Upsilon Andromedae
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Andromeda |
υ And A | |
Right ascension | 01h 36m 47.84154s[1] |
Declination | +41° 24′ 19.6514″[1] |
Apparent magnitude (V) | 4.10[2] |
υ And D[a] | |
Right ascension | 01h 36m 50.40476s[3] |
Declination | +41° 23′ 32.1228″[3] |
Characteristics | |
Spectral type | F8V[4] + M4.5V[5] |
Apparent magnitude (B) | 4.63[6] |
U−B color index | 0.06 |
B−V color index | 0.54 |
V−R color index | 0.30[7] |
R−I color index | 0.30[7] |
Details | |
υ And A | |
Gyr | |
υ And D[a] | |
Mass | 0.2[5] M☉ |
01368+4124A, 2MASS J01364784+4124200, Gaia DR2 348020448377061376 | |
Database references | |
SIMBAD | data |
υ And D | |
Data sources: | |
Upsilon Andromedae (υ Andromedae, abbreviated Upsilon And, υ And) is a
As of 2015[update], three
Nomenclature
υ Andromedae (Latinised to Upsilon Andromedae) is the system's Bayer designation. Under the rules for naming objects in binary star systems, the two components are designated A and B.[14] Under the same rules, the first planet discovered orbiting υ Andromedae A should be designated υ Andromedae Ab. Though this more formal form is occasionally used to avoid confusion with a secondary star υ Andromedae B, it is more commonly referred to as υ Andromedae b. The other planets discovered were designated υ Andromedae c, d, and e, in order of their discovery.
In July 2014 the International Astronomical Union (IAU) launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[15] The process involved public nomination and voting for the new names.[16] In December 2015, the IAU announced the winning names were Titawin for υ Andromedae A and Saffar, Samh and Majriti for three of its planets (b, c and d, respectively).[17]
The winning names were those submitted by the Vega Astronomy Club of
In 2016, the IAU organized a
In
Stellar system
Upsilon Andromedae is located fairly close to the
The Catalog of Components of Double and Multiple Stars and Washington Double Star Catalog (WDS) both list two companion stars: magnitude 12.6 UCAC3 263-13722 110" away, listed as component B; and magnitude 10.3 F2 star TYC 2822-2067-1 280" away, listed as component C.[22]
A fainter and closer star, discovered in 2002, is confusingly referred to in the discovery paper as υ Andromedae B even though that designation is also used for a different companion. This 13th-magnitude red dwarf is 55" from υ Andromedae A and is believed to be the only one of the companions physically associated, at the same distance and a projected separation of 750 AU. It has been added to the WDS as component D.[22]
Upsilon Andromedae A
Upsilon Andromedae A is a yellow-white dwarf of
The X-ray emission of Upsilon Andromedae A is low for a star of its spectral class. This means that the star may be moving, or move soon, out of the main sequence and expand its radius to become a red giant star. This is consistent with the upper limits on the age of this star.[25]
Upsilon Andromedae A was ranked 21st in the list of top 100 target stars for NASA's cancelled Terrestrial Planet Finder mission.[26]
The star rotates at an inclination of 58+9
−7 degrees relative to Earth.[12]
Upsilon Andromedae B
The red dwarf companion has a spectral type M4.5V and is located at a
Planetary system
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b (Saffar) | 1.70+0.33 −0.24[28] MJ |
0.0594±0.0003[7] | 4.62±0.23 | 0.022±0.007 | 24±4[28]° | 1.8[29] RJ |
c (Samh) | 13.98+2.3 −5.3[7] MJ |
0.829±0.043[7] | 241.26±0.64 | 0.260±0.079 | 7.9 ± 1[7]° | — |
d (Majriti) | 10.25+0.7 −3.3[7] MJ |
2.530±0.014[7] | 1,276.46±0.57 | 0.299±0.072 | 23.8 ± 1[7]° | — |
e (unconfirmed) | > 1.059[30] MJ | ~5.25[30] | 3,848.86±0.74 | 0.0055±0.0004 | — | — |
The innermost planet of the Upsilon Andromedae system was discovered in 1996 and announced in January 1997, together with the planet of Tau Boötis and the innermost planet of 55 Cancri.[31] The discovery was made by Geoffrey Marcy and R. Paul Butler, both astronomers at San Francisco State University. The planet, designated Upsilon Andromedae b, was discovered by measuring changes in the star's radial velocity induced by the planet's gravity. Because of its closeness to the parent star, it induced a large wobble which was detected relatively easily. The planet appears to be responsible for enhanced activity in the chromosphere of its star.[32]
Even when the first planet was taken into account, there still remained significant residuals in the radial velocity measurements, and it was suggested there might be a second planet in orbit. In 1999, astronomers at both
The orbital parameters of this three-planet system have been fully determined. The system is not
Additional planets
Astronomers initially thought that a fourth planet in this system could not exist because it would have made the planetary system unstable and would have been ejected.[38] But in 2007, an island region of stability was reported where a fourth planet could exist.[39]
The existence of further planets too small or distant to detect has not been ruled out, though the presence of Jupiter-mass planets as close as 5 AU from Upsilon Andromedae A would make the system unstable.[40] However, a potential fourth planet (Upsilon Andromedae e) was discovered in 2010. This planet seems to be in a 3:1 resonance with Upsilon Andromedae d.[30] Subsequent studies in 2011 and 2014, while finding some evidence for a fourth planet, found large inconsistencies in the estimated orbital period of Upsilon Andromedae e depending on what dataset was used,[41] suggesting that the apparent planetary signal is more likely to be an instrumental artifact.[42][43]
If it exists, Upsilon Andromedae e would have a
Upsilon Andromedae does not appear to have a circumstellar dust disk similar to the Kuiper belt in the Solar System.[44] This may be the result of perturbations from the companion star removing material from the outer regions of the Upsilon Andromedae A system.[5]
See also
- 51 Pegasi
- Kepler-56
- List of exoplanets discovered before 2000 - Saffar, Samh and Majriti
- PSR B1257+12
Notes
References
- ^ .
- ^ S2CID 18370219.
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- ^ S2CID 7111977.
- ^ "NLTT 5367 -- High proper-motion Star". SIMBAD Astronomical Object Database. Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-20.
- ^ S2CID 120127162.
- S2CID 51814894.
- ^ Bibcode:1998A&A...336..942F.
- .
- ^ "Exoplanets Data Explorer". exoplanet.org. Retrieved 4 September 2016.
- ^ S2CID 6708869., as "HD 9826".
- ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016.
- ^ Hartkopf, William I.; Mason, Brian D. "Addressing confusion in double star nomenclature: The Washington Multiplicity Catalog". U.S. Naval Observatory. Archived from the original on 2011-05-17. Retrieved 2016-01-19.
- ^ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
- ^ "NameExoWorlds The Process". Archived from the original on 2015-08-15. Retrieved 2015-09-05.
- ^ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
- ^ "NameExoWorlds The Approved Names". Archived from the original on 2018-02-01. Retrieved 2016-01-17.
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日
- ^ a b Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I. "Washington Double Star Catalog". U.S. Naval Observatory. Archived from the original on 2016-03-14. Retrieved 2012-06-25.
- ^ Holmberg; et al. (2007). "Record 970". Geneva-Copenhagen Survey of Solar neighbourhood. Retrieved 19 November 2008.
- ^ S2CID 2241081.
- ^ S2CID 55184357.
- ^ Mullen, Leslie (2 June 2011). "Rage Against the Dying of the Light". Astrobiology Magazine. Archived from the original on 2011-06-04. Retrieved 2011-06-07.
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- ^ S2CID 19960378.
- ISSN 1538-4357.
- ^ .
- doi:10.1086/310444.
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- S2CID 119067572. (web version)
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- S2CID 14800854.
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- S2CID 118409453.
- S2CID 121999545.
External links
- "A Triple-Planet System Orbiting Ups Andromedae". San Francisco State University. Lick Observatory. Archived from the original on 2012-04-24. Retrieved 2008-06-23.
- "Mystery Solved: How The Orbits Of Extrasolar Planets Became So Eccentric". SpaceDaily. 2005-04-14. Retrieved 2008-06-23.
- "Upsilon Andromedae". The Internet Encyclopedia of Science. Retrieved 2008-06-23.
- "Upsilon Andromedae". The Planet Project. Archived from the original on 2008-05-18. Retrieved 2008-06-23.
- "Upsilon Andromedae 2". SolStation. Retrieved 2008-06-23.
- "The Upsilon Andromedae Planetary System". Harvard-Smithsonian Center for Astrophysics. Retrieved 2008-06-23.
- "υ Andromedae". AlcyoneEphemeris. Archived from the original on 2018-09-29. Retrieved 2008-06-23.
- HR 0458
- CCDM 01367+4125