TW Piscis Austrini
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Piscis Austrinus |
| Right ascension | 22h 56m 24.05327s[1] |
| Declination | −31° 33′ 56.0351″[1] |
| Apparent magnitude (V) | 6.48[2] |
| Characteristics | |
| Spectral type | K5Vp[3] |
| U−B color index | 1.02[4] |
| B−V color index | 1.10[4] |
| Variable type | BY Draconis |
| Astrometry | |
| Radial velocity (Rv) | +6[2] km/s |
| Proper motion (μ) | RA: −331.11[1] mas/yr Dec.: −158.98[1] mas/yr |
| Parallax (π) | 131.42 ± 0.62 mas[1] |
| Distance | 24.8 ± 0.1 ly (7.61 ± 0.04 pc) |
| Absolute magnitude (MV) | 7.08[5] |
| Details | |
| Mass | 0.725 ± 0.036[3] M☉ |
| Radius | 0.629 ± 0.051[3] R☉ |
| Luminosity | 0.19[5] L☉ |
| Temperature | 4,711 ± 134[3] K |
| Rotational velocity (v sin i) | 2.93[3] km/s |
| Age | 4.4 × 108[5] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.9 light years.
The TW in the name is astronomical nomenclature for a variable star. This is a flare star of the type known as a BY Draconis variable. It varies slightly in apparent magnitude, ranging from 6.44 to 6.49 over a 10.3 day period. While smaller than the Sun, it is relatively large for a flare star. Most flare stars are red M-type dwarfs.
TW Piscis Austrini lies within a light year of the much brighter star Fomalhaut,[6] and the two may be travelling companions that share a common motion through space.
A 2012 study[5] showed that TW PsA and Fomalhaut are approximately only 0.28 parsecs (57,000 AU) apart, and share a space velocity within 0.1±0.5 km/s, consistent with constituting a physical binary system. Independent age estimates for Fomalhaut and TW PsA yield similar results, and the age for the system is 440±40 million years.[5]
In 2019 NASA's Transiting Exoplanet Survey Satellite space telescope found a exoplanet candidate around Fomalhaut B.[7][8]
References
- ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- ^ a b "V* TW PsA -- Variable of BY Dra type". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-01-20.
- ^ a b c d e Demory, B.-O.; et al. (October 2009), "Mass-radius relation of low and very low-mass stars revisited with the VLTI", Astronomy and Astrophysics, 505 (1): 205–215, arXiv:0906.0602, Bibcode:2009A&A...505..205D, doi:10.1051/0004-6361/200911976
- ^ a b Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99). Bibcode:1966CoLPL...4...99J.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b c d e Mamajek, E.E. (August 2012). "On the Age and Binarity of Fomalhaut". Astrophysical Journal Letters. 754 (2): L20. arXiv:1206.6353. Bibcode:2012ApJL..754...20M. doi:10.1088/2041-8205/754/2/L20.
- ^ p. 237, The Brightest Stars: Discovering The Universe Through The Sky's Most Brilliant Stars, Fred Schaaf, Hoboken, NJ: John Wiley & Sons, Inc., 2008, ISBN 978-0-471-70410-2.
- ^
Joe Rao (2019-09-23). "Fomalhaut, 'Royal' Star of Autumn, Swims with the Southern Fish". Space magazine. Retrieved 2020-06-13.
Believe it or not, an extrasolar planet might also be circling TW Piscis Austrini. NASA's Transiting Exoplanet Survey Satellite (TESS), a space telescope that's searching for planets around the brightest stars in Earth's night sky, recently found a possible candidate circling this star. It's almost the same size as our Earth, and orbits the star about every 10 days at a distance of 7.5 million miles from it.
{{cite news}}: CS1 maint: url-status (link)
External links
- TW Piscis Austrini at SolStation.
