Tau1 Eridani

For other star systems with this Bayer designation, see Tau Eridani.
τ1 Eridani
Observation data
Epoch J2000      Equinox J2000
Constellation Eridanus
Right ascension 02h 45m 06.18710s[1]
Declination −18° 34′ 21.2149″[1]
Apparent magnitude (V) 4.46[2]
Characteristics
Spectral type F7V[3]
U−B color index +0.00[2]
B−V color index +0.48[2]
Astrometry
Radial velocity (Rv)+25.9[4] km/s
Proper motion (μ) RA: +334.20[1] mas/yr
Dec.: +37.19[1] mas/yr
Parallax (π)70.32 ± 1.83 mas[1]
Distance46 ± 1 ly
(14.2 ± 0.4 pc)
Absolute magnitude (MV)+3.68[5]
Orbit[6]
Period (P)958 d
Eccentricity (e)0.45
Periastron epoch (T)39391.9
Argument of periastron (ω)
(secondary)		180°
Details
Mass1.15[7] M☉
Radius1.325[8] R☉
Luminosity2.572[8] L☉
Surface gravity (log g)4.34[9] cgs
Temperature6,357[8] K
Metallicity [Fe/H]−0.08 ± 0.06[9] dex
Rotation3.847 d[10]
Rotational velocity (v sin i)28.02[11] km/s
Other designations
1 Eri, BD−19°518, FK5 2075, GJ 111, HD 17206, HIP 12843, HR 818, SAO 11557[12]
Database references
SIMBADdata

Tau1 Eridani, Latinized from τ1 Eridani, is a binary star[6] system in the constellation Eridanus. It has an apparent magnitude of 4.46, making it visible to the naked eye in suitably dark conditions. This is a spectroscopic binary with an orbital period of 958 days.[6] It is located about 46 light years from the Earth.[1] At present, the system is moving away from the Sun with a radial velocity of +26 km/s.[4] About 305,000 years ago, perihelion passage was made at an estimated distance of 30.5 ly (9.35 pc).[13]

Tau1 Eridani was a latter designation of 90 Ceti.[14]

  1. ^ a b c d e f Cite error: The named reference aa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference MERMILLIOD was invoked but never defined (see the help page).
  3. ^ Abt, H. A. (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement Series. 180 (1): 117–118. Bibcode:2009ApJS..180..117A. doi:10.1088/0067-0049/180/1/117. S2CID 122811461.
  4. ^ a b Cite error: The named reference paas21_2_129 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Reiners2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference pdaov15_121 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference aj144_1_7 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference schofield was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference aaa420_183 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference rot_rate was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference aaa520_A79 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, S2CID 59039482, A35.
  14. ^ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 215. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID 118445625.