NOAO >   Observing Info >   Approved Programs >   2001A-0033

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Proposal Information for 2001A-0033


PI: Paul J. Groot, Harvard-Smithsonian Center for Astroph., pgroot@cfa.harvard.edu
Address: 60 Garden Street, Cambridge, MA 02138, USA

CoI: Gijs Nelemans, University of Amsterdam, NL
CoI: Danny Steeghs, Southampton University, UK
CoI: Tom Marsh, Southampton University, UK

Title: A Mini-Survey to Discover AM CVn stars

Abstract: We propose a mini-survey to find new AM CVn stars. There are currently only seven systems known, mainly because of a lack of dedicated, deep searches. AM CVn systems are binaries where mass is transferred from a completely hydrogen-deficient, degenerate mass donor to a white dwarf primary through a helium accretion disk. A better understanding of these systems is crucial for a number of reasons: a) to study the late stages of binary evolution; b) to study the effect of chemical composition on the physics of accretion discs; c) to estimate their contribution to the Supernova Ia rate. For all of these studies it is imperative that we gain a better understanding of the total number of systems that are present at a given magnitude. Using a four filter (Sloan g^\prime, Sloan r^\prime, H(alpha), H(alpha)+120) observing technique we will identify them by their He\sc i 6678 Aemission. This is a fast and efficient way to cover a large part of the sky to a depth of R~22: 6 magnitudes deeper than current or past surveys. In 4 nights we will be able to cover ~20 sq.degr. of sky, which should result in 50-300 new AM CVn systems.


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