Gr@v Seminar - Stellar parameters of M dwarfs: exploring the star-planet relation - 20 novembro 2013
Stellar parameters of M dwarfs: exploring the star-planet relation
Abstract / Resumo
M dwarfs are the faintest, coldest and smallest stars in the main sequence. Ubiquitous and long lived, M dwarfs comprise about 70% of all stars in the Galaxy and around half of its baryonic matter. However, despite being so omnipresent and close-by, not a single M dwarf can be seen with the naked eye, due to their very low intrinsic brightness.
They are also one of the least understood stellar types. M dwarfs are hard to study, not just due to their faintness but mostly to their highly complex spectra, where, in the visible, the continuum disappears in a forest of billions of weak molecular lines. For some time M dwarfs were relatively ignored but in the last few years the radial velocity and transit planet search programs sparked a growing interest in these stars. Indeed, as M dwarfs are smaller in mass and radii, the reflex motions induced by planets and their transit depths are considerably larger, when compared to the same effects induced to the more massive, and better studied, FGK stars. Moreover, the habitable zone in M dwarfs is situated in tighter orbits, which makes the detection of potentially habitable planets easier with radial velocity and transit techniques, as both have their best sensitivity closer to the host star.
In this talk I will present a new high-precision metallicity and effective temperature calibration for M dwarfs, where a precision of 0.08 dex and 100K for [Fe/H] and Teff was achieved. Then, I will report the results of my recent study on the star-planet relation of the HARPSM radial velocity planet search survey. Finally I will demonstrate the impact of precise stellar parameters on the determination of the planetary mass and radii of transiting planets around M dwarfs.
20 de novembro de 2013 | 15:00
Physics Department Aveiro University
Campus de Santiago
3810-183 Aveiro, Portugal