NOAO > Observing Info > Approved Programs > 2009B-0432
|
NOAO > Observing Info > Approved Programs > 2009B-0432 |
|
PI: Sergio Dieterich, Georgia State University, dieterich@chara.gsu.edu
Address: Department of Physics and Astronomy, Atlanta, GA, 30303, USA
CoI: Todd Henry, Georgia State University
Title: Probing Stellar Physics at the Bottom of the Main Sequence: Connecting Masses to Photospheric Observables
Abstract:
We propose to obtain resolved JHK photometry of 27 Very Low Mass (VLM)
binaries using NIRI+ALTAIR on Gemini North. 15 targets have large astrometric
perturbations indicative of a companion. 9 targets were resolved with HST/FGS
as binaries, but do not have resolved infrared photometry. Obtaining resolved
JHK photometry is crucial for a physical characterization of these objects,
as VLM stars have their peak flux in the near infrared. JHK photometry is
often used as the starting point for determining bolometric luminosities for
VLM stars. Due to the large amount of near infrared data available from the
2MASS survey, the near infrared color space is currently the most widely
populated color space when studying low mass stars and brown dwarfs. 2
targets were marginally resolved in an HST/NICMOS search for close companions
to nearby stars and again lack photometry. One last target with known
trigonometric parallax is over-luminous in a manner consistent with it being
an unresolved binary with nearly equal fluxes from both components. Much work
has been done in the field of Very Low Mass stars during the past decade, but
the fundamental question of where the exact boundary between stellar and
sub-stellar objects lies is still largely unanswered. This is due to the lack
of reliable observational tests that discriminate between the most massive
brown dwarfs and the least massive stars. Characterizing objects near this
boundary is a fundamental aspect of the PI's doctoral thesis. We will use the
resolved infrared photometry to place these Very Low Mass objects in
color-magnitude diagrams and start mapping orbits, thus further populating
the Mass-Luminosity Relation in this critical and as of yet sparsely
populated mass range.
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-0432 |
|