NOAO > Observing Info > Approved Programs > 2007A-0454
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NOAO > Observing Info > Approved Programs > 2007A-0454 |
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PI: Hugh C. Harris, US Naval Observatory, hch@nofs.navy.mil
Address: 10391 W. Naval Observatory Rd., Flagstaff, AZ 86001, USA
CoI: Arne Henden, AAVSO
CoI: Conard Dahn, US Naval Observatory
CoI: Jeffrey Pier, US Naval Observatory
Title: Spectra to Support Accurate Parallaxes
Abstract:
Trigonometric parallaxes with increasing precision allow us to
measure distances to rare objects such as planetary nebulae with
distances of hundreds of parsecs. The long-standing uncertain distance
scale of PNe is being addressed with these parallaxes -- now 16 PNe have
significant parallaxes, although most are small (only a few mas). To
turn high precision into high accuracy, the distances of reference stars
must be determined with spectrophotometry. Photometry has already been
obtained, but spectra are needed to resolve ambiguities by making
spectroscopic temperature and luminosity classifications using strengths
of established spectral features. We propose to use Hydra to acquire
spectra of reference stars around 9 PNe, 4 Cataclysmic Variables, and 2
other peculiar variables. These objects all have small parallaxes and
have reference stars that need better accuracy to match the parallax
precision and improve the accuracy of the final distance determinations.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2007A-0454 |
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