21 Canum Venaticorum

21 Canum Venaticorum
Observation data
Epoch J2000      Equinox J2000
Constellation Canes Venatici
Right ascension 13h 18m 14.50967s[1]
Declination +49° 40′ 55.4245″[1]
Apparent magnitude (V) +5.14[2]
Characteristics
Spectral type B9 IV (Si)[3] or A0 V Si:[4]
B−V color index −0.049±0.002[2]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)−2.9±2.8[2] km/s
Proper motion (μ) RA: −35.235[1] mas/yr
Dec.: +16.655[1] mas/yr
Parallax (π)11.7559 ± 0.1344 mas[1]
Distance277 ± 3 ly
(85.1 ± 1.0 pc)
Absolute magnitude (MV)0.48[6]
Details
Mass2.73[7] M☉
Radius2.8±0.3[6] R☉
Luminosity72.49[2] L☉
Surface gravity (log g)4.05[7] cgs
Temperature11,036±375[7] K
Rotational velocity (v sin i)96[7] km/s
Age201[7] Myr
Other designations
21 CVn, BK Canum Venaticorum, BD+50° 1994, FK5 3063, HD 115735, HIP 64906, HR 5023, SAO 44556[8]
Database references
SIMBADdata

21 Canum Venaticorum is a single[9] variable star[5] in the northern constellation of Canes Venatici, located 277 light years away from the Sun.[1] This object has the variable star designation BK Canum Venaticorum; 21 Canum Venaticorum is the Flamsteed designation. It is visible to the naked eye as a faint white-hued star with a baseline apparent visual magnitude of +5.14.[2]

According to Garrison et al. (1994)[3] this is a B-type subgiant star with a stellar classification of B9 IV (Si), where the suffix notation indicates this is a Silicon star. Cowley et al. (1969) listed it with a class of A0 V Si:,[4] which would match an A-type main-sequence star with the ':' indicating some uncertainty in the classification. It is a marginally chemically-peculiar star[10] with weaker than normal helium absorption lines and displaying helium line variability.[11] The widths of the lines of ionized silicon vary with a period of 21.12 ± 0.48 hours.[12]

21 Canum Venaticorum is classified as an Alpha2 Canum Venaticorum type variable star and its brightness varies by 0.04 magnitudes over a period of 18.4 hours.[5] Its variability was discovered in 1984 by Juraj Zverko[13] and it was given its variable star designation in 1987.[14] It is around 201 million years old and is spinning with a relatively high projected rotational velocity of 96 km/s.[7] The star has 2.73[7] times the mass of the Sun and 2.8[6] times the Sun's radius. It is radiating 72[2] times the luminosity of the Sun from its photosphere at an effective temperature of 11,036 K.[7]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference garrison1994 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference North1998 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Zverko1994 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Zverko1984 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Sriraghavan2004 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Zverko was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Kholopov was invoked but never defined (see the help page).