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RE 0044+09: A new K dwarf rapid rotator with a white dwarf companionWe report the discovery of a new K dwarf rapid rotator with a potential white dwarf companion. The white dwarf accounts for over 90% of the observed extreme ultraviolet flux detected from this system. Analysis of ROSAT Wide Field Camera (WFC) and IUE data both suggest a white dwarf temperature of approximately 28,700 K. Optical photometry and the IUE long wavelength prime (LWP) spectrum (with the white dwarf contribution removed) imply that the late-type star has a spectral type of K1-3 V, and a distance of 55 +/- 5 pc. Using this distance, the observed IUE SWP flux, and the best-fit temperature results in a white dwarf radius of 0.0088 solar radius. The estimated white dwarf mass is then approximately 0.91 solar mass; somewhat over-massive compared to field white dwarfs. Optical photometry of the K star reveals a 'spot' modulation period of approximately 10 hr (now observed over 3 yr). However, radial velocity observations have revealed no significant variations. Spectroscopic observations place a low limit on the lithium abundance, but do show rapid rotation with a v sin i of 90 +/- 10 km/s. The K star was detected as a radio source at 3.6 cm (on two occasions) and 6 cm by the Very Large Array (VLA). The most likely evolutionary scenario is that the K star and hot white dwarf from either a wide binary or common proper motion pair with an age of 0.1-0.1 Gyr-consistent with the evolutionary timescale of the white dwarf and the rapid rotation of the K star. However, from the proper motion of the K star, this system does not seem to be associated with any of the known young stellar groups.
Document ID
19950048259
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kellett, Barry J.
(Rutherford Appleton Lab. Chilton, United Kingdom)
Bromage, Gordon E.
(Univ. of Central Lancashire, Preston, Lancanshire United Kingdom)
Brown, Alexander
(Univ. of Colorado, Boulder, CO United States)
Jeffries, Robin D.
(Univ. of Birmingham Birmingham, United Kingdom)
James, David J.
(Univ. of Birmingham Birmingham, United Kingdom)
Kilkenny, David
(South African Astronomical Observatory Cape Town, South Africa)
Robb, Russell M.
(Univ. of Victoria, Victoria, BC United Kingdom)
Wonnacott, David
(Mullard Space Science Lab. Surrey, United Kingdom)
Lloyd, Christopher
(Rutherford Appleton Lab. Chilton, United Kingdom)
Clayton, C.
(Rutherford Appleton Lab. Chilton, United Kingdom)
Date Acquired
August 16, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 438
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A79858
Funding Number(s)
CONTRACT_GRANT: NAG5-1792
Distribution Limits
Public
Copyright
Other

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