Astronomy:Ross 548

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Short description: Variable star in the constellation Cetus
Ross 548
ZZCetLightCurve.png
A light curve for ZZ Ceti, adapted from Stover et al. (1980)[1]
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Cetus
Right ascension  01h 36m 13.61558s[2]
Declination −11° 20′ 32.6318″[2]
Apparent magnitude (V) 14.16±0.01[3]
Characteristics
Evolutionary stage White dwarf
Spectral type DA4.0[4]
U−B color index −0.5[5]
B−V color index 0.2[5]
Variable type ZZ Cet (DAV)[5]
Astrometry
Proper motion (μ) RA: +460.845[2] mas/yr
Dec.: −116.448[2] mas/yr
Parallax (π)30.5249 ± 0.0546[2] mas
Distance106.8 ± 0.2 ly
(32.76 ± 0.06 pc)
Absolute magnitude (MV)11.78±0.06[6]
Details[6]
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[7]
Database references
SIMBADdata

Ross 548 is a white dwarf in the equatorial constellation of Cetus.[7] With a mean apparent visual magnitude of 14.2[3] 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.[2] It was found to be variable in 1970[8] and in 1972 it was given the variable star designation ZZ Ceti.[9] This is a pulsating white dwarf of the DAV type that is the prototype of the ZZ Ceti variable class.[10], pp. 891, 895.[3]

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.[6] The dominant pulsation mode of this object has a period of 213.1326 seconds. It has up to 11 known pulsation modes in total.[3]

References

  1. ↑ Stover, R. J.; Hesser, James E.; Lasker, Barry M.; Nather, R. E.; Robinson, E. L. (September 1980). "Period stability of the pulsating white dwarf R 548 (=ZZ Ceti)". The Astrophysical Journal 240: 865–870. doi:10.1086/158300. Bibcode: 1980ApJ...240..865S. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 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. doi:10.1088/0004-637X/815/1/56. 56. Bibcode: 2015ApJ...815...56G. 
  4. ↑ Gianninas, A. et al. (December 2011). "A Spectroscopic Survey and Analysis of Bright, Hydrogen-rich White Dwarfs". The Astrophysical Journal 743 (2): 27. doi:10.1088/0004-637X/743/2/138. 138. Bibcode: 2011ApJ...743..138G. 
  5. ↑ 5.0 5.1 5.2 McCook, George P.; Sion, Edward M. (March 1999). "A Catalog of Spectroscopically Identified White Dwarfs". Astrophysical Journal Supplement 121 (1): 1–130. doi:10.1086/313186. Bibcode: 1999ApJS..121....1M.  CDS ID III/210.
  6. ↑ 6.0 6.1 6.2 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. doi:10.3847/0067-0049/223/1/10. 10. Bibcode: 2016ApJS..223...10G. 
  7. ↑ 7.0 7.1 "ZZ Cet". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ZZ+Cet. 
  8. ↑ Lasker, Barry M.; Hesser, James E. (February 1971). "High-Frequency Stellar Oscillations. VI. R548, a Periodically Variable White Dwarf". Astrophysical Journal 163: L89–L93. doi:10.1086/180673. Bibcode: 1971ApJ...163L..89L. 
  9. ↑ Kukarkin, B. V. et al. (September 21, 1972). "58th Name-List of Variable Stars". Information Bulletin on Variable Stars 717: 1. Bibcode: 1972IBVS..717....1K. 
  10. ↑ Koester, D.; Chanmugam, G. (1990). "Physics of white dwarf stars". Reports on Progress in Physics 53 (7): 837–915. doi:10.1088/0034-4885/53/7/001. Bibcode: 1990RPPh...53..837K. 

Coordinates: Sky map 01h 36m 13.60s, −11° 20′ 32.2″



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