HD 12139

HD 12139
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 01h 59m 35.68394s[1]
Declination 21° 03′ 30.8472″[1]
Apparent magnitude (V) 5.89[2]
Characteristics
Spectral type K0III-IV[3]
B−V color index 1.031±0.015[2]
Astrometry
Radial velocity (Rv)−1.65±0.20[1] km/s
Proper motion (μ) RA: +141.014[1] mas/yr
Dec.: -14.643[1] mas/yr
Parallax (π)9.3049 ± 0.0967 mas[1]
Distance351 ± 4 ly
(107 ± 1 pc)
Absolute magnitude (MV)0.50[2]
Details
Mass1.69±0.48[4] M☉
Radius11.12+0.34
−0.13[1] R☉
Luminosity58.2±0.7[1] L☉
Surface gravity (log g)2.50±0.11[4] cgs
Temperature4,780+120
−70[1] K
Metallicity [Fe/H]−0.02±0.05[4] dex
Age2.0+1.0
−0.6[4] Gyr
Other designations
BD+20°322, HD 12139, HIP 9307, HR 577, SAO 75077, WDS J01596+2100D[5]
Database references
SIMBADdata

HD 12139 is an orange-hued star in the northern zodiac constellation of Aries. With an apparent visual magnitude of 5.89, it is a dim star that is just visible to the naked eye under good viewing conditions. It is located approximately 351 light-years (107.5 pc) distant from the Sun, based on parallax,[2] but is drifting closer with a radial velocity of −2 km/s.[1] With high probability, it is considered a member of the Hercules stream.[6]

This object is an aging red giant[7] with a stellar classification of K0III-IV,[3] meaning that it has used up its core hydrogen and is expanding. At present it has 11[1] times the girth of the Sun. The star is about two[4] billion years old with 1.7[4] times the mass of the Sun. It is radiating 58[1] times the luminosity of the Sun from its photosphere at an effective temperature of 4,780 K.[1]

A magnitude 9.36 companion is located at an angular separation of 199.70″ from the primary along a position angle of 9°, as of 2015. It is unclear if the two are physically associated.[8]

  1. ^ a b c d e f g h i j k l m Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Yoss1961 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Feuillet2016 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Ramya2016 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference takeda14 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).