26 Andromedae

26 Andromedae, abbreviated 26 And, is an astrometric binary[6] star system in the constellation Andromeda. 26 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10,[2] which is near the lower limit of visibility to the naked eye. The distance to this system can be estimated from its annual parallax shift of 5.35 mas,[1] which yields a range of 610 light years. At that distance, the visual magnitude of the stars is diminished from an extinction of 0.04 due to interstellar dust.[3] The system is moving further from the Earth with a heliocentric radial velocity of +3.3 km/s.[8]

26 Andromedae
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 18m 42.168563s[1]
Declination +43° 47′ 28.1054″[1]
Apparent magnitude (V) 6.10[2] 6.11 + 9.70[3]
Characteristics
Evolutionary stage main sequence[4]
Spectral type B8 V[5] + F3 V[6]
B−V color index −0.074±0.004[2]
Variable type suspected[7][6]
Astrometry
Primary
Radial velocity (Rv)+3.3[8] km/s
Proper motion (μ) RA: 23.564[1] mas/yr
Dec.: −2.569[1] mas/yr
Parallax (π)5.3455 ± 0.0689[1] mas
Distance610 ± 8 ly
(187 ± 2 pc)
Absolute magnitude (MV)0.02[9]
Secondary
Absolute magnitude (MV)4.00[10]
Details
Primary
Mass3.54±0.12[4] M☉
Radius3.76[11] R☉
Luminosity219[5] L☉
Temperature11,939[5] K
Rotational velocity (v sin i)18[4] km/s
Age95[5] Myr
Secondary
Luminosity2.09[10] L☉
Temperature6,918[10] K
Other designations
26 And, BD+42° 48, HD 1438, HIP 1501, HR 70, SAO 36256, WDS J00187+4347A[12]
Database references
SIMBADdata

The magnitude 6.11[3] primary, component A, is a B-type main-sequence star with a stellar classification of B8 V.[5] The star has 3.54[4] times the mass of the Sun and 3.76[11] times the Sun's radius. It is around 95[5] million years old and is spinning with a projected rotational velocity of 18 km/s.[4] 26 And is radiating 219[5] times the Sun's luminosity from its photosphere at an effective temperature of 11,939 K.[5] It displays an infrared excess that suggests a circumstellar debris disk orbiting at a distance of 169.3 AU from the star with a temperature of 75 K.[11]

The fainter secondary, component B, is a magnitude 9.70[3] star located 6.2″ from the primary. It is an F-type main-sequence star with a class of F3 V that shows an unexplained long term variability. One of the components of this system displays a slight photometric variation with a period of 3.16 days. This may be caused by pulsation or an ellipsoidal variation.[6] This system's X-ray emission hasn't been detected yet, with an upper limit of Lx < 29.79 erg/s.[3]

References
  1. 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.
  2. 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.
  3. Huélamo, N.; et al. (July 2000), "X-ray emission from Lindroos binary systems", Astronomy and Astrophysics, 359: 227–241, arXiv:astro-ph/0005348, Bibcode:2000A&A...359..227H.
  4. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  5. Wyatt, M. C.; et al. (July 2007), "Steady State Evolution of Debris Disks around A Stars", The Astrophysical Journal, 663 (1): 365–382, arXiv:astro-ph/0703608, Bibcode:2007ApJ...663..365W, doi:10.1086/518404, S2CID 18883195.
  6. Zasche, P.; Svoboda, P. (May 2008), "The Unconfirmed Eclipsing Nature of V348 And and Detection of Variability of HD 1438", Information Bulletin on Variable Stars, 5827: 1, Bibcode:2008IBVS.5827....1Z.
  7. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  8. Steenbrugge, K. C.; et al. (May 2003), "Radial velocities of early-type stars in the Perseus OB2 association", Astronomy and Astrophysics, 402 (2): 587–605, arXiv:astro-ph/0302428, Bibcode:2003A&A...402..587S, doi:10.1051/0004-6361:20030277, S2CID 15771155.
  9. Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
  10. Lindroos, K. P. (May 1985), "A study of visual double stars with early type primaries. IV. Astrophysical data", Astronomy and Astrophysics, 60: 183–221, Bibcode:1985A&AS...60..183L.
  11. Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series, 225 (1): 24, arXiv:1606.01134, Bibcode:2016ApJS..225...15C, doi:10.3847/0067-0049/225/1/15, S2CID 118438871, 15.
  12. "26 And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 25, 2018.
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