NOAO > Observing Info > Approved Programs > 2006B-0417
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NOAO > Observing Info > Approved Programs > 2006B-0417 |
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PI: MICHAEL SHARA, Amer. Mus. Nat. History, MSHARA@AMNH.ORG
Address: ASTROPHYSICS, CPW at 79TH STREET, NEW YORK, NY 10024-5192, USA
CoI: DAVID ZUREK, AMNH
Title: Deep Narrowband Imagery of Z Cam - A Nova AND a Dwarf Nova
Abstract:
Cataclysmic variables (classical novae and dwarf novae) are binary
star systems in which a red dwarf transfers hydrogen-rich matter, via an
accretion disk, to its white dwarf companion. In dwarf novae, an
instability is believed to episodically dump much of the accretion disk
onto the white dwarf. The liberation of gravitational potential energy
then brightens these systems up to a hundred-fold every few weeks or
months. Thermonuclear-powered eruptions a thousand times more luminous
occur in classical novae, accompanied by significant mass ejection and
formation of clearly visible shells. Theory predicts that the white
dwarfs in all dwarf novae must eventually accrete enough mass to undergo
classical nova eruptions, but not a single dwarf nova has ever been
shown to have undergone a classical nova eruption. GALEX NUV+FUV
imagery shows the shell of the prototypical dwarf nova Z Cam to be an
order of magnitude more extended than any detected around any classical
nova. The derived shell mass (from KPNO spectroscopy) matches that of
classical novae, and is inconsistent with the mass expected from a
steady dwarf nova wind. Thus the shell mass and morphology
observationally link, for the first time, a dwarf nova with the
classical nova process. We are requesting 2 nights of 4 meter time to
determine the extent and morphology of the nova optical ejecta, and to
rule out possible contamination by interstellar cirrus.
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 > 2006B-0417 |
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