Phi Eridani

φ Eridani
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Eridanus
Right ascension 02h 16m 30.58563s[1]
Declination −51° 30′ 43.7955″[1]
Apparent magnitude (V) 3.55[2]
Characteristics
Spectral type B8IV-V[3]
U−B color index −0.38[2]
B−V color index −0.12[2]
Astrometry
Radial velocity (Rv)10.40[4] km/s
Proper motion (μ) RA: +91.03[1] mas/yr
Dec.: −22.23[1] mas/yr
Parallax (π)21.22 ± 0.12 mas[1]
Distance153.7 ± 0.9 ly
(47.1 ± 0.3 pc)
Absolute magnitude (MV)0.183±0.027[5]
Details
Mass3.55[6] M☉
Radius3.4[7] R☉
Luminosity255[8] L☉
Surface gravity (log g)4.21±0.14[6] cgs
Temperature13,716±466[6] K
Rotation0.343705[9] d
Rotational velocity (v sin i)250[10] km/s
Age44[6] Myr
Other designations
φ Eri, CPD−52° 285, FK5 82, HD 14228, HIP 10602, HR 674, SAO 232696[11]
Database references
SIMBADdata

φ Eridani (Latinised as Phi Eridani) is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.55.[2] The distance to this star, as determined using the parallax method, is around 154 light-years.[1]

This is a B-type star with a stellar classification of B8IV-V,[3] suggesting it shows traits of a main-sequence star and a subgiant. It is spinning rapidly with a projected rotational velocity of 250 km/s. This rotation is giving the star an oblate shape with an equator that is 17% larger than the polar radius. The estimated angular size is 0.68 milliarcseconds.[10] Since the distance is known, this yields a physical size of around 3.4 times the radius of the Sun.[7] It has 3.55 times the mass of the Sun and radiates 255 times the solar luminosity from its outer atmosphere at an effective temperature of about 13,716 K.[6]

Phi Eridani may form a wide binary star system with a 9th-magnitude star at lies an angular separation of 86″. This companion is a G-type main-sequence star with a stellar classification of G2V.[12] It may also have a physical association with the naked-eye star Eta Horologii.[13] It is a member of the Tucana-Horologium association, a 45(±4)-Myr-old group of stars that share a common motion through space.[5]

  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 Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Zuckerman2004 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. ^ a b Cite error: The named reference Bell2015 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference David2015 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Barraza was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference vanBelle2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Shaya2011 was invoked but never defined (see the help page).