Astronomy:TY Coronae Borealis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Corona Borealis |
| Right ascension | 16h 01m 23.187s[2] |
| Declination | +36° 48′ 34.29″[2] |
| Apparent magnitude (V) | 14.435±0.018[3] |
| Characteristics | |
| Evolutionary stage | White dwarf |
| Spectral type | DA4.4[4] |
| Variable type | ZZ Ceti[5] |
| Astrometry | |
| Proper motion (μ) | RA: 101.113[2] mas/yr Dec.: −545.353[2] mas/yr |
| Parallax (π) | 30.4668 ± 0.0187[2] mas |
| Distance | 107.05 ± 0.07 ly (32.82 ± 0.02 pc) |
| Absolute magnitude (MV) | +11.81[6] |
| Details | |
| Mass | 0.593±0.028 to 0.615+0.024 −0.025[3] M☉ |
| Radius | 0.0131±0.0014[7] R☉ |
| Luminosity | (1.83±0.03)×10−3[8] L☉ |
| Surface gravity (log g) | 8.194[9] cgs |
| Temperature | 11,000[9] K |
| Age | 447 (white dwarf stage)[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
TY Coronae Borealis, also known as Ross 808, is a white dwarf in the constellation Corona Borealis. It is 107 light-years distant from Earth,[2] and has a dim apparent magnitude of 14.4.[3]
It is a pulsating white dwarf of the DAV (ZZ Ceti) type. The variation in the blue band is of 0.14 magnitudes, over a period of 15 minutes.[5] It was confirmed as a variable star in 1976, and now has the variable-star designation TY Coronae Borealis.[10] Being of this variable class, it has been a target for asteroseismic analyses, in attempt to derive its physical properties such as mass, radius and gravity.[9][11][8] However, it seems estimations of the stellar mass derived for this star using asteroseismology had been overestimated.[3]
TY Coronae Borealis has around 0.6 times the mass of the Sun[3] and a tiny diameter of only 1.3% that of the Sun.[7] It is a dim star, with 0.2% of the Sun's luminosity.[8] It has an effective temperature of about 11,000 K,[9] have taken 450 million years to cool to its temperature. This is also its age as a white dwarf.[6]
References
- ↑ Bognár, Zs.; Paparó, M.; Sódor, Á.; Jenei, D. I.; Kalup, Cs.; Bertone, E.; Chavez-Dagostino, M.; Montgomery, M. H. et al. (January 2019). "Wandering near the red edge: photometric observations of three cool ZZ Ceti stars". Monthly Notices of the Royal Astronomical Society 482 (3): 4018–4031. doi:10.1093/mnras/sty2884. Bibcode: 2019MNRAS.482.4018B.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 Calcaferro, Leila M.; Córsico, Alejandro H.; Uzundag, Murat; Althaus, Leandro G.; Kepler, S. O.; Werner, Klaus (2024-11-01). "An analysis of spectroscopic, seismological, astrometric, and photometric masses of pulsating white dwarf stars" (in en). Astronomy & Astrophysics 691: A194. doi:10.1051/0004-6361/202450582. ISSN 0004-6361. Bibcode: 2024A&A...691A.194C.
- ↑ 4.0 4.1 "TY CrB". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=TY+CrB.
- ↑ 5.0 5.1 Watson, Christopher (4 January 2010). "TY Coronae Borealis". AAVSO Website. American Association of Variable Star Observers. http://www.aavso.org/vsx/index.php?view=detail.top&oid=10631. Retrieved 23 November 2014.
- ↑ 6.0 6.1 6.2 Limoges, M. -M.; Bergeron, P.; Lépine, S. (2015-08-01). "Physical Properties of the Current Census of Northern White Dwarfs within 40 pc of the Sun". The Astrophysical Journal Supplement Series 219 (2): 19. doi:10.1088/0067-0049/219/2/19. ISSN 0067-0049. Bibcode: 2015ApJS..219...19L.
- ↑ 7.0 7.1 Bédard, A.; Bergeron, P.; Fontaine, G. (2017-10-05). "Measurements of Physical Parameters of White Dwarfs: A Test of the Mass–Radius Relation". The Astrophysical Journal 848 (1): 11. doi:10.3847/1538-4357/aa8bb6. ISSN 0004-637X. Bibcode: 2017ApJ...848...11B.
- ↑ 8.0 8.1 8.2 Romero, A. D.; Córsico, A. H.; Althaus, L. G.; Kepler, S. O.; Castanheira, B. G.; Miller Bertolami, M. M. (2012-02-21). "Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models". Monthly Notices of the Royal Astronomical Society 420 (2): 1462–1480. doi:10.1111/j.1365-2966.2011.20134.x. ISSN 0035-8711. Bibcode: 2012MNRAS.420.1462R.
- ↑ 9.0 9.1 9.2 9.3 Chen, Y H; Shu, H (2021-02-01). "Asteroseismology of the DAV star R808". Monthly Notices of the Royal Astronomical Society 500 (4): 4703–4709. doi:10.1093/mnras/staa3572. ISSN 0035-8711.
- ↑ McGraw, John T.; Robinson, Edward L. (1976). "High-speed photometry of luminosity-variable DA dwarfs: R808, GD 99, and G 117-B15A". Astrophysical Journal Letters 205: L155-58. doi:10.1086/182112. Bibcode: 1976ApJ...205L.155M.
- ↑ Bischoff-Kim, Agnès; Bell, Keaton J. (2024-07-12). "Constraints from Parallaxes and Average Period Spacings in the Asteroseismic Study of Eight Hydrogen-atmosphere Pulsating White Dwarfs" (in en). The Astrophysical Journal 970 (1): 27. doi:10.3847/1538-4357/ad4edc. ISSN 0004-637X. Bibcode: 2024ApJ...970...27B.
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