Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000aas...19712913s&link_type=abstract
American Astronomical Society, 197th AAS Meeting, #129.13; Bulletin of the American Astronomical Society, Vol. 33, p.714
Astronomy and Astrophysics
Astronomy
1
Scientific paper
The Grid Giant Star Survey (GGSS) is a partially-filled, all-sky survey for metal-poor K giants as potential constituents of the Astrometric Grid for the Space Interferometry Mission (SIM). The goal of the GGSS is to find the most distant K giants possible -- in order to minimize effects of binary companions, large planets, starspotting, and flaring on stability of astrometric photocenters -- while limiting the stars to V<13 (to minimize mission time expended on Grid observations). Virtually all potential jitter at the 1μ as level can be eliminated with pre-launch, ground-based study if Grid stars are at distances ≳ 1 kpc. Using the Swope 1-m telescope, we have nearly completed imaging 870 evenly-spaced, 0.4 deg2 fields with δ <+16o through the Washington M, T2 and (the stellar gravity-sensitive) DDO51 filters. Catalogues of photometrically-selected giant star candidates exist in >600 fields, along with estimated photometric parallaxes, d, for each star deduced from the coarse [Fe/H] resolution offered by our three-filter system. We initially select the four stars with M<13.5 projected to have the greatest d in each field as potential Astrometric Grid Stars, with the ultimate goal to winnow to one choice star per field for SIM. We find ~25% of fields to have at least one candidate with estimated d>5 kpc (and some with d>10 kpc). The typical photometric abundance of the latter stars is [Fe/H] ~-1.7. Over 50% of fields have at least one candidate with estimated d>3 kpc and almost all have at least one candidate with d>1 kpc. Because of variation in stellar density, the most distant candidates tend to be found at lower Galactic latitudes, until, below |b|=10o, dust obscuration reduces distances of viable candidates. All SIM Grid candidates will now undergo photometric variability (indicative of chromospheric activity) monitoring, as well as low and high resolution spectroscopic scrutiny to verify the gravity and metallicity of each star, and to search for radial velocity variability induced by companions.
Arenas Jose
Geisler Doug
Gieren Wolfgang
Johnston Kathryn V.
Kundu Anjan
No associations
LandOfFree
Properties of Stars Selected by the Grid Giant Star Survey for the Space Interferometry Mission Astrometric Grid does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Properties of Stars Selected by the Grid Giant Star Survey for the Space Interferometry Mission Astrometric Grid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Properties of Stars Selected by the Grid Giant Star Survey for the Space Interferometry Mission Astrometric Grid will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1729202