Alpha Serpentis

α Serpentis
Location of α Serpentis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 15h 44m 16.07431s[1]
Declination +06° 25′ 32.2633″[1]
Apparent magnitude (V) 2.623[2]
Characteristics
Evolutionary stage Horizontal branch[3]
Spectral type K2 IIIb CN1[4]
U−B color index +1.248[2]
B−V color index +1.167[2]
Astrometry
Radial velocity (Rv)+2.63[5] km/s
Proper motion (μ) RA: +133.84[1] mas/yr
Dec.: +44.81[1] mas/yr
Parallax (π)44.10 ± 0.19 mas[1]
Distance74.0 ± 0.3 ly
(22.68 ± 0.10 pc)
Absolute magnitude (MV)+0.88±0.03[6]
Details
Mass1.61±0.18[7] M☉
Radius12.19[8] R☉
Luminosity58.9±3[7] L☉
Surface gravity (log g)2.4[8] cgs
Temperature4,687±59[7] K
Metallicity [Fe/H]0.189[8] dex
Rotational velocity (v sin i)4.3[9] km/s
Age2.06±0.33[7] Gyr
Other designations
Unukalhai, Cor Serpentis, Alpha Ser, α Ser, 24 Serpentis, BD+06° 3088, HD 140573, HIP 77070, HR 5854, SAO 121157, ADS 9765, CCDM 15442+0626[10]
Database references
SIMBADdata

Alpha Serpentis or α Serpentis, formally named Unukalhai (/ˌjuːnək.ælˈheɪ/),[11][12] is a double star in the head (Serpens Caput) of the equatorial constellation of Serpens. With an apparent visual magnitude of 2.6,[2] this star is the brightest in the constellation and it can be viewed with the naked eye from most of the Earth. Parallax measurements yield an estimated distance of about 74 light-years (23 parsecs) from the Sun.

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference sps1966 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference kaler was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Keenan_McNeil_1989 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference aaa430_165 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference aj135_3_892 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference baines2018 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Gray_Kaur_2019 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aj135_1_209 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ 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.
  12. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.