)  | |
| Observation data Epoch 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] |
| U−B color index | +1.48[2] |
| B−V color index | +1.28[2] |
| R−I color index | +0.66[4] |
| Astrometry | |
| Radial velocity (Rv) | −7.3 ± 0.9[5] km/s |
| Proper motion (μ) | RA: +114.45[1] mas/yr Dec.: −84.02[1] mas/yr |
| Parallax (π) | 30.91 ± 0.15[1] mas |
| Distance | 105.5 ± 0.5 ly (32.4 ± 0.2 pc) |
| Absolute magnitude (MV) | +0.8[6] |
| Orbit[7] | |
| Period (P) | 15,000 d |
| Eccentricity (e) | 0.34 ± 0.14 |
| Periastron epoch (T) | 2415568 JD |
| Argument of periastron (ω) (primary) | 356.1 ± 5.2° |
| Semi-amplitude (K1) (primary) | 4.0 ± 2.7 km/s |
| Details | |
| δ And A | |
| Mass | ~1.3[8] M☉ |
| Radius | 13.6 ± 0.3[9] R☉ |
| Luminosity | 68 ± 4[9] L☉ |
| Surface gravity (log g) | 2.0 ± 0.3[3] cgs |
| Temperature | 4,315[10] K |
| Metallicity [Fe/H] | 0.04[10] dex |
| Rotational velocity (v sin i) | 6.5[10] km/s |
| Age | 3.2[11] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Andromedae (δ And, δ Andromedae) is a multiple star system in the northern constellation of Andromeda. Based upon parallax measurements, it is located at a distance of approximately 105.5 light-years (32.3 parsecs) from the Earth.
In Chinese, 奎宿 (Kuí Sù), 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 奎宿五 (Kuí Sù wǔ, English: the Fifth Star of Legs.)[13] Apart from its Bayer designation, it was also given the title Delta by Elijah H. Burritt in his star atlas.[14]
This is a long-period spectroscopic binary with an orbital period of approximately 15,000 days (41 years) and an overall apparent visual magnitude of approximately 3.28. The primary of the spectroscopic binary has a stellar classification of K3 III, indicating that it is a giant star.[5][7] It most likely evolved from a F-type main sequence star after consuming the hydrogen at its core.[11] The secondary is a relatively faint K-type dwarf, which has been imaged using a stellar coronagraph.[15] The star has two optical companions, the closest of which may be an orbiting red dwarf of class M3 with a separation of at least 900 astronomical units.[16]
An excess of infrared emission from δ Andromedae suggested that it may be surrounded by a shell of dust.[3] In 2003 it was determined that this is more likely a circumstellar debris disk.[11]
References
- ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
- ^ a b c Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99). Bibcode:1966CoLPL...4...99J.
- ^ a b c Judge, P. G.; Jordan, C.; Rowan-Robinson, M. (January 1, 1987), "Delta Andromedae (K3 III) - an IRAS source with an unusual ultraviolet spectrum", Monthly Notices of the Royal Astronomical Society, 224: 93–106, Bibcode:1987MNRAS.224...93J, doi:10.1093/mnras/224.1.93.
- ^ Hoffleit, D.; Warren Jr., W. H., "HR 165, database entry", The Bright Star Catalogue (5th (Preliminary Version) ed.), CDS ID V/50. Accessed on line August 28, 2008.
- ^ a b c "del And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved August 28, 2008.
- ^ Ryon, Jenna; et al. (August 2009), "Comparing the Ca ii H and K Emission Lines in Red Giant Stars", Publications of the Astronomical Society of the Pacific, 121 (882): 842, arXiv:0907.3346, Bibcode:2009PASP..121..842R, doi:10.1086/605456, S2CID 17821279.
- ^ a b Bakos, Gustav A. (February 1976), "The spectroscopic orbit of δ Andromedae", Journal of the Royal Astronomical Society of Canada, 70: 23–26, Bibcode:1976JRASC..70...23B.
- ^ Gontcharov, G.A.; Kiyaeva, O. V. (2002), "Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos I. Comparison with known orbits", Astronomy and Astrophysics, 391, 647–657, Bibcode:2002A&A...391..647G, doi:10.1051/0004-6361:20020896.
- ^ a b Piau, L.; et al. (February 2011), "Surface convection and red-giant radius measurements", Astronomy and Astrophysics, 526: A100, arXiv:1010.3649, Bibcode:2011A&A...526A.100P, doi:10.1051/0004-6361/201014442, S2CID 118533297
- ^ a b c Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209
- ^ a b c Decin, G.; et al. (November 2003), "Age Dependence of the Vega Phenomenon: Observations", The Astrophysical Journal, 598 (1): 636–644, arXiv:astro-ph/0308294, Bibcode:2003ApJ...598..636D, doi:10.1086/378800, S2CID 16751327
- ^ "Entry 00393+3052", The Washington Double Star Catalog, United States Naval Observatory, archived from the original on 2008-04-12, retrieved 2008-08-28
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
- ^ Richard Hinckley Allen (1899) Star-names and Their Meanings, p. 38.
- ^ Bottom, M.; et al. (August 4, 2015), "Resolving the Delta Andromedae Spectroscopic Binary with Direct Imaging", The Astrophysical Journal, 809 (1): 11, arXiv:1506.07517, Bibcode:2015ApJ...809...11B, doi:10.1088/0004-637X/809/1/11, S2CID 32786144.
- ^ Kaler, James B., "DELTA AND (Delta Andromedae)", Stars, University of Illinois, retrieved 2012-01-23
External links
- The Constellation Andromeda: The Chained Maiden, web page, European Southern Observatory outreach.
- Entry at heavens-above.com.
- Image Delta Andromedae