Alpha Coronae Borealis

Alpha Coronae Borealis
Location of α Coronae Borealis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Corona Borealis
Right ascension 15h 34m 41.268s[1]
Declination +26° 42′ 52.89″[1]
Apparent magnitude (V) 2.24[2]
Characteristics
Spectral type A0V + G5V[3]
U−B color index −0.03[4]
B−V color index −0.02[4]
Variable type Eclipsing binary[5]
Astrometry
Radial velocity (Rv)+1.7[6] km/s
Proper motion (μ) RA: 120.27[1] mas/yr
Dec.: −89.58[1] mas/yr
Parallax (π)43.46 ± 0.28 mas[1]
Distance75.0 ± 0.5 ly
(23.0 ± 0.1 pc)
Absolute magnitude (MV)+0.16/+5.05[3]
Orbit
Period (P)17.3599 d[7]
Semi-major axis (a)0.19379(50) AU[8]
Eccentricity (e)0.3794(19)[8]
Inclination (i)88.2 ± 0.1[7]°
Periastron epoch (T)56,646±0 (JD)[8]
Argument of periastron (ω)
(secondary)		312.32±0.43[8]°
Semi-amplitude (K1)
(primary)		36.22±0.13[8] km/s
Semi-amplitude (K2)
(secondary)		98.02±0.33[8] km/s
Details
α CrB A
Mass2.58[3] M☉
Radius2.89–3.04[3][7] R☉
Luminosity74[3] L☉
Surface gravity (log g)3.89[3] cgs
Temperature9,700[3] K
Rotational velocity (v sin i)139[9] km/s
Age0.314 Gyr
α CrB B
Mass0.92[3] M☉
Radius0.90[3][7] R☉
Luminosity0.81[3] L☉
Surface gravity (log g)4.50[3] cgs
Temperature5,800[3] K
Rotational velocity (v sin i)< 14[7] km/s
Other designations
Gemma, Alphecca, Ashtaroth, Gnosia Stella Coronae, 5 CrB, BD +27°2512, GCTP 3519.00, FK5 578, HD 139006, HIP 76267, HR 5793, SAO 83893.
Database references
SIMBADdata

Alpha Coronae Borealis (α Coronae Borealis, abbreviated Alpha CrB, α CrB), officially named Alphecca /ælˈfɛkə/,[10] is an eclipsing binary star in the constellation of Corona Borealis. It is located about 75 light years from the Sun and contains two main sequence stars, one class A and one class G.

  1. ^ a b c d e Cite error: The named reference van Leeuwen2007 was invoked but never defined (see the help page).
  2. ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ a b c d e f g h i j k l Cite error: The named reference aj91 was invoked but never defined (see the help page).
  4. ^ a b Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  5. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference GCSRV was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference aaa403 was invoked but never defined (see the help page).
  8. ^ a b c d e f Cite error: The named reference schmitt was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Royer was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference IAU-CSN was invoked but never defined (see the help page).