Sigma Andromedae

Sigma Andromedae
Location of σ Andromedae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Andromeda
Right ascension 00h 18m 19.65737s[1]
Declination +36° 47′ 06.8085″[1]
Apparent magnitude (V) +4.51[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A2 V[4]
U−B color index +0.07[5]
B−V color index +0.05[5]
Astrometry
Radial velocity (Rv)–8.0[2] km/s
Proper motion (μ) RA: −65.212(153)[1] mas/yr
Dec.: −42.221(124)[1] mas/yr
Parallax (π)23.2542 ± 0.1809 mas[1]
Distance140 ± 1 ly
(43.0 ± 0.3 pc)
Absolute magnitude (MV)1.33[6]
Details
Mass2.12±0.01[3] M☉
Radius2.13[7] R☉
Luminosity21.23[7] L☉
Surface gravity (log g)4.02[6] cgs
Temperature8,929[6] K
Rotational velocity (v sin i)123[8] km/s
Age450[7] Myr
Other designations
σ And, 25 Andromedae, BD+35°44, FK5 1005, HD 1404, HIP 1473, HR 68, SAO 53798, PPM 65183[9]
Database references
SIMBADdata

Sigma Andromedae, Latinized from σ Andromedae, is the Bayer designation for a single[10] star in the northern constellation of Andromeda. It has an apparent visual magnitude of +4.5,[2] which is bright enough to be seen with the naked eye from most locations. Parallax measurements made during the Gaia mission place it at a distance of about 140 light-years (43 parsecs).[1] The magnitude of the star is diminished by 0.08 from extinction caused by intervening gas and dust.[11] It is drifting closer to the Sun with a radial velocity of –8 km/s.[2]

This star has a stellar classification of A2 V,[4] which matches the spectrum of an A-type main sequence star. It is about 450 million years old[12] and is spinning rapidly with a projected rotational velocity of 123 km/s.[8] The star has 2.12[3] times the mass of the Sun and 2.13[7] times the Sun's girth. It is radiating 21[7] times the luminosity of the Sun from its photosphere at an effective temperature of 8,929 K,[6] giving it the white-hued glow of an A-type star.[13]

In the past, radial velocity variations have been reported,[14] but this remains unconfirmed.[10] The star does not show any significant photometric variations and is used as an ubvy standard star.[15] A debris disk of warm dust around this star has been detected by Spitzer Space Telescope.[16][17] A model fit to the data yields an orbital distance of 20.3 AU from the host star with a mean temperature of 132.9 K.[7]

Sigma Andromedae is a candidate for membership in the stream of stars associated with the Ursa Major Moving Group. This is a set of stars that share a common motion through space, which suggests they originated together.[6]

  1. ^ a b c d e f Cite error: The named reference Gaia EDR3 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference scfs was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Zorec_Royer_2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference aj74_375 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference aj125_4_1980 was invoked but never defined (see the help page).
  7. ^ a b c d e f Cite error: The named reference Gaspar_et_al_2016 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference aaa463_2_671 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. ^ a b Cite error: The named reference Eggleton_Tokovinin_2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference apjss176_1_276 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference aj143_6_135 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Lee1910 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference aaa300_783 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference apj699_2_2009 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Patel_et_al_2014 was invoked but never defined (see the help page).