Astronomy:Delta Andromedae
Observation data 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−B color index | +1.48[2] |
B−V color index | +1.28[2] |
R−I color index | +0.66[5] |
Astrometry | |
Radial velocity (Rv) | −9.88±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[1] mas |
Distance | 105.5 ± 0.5 ly (32.4 ± 0.2 pc) |
Absolute magnitude (MV) | +0.8[7] |
Orbit[8] | |
Period (P) | 15,000 d |
Eccentricity (e) | 0.34±0.14 |
Periastron epoch (T) | 2415568 JD |
Argument of periapsis (ω) (primary) | 356.1±5.2° |
Semi-amplitude (K1) (primary) | 4.0±2.7 km/s |
Details[4] | |
δ And Aa | |
Mass | ~1.3[9] M☉ |
Radius | 13.6±0.3 R☉ |
Luminosity | 68±4 L☉ |
Surface gravity (log g) | 2.0±0.3[3] cgs |
Temperature | 4,315±9 K |
Metallicity [Fe/H] | 0.04 dex |
Rotational velocity (v sin i) | 6.5[6] km/s |
Age | 3.2 Gyr |
δ And Ab | |
Mass | 0.6–0.8 M☉ |
Other designations | |
Database references | |
SIMBAD | data |
Delta Andromedae, Latinized from δ Andromedae, is a triple star[12] system in the northern constellation of Andromeda. The system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 3.28.[2] Based upon parallax measurements, it is located at a distance of approximately 105.5 light-years (32.3 parsecs) from the Sun.[1] The system is drifting closer with a radial velocity of −10 km/s.[6]
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). The primary of the spectroscopic binary, component Aa, has a stellar classification of K3 III, indicating that it is an aging giant star.[3][8] It most likely evolved from a F-type main sequence star after consuming the hydrogen at its core.[15] 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 11.55±0.13 astronomical unit|AU.[4] The system has two companions, the closest of which is most likely 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][17] In 2003 it was determined that this is more likely a circumstellar debris disk.[15]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode: 1966CoLPL...4...99J.
- ↑ 3.0 3.1 3.2 3.3 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, doi:10.1093/mnras/224.1.93, Bibcode: 1987MNRAS.224...93J.
- ↑ 4.0 4.1 4.2 Bottom, M. et al. (August 4, 2015), "Resolving the Delta Andromedae Spectroscopic Binary with Direct Imaging", The Astrophysical Journal 809 (1): 11, doi:10.1088/0004-637X/809/1/11, Bibcode: 2015ApJ...809...11B.
- ↑ Hoffleit, D.; Warren Jr., W. H., "HR 165, database entry", The Bright Star Catalogue (CDS), http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=165 ID V/50. Accessed on line August 28, 2008.
- ↑ 6.0 6.1 6.2 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, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 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, doi:10.1086/605456, Bibcode: 2009PASP..121..842R.
- ↑ 8.0 8.1 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: 647, doi:10.1051/0004-6361:20020896, Bibcode: 2002A&A...391..647G.
- ↑ "del And". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+And.
- ↑ "Entry 00393+3052", The Washington Double Star Catalog (United States Naval Observatory), http://ad.usno.navy.mil/wds/wdsnewframe1.html, retrieved 2008-08-28
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ (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.
- ↑ 15.0 15.1 Decin, G. et al. (November 2003), "Age Dependence of the Vega Phenomenon: Observations", The Astrophysical Journal 598 (1): 636–644, doi:10.1086/378800, Bibcode: 2003ApJ...598..636D
- ↑ Kaler, James B., "DELTA AND (Delta Andromedae)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/deltaand.html, retrieved 2012-01-23
- ↑ Wirsich, J. (August 1998), "The Chromospheric Radiation on the Circumstellar Shell of δ Andromedae", The Astrophysical Journal 502 (2): 909–917, doi:10.1086/305935, Bibcode: 1998ApJ...502..909W.
External links
- The Constellation Andromeda: The Chained Maiden , web page, European Southern Observatory outreach.
- Image Delta Andromedae
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