Delta Equulei

Delta Equulei

Observation data Epoch J2000      Equinox J2000
Constellation	Equuleus
Right ascension	21h 14m 28.8152s
Declination	+10° 00' 25.132"'
Apparent magnitude (V)	4.49 / 5.4
Characteristics
Spectral type	F5V+ / G0
U−B color index	-0.01
B−V color index	0.5
Variable type	None
Astrometry
Radial velocity (Rv)	-15.4 km/s
Proper motion (μ)	RA: 42.32 mas/yr Dec.: -303.43 mas/yr
Parallax (π)	54.11 ± 0.85 mas
Distance	60.3 ± 0.9 ly (18.5 ± 0.3 pc)
Absolute magnitude (MV)	4.99
Details
Mass	1.22 / 1.17 M☉
Radius	1.19 / 0.525 R☉
Luminosity	2.23 / 2.17 L☉
Age	1.6 - 2.8 billion years
Orbit
Companion	Delta Equulei B
Period (P)	5.7 yr
Semimajor axis (a)	0.26"
Eccentricity (e)	0.42
Inclination (i)	100°
Longitude of the node (Ω)	23°
Periastron epoch (T)	1912.77
Other designations
HD 202275, del Equ, LTT 16227, GJ 822.0, HIP 104858, BD+09° 4746, HR 8123, SAO 126643.
Database references
SIMBAD	data

Delta Equulei is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away,^[1] with components of class G0 and F5.^[2] 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.^[2] The luminosity of the larger star is calculated to be 2.23 solar, and the smaller to be 2.17.^[2]

References

1. ^ SkyGazer, College Edition, version 3.4
2. ^ ^{a b c} "Delta Equulei". University of Illinois Astronomy department. http://www.astro.uiuc.edu/~kaler/sow/deltaequ.html. 

External links

• "HD 202275 -- Star". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+202275. Retrieved 2007-01-22. 
• Delta Equulei