6 Andromedae

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6 Andromedae
Pegasus constellation map.svg
Red circle.svg
Location of 6 Andromedae (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Andromeda [1]
Right ascension 23h 10m 27.241s [2]
Declination +43° 32 38.53 [2]
Apparent magnitude  (V)5.91 [1]
Characteristics
Spectral type F5 V [3]
U−B color index −0.05 [3]
B−V color index +0.450±0.004 [1]
Astrometry
Radial velocity (Rv)−32.4±0.7 [1] km/s
Proper motion (μ)RA: −211.689 mas/yr [2]
Dec.: −144.535 mas/yr [2]
Parallax (π)35.5518±0.3115  mas [2]
Distance 91.7 ± 0.8  ly
(28.1 ± 0.2  pc)
Absolute magnitude  (MV)3.71 [1]
Orbit [3]
Period (P)3,373±6 d
Periastron epoch (T)53116 ± 16 MJD
Argument of periastron (ω)
(secondary)
165.2±2.0°
Semi-amplitude (K1)
(primary)
8.75±0.09 km/s
Details
Mass 1.30 [4]   M
Radius 1.50+0.03
−0.06
[5]   R
Luminosity 3.090+0.018
−0.017
[5]   L
Surface gravity (log g)4.09±0.14 [4]   cgs
Temperature 6,425±218 [4]   K
Metallicity [Fe/H]−0.19±0.03 [1]   dex
Rotational velocity (v sin i)18 [6]  km/s
Age 2.91 [4]   Gyr
Other designations
6 And, BD+42°4592, FK5 3857, HD 218804, HIP 114430, HR 8825, SAO 52761, PPM 63896 [7]
Database references
SIMBAD data

6 Andromedae is an astrometric binary star [8] system in the northern constellation of Andromeda. [1] The designation comes from the star catalogue of John Flamsteed, first published in 1712. Its apparent visual magnitude is 5.91, [1] which is just bright enough to be visible to the naked eye under good seeing conditions. Based upon an annual parallax shift of 35.6  mas as seen from Earth, [5] it is 92  light years from the Sun. It is moving closer to the Sun with a radial velocity of −32.4 km/s. [1] The system has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.272  arc seconds per annum. [9]

This is a single-lined spectroscopic binary with an orbital period of 9.2 years and an eccentricity of 0.3. [3] Some early observations of the star gave it a subgiant luminosity class and it was published in the Bright Star Catalogue as spectral class F5 IV. More modern measurements identify the visible component as an F-type main-sequence star with a stellar classification of F5 V. [3] [10] The star is an estimated 2.9 [4]  billion years old with 1.3 [4] times the mass of the Sun and 1.5 [5] times the Sun's radius. It is radiating 3.1 [5] times the Sun's luminosity from its photosphere at an effective temperature of around 6,425 K. [4] 6 Andromedae displays an infrared excess at a wavelength of 22 μm, which may indicate a circumstellar disk of warm dusty debris. [6]

The mass of the secondary component is roughly at or above that of the Sun. If it were a single, ordinary star, it should be readily visible as it would be just one magnitude fainter than the primary. The lack of conspicuous ultraviolet emission appears to rule out a white dwarf companion, so it may instead itself be a binary system consisting of two smaller stars having an orbital period between a week and a year. [3]

References

  1. 1 2 3 4 5 6 7 8 9 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  2. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. 1 2 3 4 5 6 Griffin, R. F. (April 2012), "Spectroscopic binary orbits from photoelectric radial velocities - Paper 223: HR 396, HR 7477, HR 7636, and 6 Andromedae", The Observatory, 132 (2): 76−97, Bibcode:2012Obs...132...76G.
  4. 1 2 3 4 5 6 7 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv: 1501.03154 , Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID   33401607.
  5. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  6. 1 2 Mizusawa, Trisha F.; et al. (November 2012), "Exploring the Effects of Stellar Rotation and Wind Clearing: Debris Disks around F Stars", The Astronomical Journal, 144 (5): 16, arXiv: 1208.6248 , Bibcode:2012AJ....144..135M, doi:10.1088/0004-6256/144/5/135, S2CID   41406330, 135.
  7. "6 And". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-02-01.
  8. Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv: astro-ph/0612449 , Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526, S2CID   14010423.
  9. Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv: astro-ph/0412070 , Bibcode:2005AJ....129.1483L, doi:10.1086/427854, S2CID   2603568.
  10. Skiff, B. A. (2014), "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)", VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014), 1, Bibcode:2014yCat....1.2023S.