Phi Leonis

φ Leonis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Leo
Right ascension 11h 16m 39.69960s[1]
Declination −03° 39′ 05.7770″[1]
Apparent magnitude (V) 4.46[2]
Characteristics
Spectral type A7 IVn[3]
U−B color index +0.10[2]
B−V color index +0.22[2]
Astrometry
Radial velocity (Rv)−3.0[4] km/s
Proper motion (μ) RA: −110.37[1] mas/yr
Dec.: −37.16[1] mas/yr
Parallax (π)17.71 ± 0.25 mas[1]
Distance184 ± 3 ly
(56.5 ± 0.8 pc)
Absolute magnitude (MV)0.56[5]
Details
Mass1.59[6] M☉
Radius2.9[7] R☉
Luminosity39[8] L☉
Surface gravity (log g)3.56[3] cgs
Temperature7,680±261[3] K
Rotational velocity (v sin i)254[3] km/s
Age432[3] Myr
Other designations
φ Leo, 74 Leo, BD−02°3315, FK5 1292, HD 98058, HIP 55084, HR 4368, SAO 138102[9]
Database references
SIMBADdata

Phi Leonis (φ Leo) is a single[10] star in the constellation Leo. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of 4.46.[2] Based upon parallax measurements,[1] the distance to Phi Leo is around 184 light years.

The spectrum of this star fits a stellar classification of A7IVn,[3] which suggests it is an A-type subgiant star that has left the main sequence and is evolving into a giant star. It is being viewed with the plane of the star's equator lying close the line of sight from the Earth,[11] and shows a high rotation rate with a projected rotational velocity of 254 km/s.[3] This rapid spin is giving the star an oblate shape with an equatorial bulge that is 29% larger than the polar radius.[12]

Phi Leonis has been mentioned as a shell star—indicating that there is a circumstellar disk of gas around the star's equator—and may display a slight variability.[5] Sporadic variation of the spectra on the time scale of minutes up to months in duration suggests that solid, cometary bodies are in orbit around the star, with objects approaching close enough for refractory materials to sublimate.[11] Most exocomet hosts do have a circumstellar disk, which can act as an exocomet reservoir. Cold dust around Phi Leonis was not detected, and the star is not associated with a warm debris disk.[13]

  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 c d e f g Cite error: The named reference Royer2007 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Wielen1999 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference aaa354_157 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference David2015 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference cadars 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 SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Hutter was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Eiroa was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference aar20_1_51 was invoked but never defined (see the help page).
  13. ^ Cataldi, Gianni; Moór, Attila; Ohashi, Nagayoshi; Eiroa, Carlos; Grady, Carol; Rebollido, Isabel (2019-02-22). "No Detection of Cold Dust around the Potential Exocomet Host ϕ Leo". Research Notes of the AAS. 3 (2): 39. Bibcode:2019RNAAS...3...39C. doi:10.3847/2515-5172/ab082b. ISSN 2515-5172. S2CID 127680980.