Multiple star system in the constellation Andromeda
δ Andromedae Location of δ Andromedae (circled)
Observation dataEpoch J2000.0 Equinox J2000.0 (ICRS ) Constellation Andromeda Right ascension 00h 39m 19.67518s [ 1] Declination +30° 51′ 39.6783″[ 1] Apparent magnitude (V)3.28[ 2] Characteristics Spectral type K3 III[ 3] K4 ± 2 [ 4] U−Bcolor index +1.48[ 2] B−Vcolor index +1.28[ 2] R−Icolor index +0.66[ 5] Astrometry Radial velocity (Rv )± 0.15[ 6] km/s Proper motion (μ)RA: +114.45[ 1] mas /yr Dec.: −84.02[ 1] mas /yr Parallax (π)30.91± 0.15 mas [ 1] Distance 105.5 ± 0.5 ly pc ) Absolute magnitude (MV )+0.8[ 7] Orbit [ 8] Period (P)15,000d Eccentricity (e)± 0.14Periastron epoch (T)2415568JD Argument of periastron (ω)± 5.2Semi-amplitude 1 )± 2.7Details[ 4] δ And Aa Mass ~1.3[ 9] M ☉ Radius ± 0.3R ☉ Luminosity ± 4L ☉ Surface gravity (log g )± 0.3[ 3] cgs Temperature ± 9K Metallicity [Fe/H] 0.04 dex Rotational velocity (v sin i )6.5[ 6] Age 3.2 Gyr δ And Ab Mass 0.6–0.8 M ☉ Other designations δ And, Delta Andromedae, Delta And ,31 Andromedae, 31 And ,NSV 15142BD +30 91FK5 20HD 3627HIP 3092HR 165SAO 54058PPM 65514WDS 00393+3052A[ 10] [ 11] Database references SIMBAD data
Delta Andromedae is atriple star [ 12] constellation ofAndromeda . Its identifier is aBayer designation that isLatinized from δ Andromedae, and abbreviated Delta And or δ And, respectively. The system is visible to thenaked eye as a point of light with a combinedapparent visual magnitude of 3.28.[ 2] parallax measurements, it is located at a distance of approximately 105.5light-years (32.3parsecs ) from theSun .[ 1] radial velocity of −10 km/s.[ 6]
InChinese ,奎宿 Kuí Sù Legs (asterism)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 andψ1 Piscium . Consequently, theChinese name for δ Andromedae itself is奎宿五 Kuí Sù wǔ the Fifth Star of Legs .)[ 13] Bayer designation , it was also given the titleDelta byElijah H. Burritt in hisstar atlas .[ 14]
This is a long-periodspectroscopic binary with an orbital period of approximately 15,000 days (41 years). The primary of the spectroscopic binary, component Aa, has astellar classification of K3 III, indicating that it is an aginggiant star .[ 3] [ 8] main sequence star after consuming the hydrogen at its core.[ 15] coronagraph . The pair have a physical separation of± 0.13 AU [ 4]
The system has two companions, the closest of which is an orbitingred dwarf of class M3 with a separation of at least 940 astronomical units .[ 16] [ 17]
Anexcess of infrared emission from δ Andromedae suggested that it may be surrounded by a shell of dust.[ 3] [ 18] debris disk .[ 15]
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