm
Tuesday August 1st, 2017

Stars and Planets!

Joey:

The study of the spectra of young, actively accreting stars (e.g. T Tauri stars) can constrain their stellar properties and offer insight on how pre-main sequence stars evolve. Spectroscopic observations simultaneously measure the sum of the star's intrinsic photospheric flux and any emission resulting from hot gas shocking as it accretes onto the star from its protoplanetary disk. These accretion signatures "veil," or fill in, the stellar photosphere and complicate measurements of stellar properties like effective temperature and composition. In practice, the veiling has traditionally been assumed to be a simple, constant continuum excess. With the combination of high resolution optical spectra of the T Tauri star LkCa 15, and our use of a statistically rigorous analytical framework (Gaussian Processes), we challenge the assumption of a constant continuum veiling excess. In better understanding the spectral structure of the accretion, we hope to more accurately infer the star's stellar properties and provide a better understanding of accretion in young stars.

JB:

During its 3.5 years lifetime, NASA Kepler spacecraft has discovered over 4000 transiting exoplanets candidates including over 2300 confirmed planets.  Kepler has shown that the most common planets, which have no analog in the Solar system, are bigger than Earth and smaller that Neptune, so called Super-Earths or mini-Neptune. We are trying to understand if these planets are rocky planets with a puffy atmosphere or if they compare better with gas giants.

Kepler was sensitive to planets relatively close to their star with orbital periods less than a year. At much longer orbital periods, direct imaging is probing the edge of stellar systems. By combining all the detection methods, we will able to explain how planets form and what they are made of.

Location: 
Campus, PAB 214