NOAO > Observing Info > Approved Programs > 2009B-0142
|
NOAO > Observing Info > Approved Programs > 2009B-0142 |
|
PI: Andreas Seifahrt, University of Goettingen, seifahrt@astro.physik.uni-goettingen.de
Address: Institute for Astrophysics, Friedrich-Hund-Platz 1, Goettingen 37073, Germany
CoI: Jacob Bean, University of Goettingen
CoI: Todd Henry, Georgia State University
Title: Rotation periods and activity of low mass stars: supporting a large near- infrared radial velocity campaign
Abstract:
We have been granted a large programme (33 nights over four
semesters) with CRIRES to conduct a radial velocity search programme on
about 40 mid- to late M dwarfs. We developed an absorption cell for
CRIRES which allows us to achieve detection limits of about 5 m/s,
precise enough to find Neptune mass planets around most of these stars.
We propose here for supporting photometric observations addressing two
important points: (1) We need to measure the rotational periods of all
targets of our RV programme to (a) estimate the inclination angle of the
stars (which is likely the same for the orbital inclination of their
planets) and (b) to distinguish between a RV signal induced by a planet
and a 'false' RV signal due to star spots. (2) It is commonly believed
that due to the reduced contrast between stellar spots and photosphere
in the nIR, photometric and RV signatures from stellar activity are
notably reduced at longer wavelength. However, empirical results
supporting this assumption are still preliminary. We thus propose to
monitor the activity level of our targets with simultaneous photometry
in the optical and in the near infrared in parallel to our VLT/CRIRES
observations. Variability in the photometric signal is a direct result
of the activity of the stars and the ratio in amplitude between the
optical and near infrared allows us to determine the spot temperatures
and surface area, as well as the lifetimes of these features.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
|
NOAO > Observing Info > Approved Programs > 2009B-0142 |
|