Ross 548
Variable star in the constellation Cetus
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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]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| 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 mas[2] |
| Distance | 106.8 ± 0.2 ly (32.76 ± 0.06 pc) |
| Absolute magnitude (MV) | 11.78±0.06[6] |
| Details[6] | |
| Mass | 0.65±0.02 M☉ |
| Radius | 0.0118±0.0002 R☉ |
| Luminosity | 0.0029±0.0002 L☉ |
| Surface gravity (log g) | 8.108±0.025 cgs |
| Temperature | 12,281±125 K |
| Rotation | 37.84±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 | |
| SIMBAD | data |
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]