TW Piscis Austrini

from Wikipedia, the free encyclopedia
Star
TW Piscis Austrini
DSS image of the star field around Fomalhaut (sky section of almost 3 degrees)
DSS image of the star field around Fomalhaut (sky section of almost 3 degrees)
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Southern fish
Right ascension 22 h 56 m 24.05 s
declination -31 ° 33 ′ 56 ″
Apparent brightness (6.44 to 6.51) mag
Typing
B − V color index (1.1) 
Spectral class K4 Ve
Variable star type BY 
Astrometry
Radial velocity (+7.217 ± 0.0051) km / s
parallax (131.44 ± 0.09)  mas
distance (24.8)  ly
(7.60)  pc
Proper movement 
Rec. Share: (+329.58 ± 0.12)  mas / a
Dec. portion: (−158.29 ± 0.10)  mas / a
Physical Properties
Dimensions (0.757 ± 0.038)  M ☉
radius (0.743 ± 0.037)  R ☉
Luminosity

(0.19)  L ☉

Effective temperature (4711 ± 134)  K.
Age (440 ± 40) mill.  A
Other names
and catalog entries
Bayer name α Piscis Austrini B
Cordoba Survey CD −32 ° 17321
Bright Star Catalog HR 8721 [1]
Henry Draper Catalog HD 216803 [2]
Gliese catalog FY 879 [3]
Hipparcos catalog HIP 113283 [4]
SAO catalog SAO 214197 [5]
Tycho catalog TYC 7505-100-1 [6]
2MASS catalog 2MASS J22562403-3133559 [7]
Other names Fomalhaut B

TW Piscis Austrini (also Fomalhaut B ) is a main sequence star of the spectral class K at a distance of about 25  light years . He is the companion of Fomalhaut A . The star should not be confused with the exoplanet Fomalhaut b , which orbits Fomalhaut A at a great distance.

properties

The star belongs to the rotationally variable BY-Draconis stars and has a period of brightness fluctuations of 10.3 days. Luyten had already suspected that the star was gravitationally bound to Fomalhaut A since 1938 , but could only be confirmed in a relatively short time. Although the star is much less luminous than Fomalhaut A, its close proximity to the solar system means it is still bright enough to appear in the Bright Star catalog .

Web links

Individual evidence

  1. ↑ a b c d e f g TW PsA. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed April 20, 2019 .
  2. ↑ a b TW PsA. In: VSX. AAVSO , accessed April 20, 2019 .
  3. ↑ a b P. E. Kervella, F. Arenou, F. Mignard, F. Thévenin: Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly . In: Astronomy & Astrophysics . 623, p. A72. arxiv : 1811.08902 . bibcode : 2019A & A ... 623A..72K . doi : 10.1051 / 0004-6361 / 201834371 .
  4. ↑ a b E.E. Mamajek: On the Age and Binarity of Fomalhaut . In: Astrophysical Journal Letters . 754, No. 2, August 2012, p. L20. arxiv : 1206.6353 . bibcode : 2012ApJL..754 ... 20M . doi : 10.1088 / 2041-8205 / 754/2 / L20 .
  5. ↑ B.-O. Demory, D. Ségransan, T. Forveille, D. Queloz, J.-L. Beuzit, X. Delfosse, E. di Folco, P. Kervella, J.-B. Le Bouquin: Mass-radius relation of low and very low-mass stars revisited with the VLTI . In: Astronomy & Astrophysics . 505, No. 1, October 2009, pp. 205-215. arxiv : 0906.0602 . bibcode : 2009A & A ... 505..205D . doi : 10.1051 / 0004-6361 / 200911976 .
  6. ^ Willem J. Luyten: Note on a possible companion to Fomalhaut and some other pairs of stars . In: The Astronomical Journal . 47, No. 1090, 1938, pp. 115-116. bibcode : 1938AJ ..... 47..115L . doi : 10.1086 / 105490 .
  7. ↑ Eric E. Mamajek, Jennifer L. Bartlett, Andreas Seifahrt, Todd J. Henry, Sergio B. Dieterich, John C. Lurie, Matthew A. Kenworthy, Wei-Chun Jao, Adric R. Riedel, John P. Subasavage, Jennifer G. Winters, Charlie T. Finch, Philip A. Ianna, Jacob Bean: The Solar Neighborhood. XXX. Fomalhaut C . In: The Astronomical Journal . 146, No. 6, 2013, p. 154. arxiv : 1310.0764 . bibcode : 2013AJ .... 146..154M . doi : 10.1088 / 0004-6256 / 146/6/154 .