Delta Equulei

Delta Equulei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Equuleus
Right ascension 21h 14m 28.81531s[1]
Declination +10° 00′ 25.1259″[1]
Apparent magnitude (V) 5.19 + 5.52[2]
Characteristics
Spectral type F7V + F7V[3]
U−B color index −0.03[4]
B−V color index +0.49[4]
Astrometry
Radial velocity (Rv)−16.2±0.3[5] km/s
Proper motion (μ) RA: +42.39[1] mas/yr
Dec.: −304.19[1] mas/yr
Parallax (π)54.89 ± 0.50 mas[1]
Distance59.4 ± 0.5 ly
(18.2 ± 0.2 pc)
Absolute magnitude (MV)+3.14[6]
Orbit[7]
Period (P)2,084.03±0.10 d
Semi-major axis (a)231.9650±0.0080 mas
Eccentricity (e)0.436851±0.000025
Inclination (i)99.4083±0.0098°
Longitude of the node (Ω)23.362±0.012°
Periastron epoch (T)53112.071±0.052 MHJD
Argument of periastron (ω)
(secondary)		7.735±0.013°
Details
δ Equ A
Mass1.192±0.012[7] M☉
Radius1.30±0.08[3] R☉
Luminosity2.25[3] L☉
Temperature6,200±150 K
Metallicity [Fe/H]−0.07±0.09[3] dex
Age3.0[5] Gyr
δ Equ B
Mass1.187±0.012[7] M☉
Radius1.25±0.08[3] R☉
Luminosity2.07[3] L☉
Temperature6,200±150[3] K
Other designations
δ Equ, 7 Equulei, BD+09° 4746, GJ 822.0, HD 202275, HIP 104858, HR 8123, LTT 16227, SAO 126643.[8]
Database references
SIMBADdata

Delta Equulei, Latinized from δ Equulei, is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away,[9] with components of class G0 and F5.[10] Their combined magnitude is 4.47, and their absolute magnitude is 3.142. There is controversy as to the exact masses of the stars. One study puts the larger at 1.22 solar masses and the smaller at 1.17, while another pegs them at 1.66 and 1.593.[10] The luminosity of the larger star is calculated to be 2.23 solar, and the smaller to be 2.17.[10]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Malkov2012 was invoked but never defined (see the help page).
  3. ^ a b c d e f g Cite error: The named reference Torres2010 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Muterspaugh2008 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 Muterspaugh2005 was invoked but never defined (see the help page).
  10. ^ a b c "Delta Equulei". University of Illinois Astronomy department. Archived from the original on 2006-12-16.