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Title: AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL

Abstract

We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of {approx}5 Multiplication-Sign 10{sup -5} M {sub Sun }, typical ofmore » classical novae.« less

Authors:
; ;  [1];  [2]; ; ;  [3];  [4]
  1. Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192 (United States)
  2. Steward Observatory, the University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Department of Physics, Math and Astronomy, California Institute of Technology, 1200 East California Boulevard, Mail Code 405-47, Pasadena, CA 91125 (United States)
  4. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22086501
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 758; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; DWARF STARS; EMISSION SPECTRA; FAR ULTRAVIOLET RADIATION; GALACTIC EVOLUTION; GALAXIES; ION EMISSION; NITROGEN IONS; NOVAE; ULTRAVIOLET SPECTRA

Citation Formats

Shara, Michael M., Mizusawa, Trisha, Zurek, David, Wehinger, Peter, Martin, Christopher D., Neill, James D., Forster, Karl, and Seibert, Mark. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL. United States: N. p., 2012. Web. doi:10.1088/0004-637X/758/2/121.
Shara, Michael M., Mizusawa, Trisha, Zurek, David, Wehinger, Peter, Martin, Christopher D., Neill, James D., Forster, Karl, & Seibert, Mark. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL. United States. doi:10.1088/0004-637X/758/2/121.
Shara, Michael M., Mizusawa, Trisha, Zurek, David, Wehinger, Peter, Martin, Christopher D., Neill, James D., Forster, Karl, and Seibert, Mark. Sat . "AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL". United States. doi:10.1088/0004-637X/758/2/121.
@article{osti_22086501,
title = {AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL},
author = {Shara, Michael M. and Mizusawa, Trisha and Zurek, David and Wehinger, Peter and Martin, Christopher D. and Neill, James D. and Forster, Karl and Seibert, Mark},
abstractNote = {We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of {approx}5 Multiplication-Sign 10{sup -5} M {sub Sun }, typical of classical novae.},
doi = {10.1088/0004-637X/758/2/121},
journal = {Astrophysical Journal},
number = 2,
volume = 758,
place = {United States},
year = {Sat Oct 20 00:00:00 EDT 2012},
month = {Sat Oct 20 00:00:00 EDT 2012}
}
  • A detailed model of white dwarf mass distribution in newly formed cataclysmic binaries produced by close binary evolution is presently used to derive the distributions for such systems' subsequent nova outbursts, in view of selection effects due to the dependences of envelope ignition mass, companion mass, and outburst luminosity on the masses of white dwarfs in nova systems. As much as 25-27 percent of observed nova outbursts should occur on O-Ne-Mg white dwarfs, with the rest occurring almost entirely on C-O white dwarfs. Some evidence of a bimodal character is noted in the empirical mass distribution for white dwarfs, asmore » anticipated by the models. 45 refs.« less
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