Physical Sciences and Mathematics Commons^™

The Hubble Pancet Program: An Extensive Search For Metallic Ions In The Exosphere Of Gj 436 B, Leonardo A. Dos Santos, David Ehrenreich, Vincent Bourrier, Alain Lecavelier Des Etangs, Mercedes López-Morales, David K. Sing, Gilda E. Ballester, Lofti Ben-Jaffel, Lars A. Buchhave, Antonio García Muñoz, Gregory W. Henry, Tiffany Kataria, Baptiste Lavie, Panayotis Lavvas, Nikole K. Lewis, Thomas Mikal-Evans, Jorge Sanz-Forcada, Hannah R. Wakeford

Information Systems and Engineering Management Research Publications

Context. The quiet M2.5 star GJ 436 hosts a warm Neptune that displays an extended atmosphere that dwarfs its own host star. Predictions of atmospheric escape in such planets state that H atoms escape from the upper atmosphere in a collisional regime and that the flow can drag heavier atoms to the upper atmosphere. It is unclear, however, what astrophysical mechanisms drive the process.

Aims. Our objective is to leverage the extensive coverage of observations of the far-ultraviolet (FUV) spectrum of GJ 436 obtained with the Cosmic Origins Spectrograph (COS) to search for signals of metallic ions in the upper …

Long-Term Spot Monitoring Of The Young Solar Analogue V889 Herculis, Teemu Willamo, Thomas Hackman, Jyri J. Lehtinen, Maarit J. Käpylä, Ilya Ilyin, Gregory W. Henry, Lauri Jetsu, Oleg Kochukhov, Nikolai Piskunov

Information Systems and Engineering Management Research Publications

Context. Starspots are important manifestations of stellar magnetic activity. By studying their behaviour in young solar analogues, we can unravel the properties of their magnetic cycles. This gives crucial information of the underlying dynamo process. Comparisons with the solar cycle enable us to infer knowledge about how the solar dynamo has evolved during the Sun’s lifetime.

Aims. Here we study the correlation between photometric brightness variations, spottedness, and mean temperature in V889 Her, a young solar analogue. Our data covers 18 years of spectroscopic and 25 years of photometric observations.

Methods. We use Doppler imaging to derive …