Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Astrophysics and Astronomy

PDF

Aerospace, Physics, and Space Science Faculty Publications

2007

Stars: Fundamental Parameters

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Spitzer Transit And Secondary Eclipse Photometry Of Gj 436b, Drake Deming, Joseph Patrick Harrington, Gregory P. Laughlin, Sara Seager, Sarah B. Navarro, William C. Bowman, Karen Horning Oct 2007

Spitzer Transit And Secondary Eclipse Photometry Of Gj 436b, Drake Deming, Joseph Patrick Harrington, Gregory P. Laughlin, Sara Seager, Sarah B. Navarro, William C. Bowman, Karen Horning

Aerospace, Physics, and Space Science Faculty Publications

We report the results of infrared (8 μm) transit and secondary eclipse photometry of the hot Neptune exoplanet, GJ 436b using Spitzer. The nearly photon-limited precision of these data allows us to measure an improved radius for the planet and to detect the secondary eclipse. The transit (centered at HJD p 2454280.78149 ± 0.00016) shows the flat-bottomed shape typical of infrared transits, and it precisely defines the planet-to-star radius ratio (±), independent of the stellar properties. However, we obtain the planetary radius, as well as the stellar mass and radius, by fitting to the transit curve simultaneously with an empirical …


Asteroseismology Of The Pg 1159 Star Pg 0122+200, Jianning Fu, Matt A. Wood Jan 2007

Asteroseismology Of The Pg 1159 Star Pg 0122+200, Jianning Fu, Matt A. Wood

Aerospace, Physics, and Space Science Faculty Publications

Context. The variable pre-white dwarf PG 1159 stars (GW Vir) are g-mode non-radial pulsators. Asteroseismology puts strong constraints on their global parameters and internal structure. PG 0122+200 defines the red edge of the instability strip and its evolutionary timescale is predicted to be dominated by neutrino emission. Its study offers the opportunity to better understand the instability mechanism and to validate the physics of the neutrino production in dense plasma. Aims. To achieve such a goal requires determining precisely its fundamental parameters. This is the goal of this paper. Methods. We present new multi-site photometric observations obtained in 2001 and …