TW Piscis Austrini
From Wikipedia, the free encyclopedia
| 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[1] mas |
| Distance | 24.8 ± 0.1 ly (7.61 ± 0.04 pc) |
| Absolute magnitude (MV) | 7.07 |
| Details | |
| Mass | 0.725 ± 0.036[3] M☉ |
| Radius | 0.629 ± 0.051[3] R☉ |
| Luminosity | 0.12 L☉ |
| Temperature | 3,626[3] K |
| Rotational velocity (v sin i) | 2.93[3] km/s |
| Age | 2 × 108 years |
| Other designations | |
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 ten-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,[5] and the two may be travelling companions that share a common motion through space.
[edit] References
- ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, 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. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GJ+879&submit=SIMBAD+search. 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, 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.
- ^ 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.
[edit] External links
- ARICNS entry
- TW Piscis Austrini at SolStation.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||
