Unprecedented accuracy in the fundamental parameters of stars from multiple stellar systems
Andrej Prsa
Villanova University
Eclipsing binary stars have long served as calibrators of the
fundamental stellar properties across the H-R diagram. Because of the
favorable geometric alignment and well understood dynamical laws that
govern the motions of the components, the modeling of their light and
radial velocity curves can provide us with masses, radii, temperatures
and luminosities to a precision better than 1-2%. NASA's Kepler mission
observed a 100-deg^2 patch of the sky in the Cygnus-Lyra region
essentially uninterruptedly for 4 years, and it attained an
unprecedented photometric precision of ~20ppm. The mission harvested
over 2600 eclipsing binaries; of those, ~20% were found to be triples
by means of eclipse timing variations. Most interestingly, there are
more that 30 objects that show tertiary transits, either by another
stellar companion or by a circumbinary planet. In those cases the
fundamental stellar parameters can be attained a full order of
magnitude more precisely than from eclipsing binaries alone, typically
to 0.1% and, in two cases, even better. I will present the methodology
and the first results of these studies, and stress the implications for
the low-mass end of the H-R diagram.
Date: | Jeudi, le 19 février 2015 |
Heure: | 11:30 |
Lieu: | Université de Montréal |
| Pavillon Roger-Gaudry, local D-460 |
Contact: | Tony Moffat |
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