Astronomy and Astrophysics Seminars
A high-energy investigation of activity on potential planet hosts.
by Dr. Lalitha Sairam (University of Hamburg, Germany)
Tuesday, July 23, 2013
from
to
(Asia/Kolkata)
at Colaba Campus ( AG 66 )
at Colaba Campus ( AG 66 )
TIFR
Description |
Low mass stars make up nearly 75% of the stellar population making them the most common potential planetary hosts. They are in the focus of ongoing and planned surveys for habitable planet, since the distance of the habitable zone to the star decreases with decreasing stellar temperature and therefore the stellar mass. But due to extremely low luminosities of low mass stars the habitable zone moves closer to the star making the orbiting world extremely vulnerable to the effects of magnetic activity and the high energy emission from its host. Additionally, stellar activity is also an important obstacle in planet search surveys. To address this, I have characterised the low mass stars to disentangle radial velocity variation due to activity from the planetary companion. Magnetic activity in low mass stars is a widely observed phenomenon which manifests itself in features such as spots, flares and high-energy coronal emission. Active low mass stars are capable of producing flares of short as well as longer durations. As the most common potential planetary hosts, it is essential to understand the properties of flaring plasma, how frequently and powerful these flares, etc. Do the giant planet enhance the magnetic activity of their host star ? How do the planetary atmosphere behave in the high energy environment of an active host ? These are currently the key questions in extrasolar planetary science. In this talk, I will summarise the results and future prospects of my study on the coronal activity/high energy emission of nearby low mass stars, which can potentially host exoplanetary systems. |