Ross 548

Ross 548 is a star in the equatorial constellation of Cetus.[6] With a mean apparent visual magnitude of 14.2[2] it is much too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of 107 light years from the Sun.[1] It was found to be variable in 1970[7] and in 1972 it was given the variable star designation ZZ Ceti.[8] This is a pulsating white dwarf of the DAV type that is the prototype of the ZZ Ceti variable class.[9], pp. 891, 895.[2]

Ross 548
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cetus
Right ascension 01h 36m 13.61558s[1]
Declination −11° 20′ 32.6318″[1]
Apparent magnitude (V) 14.16±0.01[2]
Characteristics
Evolutionary stage White dwarf
Spectral type DA4.0[3]
U−B color index −0.5[4]
B−V color index 0.2[4]
Variable type ZZ Cet (DAV)[4]
Astrometry
Proper motion (μ) RA: +460.845[1] mas/yr
Dec.: −116.448[1] mas/yr
Parallax (π)30.5249 ± 0.0546[1] mas
Distance106.8 ± 0.2 ly
(32.76 ± 0.06 pc)
Absolute magnitude (MV)11.78±0.06[5]
Details[5]
Mass0.65±0.02 M☉
Radius0.0118±0.0002 R☉
Luminosity0.0029±0.0002 L☉
Surface gravity (log g)8.108±0.025 cgs
Temperature12,281±125 K
Rotation37.84±1.99 h
Other designations
ZZ Cet, EGGR 10, G 271-106, G 272-52, LTT 873, NLTT 5358, WD 0133-116[6]
Database references
SIMBADdata

This DA-class white dwarf is the surviving core of a red giant star that ceased nuclear fusion while shedding its outer envelope. It has a (presumably) homogeneous core of carbon and oxygen, a relatively thin outer envelope of hydrogen, and a helium mantle. The object has 65% of the mass of the Sun, with 1.2% of the Sun's radius. It is radiating 0.3% of the luminosity of the Sun at an effective temperature of 12,281 K. Ross 548 is spinning with a period of ~38 hours.[5] The dominant pulsation mode of this object has a period of 213.1326 seconds. It has up to 11 known pulsation modes in total.[2]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Giammichele, N.; et al. (December 2015). "A New Analysis of the Two Classical ZZ Ceti White Dwarfs GD 165 and Ross 548. I. Photometry and Spectroscopy". The Astrophysical Journal. 815 (1): 12. Bibcode:2015ApJ...815...56G. doi:10.1088/0004-637X/815/1/56. 56.
  3. Gianninas, A.; et al. (December 2011). "A Spectroscopic Survey and Analysis of Bright, Hydrogen-rich White Dwarfs". The Astrophysical Journal. 743 (2): 27. arXiv:1109.3171. Bibcode:2011ApJ...743..138G. doi:10.1088/0004-637X/743/2/138. 138.
  4. McCook, George P.; Sion, Edward M. (March 1999). "A Catalog of Spectroscopically Identified White Dwarfs". Astrophysical Journal Supplement. 121 (1): 1–130. Bibcode:1999ApJS..121....1M. CDS ID III/210.
  5. Giammichele, N.; et al. (March 2016). "A New Analysis of the Two Classical ZZ Ceti White Dwarfs GD 165 and Ross 548. II. Seismic Modeling". The Astrophysical Journal Supplement Series. 223 (1): 27. Bibcode:2016ApJS..223...10G. doi:10.3847/0067-0049/223/1/10. 10.
  6. "ZZ Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-11-16.
  7. Lasker, Barry M.; Hesser, James E. (February 1971). "High-Frequency Stellar Oscillations. VI. R548, a Periodically Variable White Dwarf". Astrophysical Journal. 163: L89–L93. Bibcode:1971ApJ...163L..89L.
  8. Kukarkin, B. V.; et al. (September 21, 1972). "58th Name-List of Variable Stars". Information Bulletin on Variable Stars. 717. Bibcode:1972IBVS..717....1K.
  9. Koester, D.; Chanmugam, G. (1990). "Physics of white dwarf stars". Reports on Progress in Physics. 53: 837–915. Bibcode:1990RPPh...53..837K.

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