Tau2 Hydrae

For other stars with this Bayer designation, see τ Hydrae.
Tau2 Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 09h 31m 58.92729s[1]
Declination −01° 11′ 04.7899″[1]
Apparent magnitude (V) +4.56[2]
Characteristics
Spectral type A3 V[3]
U−B color index +0.06[2]
B−V color index +0.11[2]
Variable type Suspected[4]
Astrometry
Radial velocity (Rv)+3.9±0.4[5] km/s
Proper motion (μ) RA: −12.60[1] mas/yr
Dec.: −3.99[1] mas/yr
Parallax (π)6.30 ± 0.72 mas[1]
Distanceapprox. 520 ly
(approx. 160 pc)
Absolute magnitude (MV)−1.43[6]
Details
Radius4.5[7] R☉
Luminosity285[8] L☉
Temperature7,918[8] K
Rotational velocity (v sin i)54.0±0.6[3] km/s
Other designations
Ukdah, τ2 Hya, 32 Hydrae, BD−00°2211, HD 82446, HIP 46776, HR 3787, SAO 136932.[9]
Database references
SIMBADdata

Tau2 Hydrae is a probable astrometric binary[10] star system in the equatorial constellation of Hydra. Based upon an annual parallax shift of 6.30 mas as seen from Earth, it is located around 520 light years from the Sun. The brighter component is visible to the naked eye with an apparent visual magnitude of +4.56.[2]

The primary member, component A, is an A-type main sequence star with a stellar classification of A3 V.[3] It is a suspected variable of unknown type, with an amplitude of 0.06 in visual magnitude.[4] The star has around 4.5[7] times the radius of the Sun and is radiating about 285 times the solar luminosity from its photosphere at an effective temperature of 7,918 K.[8]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Diaz2011 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Adelman2000 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).