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RE 0044+09: A new K dwarf rapid rotator with a white dwarf companion
We report the discovery of a new K dwarf rapid rotator with a potentialwhite dwarf companion. The white dwarf accounts for over 90% of theobserved extreme ultraviolet flux detected from this system. Analysis ofROSAT Wide Field Camera (WFC) and IUE data both suggest a white dwarftemperature of approximately 28,700 K. Optical photometry and the IUElong wavelength prime (LWP) spectrum (with the white dwarf contributionremoved) 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 SWPflux, and the best-fit temperature results in a white dwarf radius of0.0088 solar radius. The estimated white dwarf mass is thenapproximately 0.91 solar mass; somewhat over-massive compared to fieldwhite 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 significantvariations. Spectroscopic observations place a low limit on the lithiumabundance, 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 evolutionaryscenario is that the K star and hot white dwarf from either a widebinary or common proper motion pair with an age of 0.1-0.1Gyr-consistent with the evolutionary timescale of the white dwarf andthe rapid rotation of the K star. However, from the proper motion of theK star, this system does not seem to be associated with any of the knownyoung stellar groups.
| Photoelectric measurements of lunar occultation. VI. Further observational results.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973AJ.....78..482D&db_key=AST
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