Delta Andromedae

δ Andromedae

Template:Location mark Location of δ Andromedae (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Andromeda
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	3.28
Characteristics
Spectral type	K3 III + K4 ± 2
U−B Template:Engvar	+1.48
B−V Template:Engvar	+1.28
R−I Template:Engvar	+0.66
Astrometry
Radial velocity (Rv)	Template:Val km/s
Proper motion (μ)	RA: +114.45 mas/yr Dec.: −84.02 mas/yr
Parallax (π)	30.91±0.15 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	+0.8
Orbit
Period (P)	15,000 d
Eccentricity (e)	Template:Val
Periastron epoch (T)	2415568 JD
Argument of periastron (ω) (primary)	Template:Val°
Semi-amplitude (K1) (primary)	Template:Val km/s
Details
δ And Aa
Mass	~1.3 Template:Solar mass
Radius	Template:Val Template:Solar radius
Luminosity	Template:Val Template:Solar luminosity
Surface gravity (log g)	Template:Val cgs
Temperature	Template:Val K
Metallicity [Fe/H]	0.04 dex
Rotational velocity (v sin i)	6.5 km/s
Age	3.2 Gyr
δ And Ab
Mass	0.6–0.8 Template:Solar mass
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data

Delta Andromedae is a triple star system in the northern constellation of Andromeda. Its identifier is a Bayer designation that is Latinized from δ Andromedae, and abbreviated Delta And or δ And, respectively. The system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 3.28. Based upon parallax measurements, it is located at a distance of approximately Template:Convert from the Sun. The system is drifting closer with a radial velocity of −10 km/s.

In Chinese, (), meaning Legs (asterism), refers to an asterism consisting of δ Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, ι Piscium, ε Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for δ Andromedae itself is (, Template:Langx.) Apart from its Bayer designation, it was also given the title Delta by Elijah H. Burritt in his star atlas.

This is a long-period spectroscopic binary with an orbital period of approximately 15,000 days (41 years). The primary of the spectroscopic binary, component Aa, has a stellar classification of K3 III, indicating that it is an aging giant star. It most likely evolved from a F-type main sequence star after consuming the hydrogen at its core. The secondary, component Ab, is a relatively faint K-type dwarf, which has been imaged using a stellar coronagraph. The pair have a physical separation of Template:Val.

The system has two companions, the closest of which is an orbiting red dwarf of class M3 with a separation of at least 940 astronomical units.

An excess of infrared emission from δ Andromedae suggested that it may be surrounded by a shell of dust. In 2003 it was determined that this is more likely a circumstellar debris disk.

External links

• The Constellation Andromeda: The Chained Maiden Template:Webarchive, web page, European Southern Observatory outreach.
• Image Delta Andromedae