Upsilon2 Eridani

For other star systems with this Bayer designation, see Upsilon Eridani.
υ2 Eridani
Location of υ2 Eridani (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Eridanus
Right ascension 04h 35m 33.03834s[1]
Declination −30° 33′ 44.4297″[1]
Apparent magnitude (V) 3.804[2]
Characteristics
Spectral type G8+ III[3]
U−B color index +0.740[2]
B−V color index +0.968[2]
Astrometry
Radial velocity (Rv)−4.0±0.9[4] km/s
Proper motion (μ) RA: −49.27[1] mas/yr
Dec.: −12.72[1] mas/yr
Parallax (π)15.25 ± 0.19 mas[1]
Distance214 ± 3 ly
(65.6 ± 0.8 pc)
Absolute magnitude (MV)−0.27[5]
Details
Radius16[6] R☉
Luminosity138[7] L☉
Surface gravity (log g)2.77±0.07[8] cgs
Temperature5,074±30[8] K
Metallicity [Fe/H]0.04±0.03[8] dex
Other designations
Theemin, υ2 Eridani, Upsilon2 Eridani, 52 Eridani, CD −30° 1901, CPD−30 631, FK5 170, GC 5614, HD 29291, HIP 21393, HR 1464, PPM 280424, SAO 195148.[9]
Database references
SIMBADdata

Upsilon2 Eridani (υ² Eridani, abbreviated Upsilon2 Eri, υ2 Eri), officially named Theemin /ˈθiːmən/,[10][11] is a star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.8.[2] Based upon parallax measurements obtained during the Hipparcos mission,[1] it is approximately 66 parsecs (214 light-years) from the Sun.

It is an evolved red clump[12] giant star with a stellar classification of G8+ III.[3] The measured angular diameter is 2.21 mas.[13] At the star's distance, this yields a physical size of around 16 times the radius of the Sun.[6] It radiates 138[7] times the solar luminosity from its outer atmosphere at an effective temperature of 5074 K.[8]

  1. ^ a b c d e f 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 Gutierrez-Moreno1966 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Alves2015 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. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  11. ^ "Naming Stars". IAU.org. Retrieved 16 December 2017.
  12. ^ Cite error: The named reference Alves2000 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Richichi2005 was invoked but never defined (see the help page).