26 Andromedae

26 Andromedae, abbreviated 26 And, is a binary star system^[1] in the constellation Andromeda. 26 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10, 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, which yields a distance of about 600 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.^[9]

26 Andromedae

A visual band light curve for 26 Andromedae, adapted from Zasche and Svoboda (2008)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda
A
Right ascension	00h 18m 42.16888s[2]
Declination	+43° 47′ 28.1082″[2]
Apparent magnitude (V)	6.11[3]
B
Right ascension	00h 18m 41.66160s[4]
Declination	+43° 47′ 24.9776″[4]
Apparent magnitude (V)	9.70[3]
Characteristics
Evolutionary stage	main sequence[5]
Spectral type	B8 V[6] + F3 V[1]
B−V color index	−0.074±0.004[7]
Variable type	suspected[8][1]
Astrometry
A
Radial velocity (Rv)	+3.3[9] km/s
Proper motion (μ)	RA: 23.328[2] mas/yr Dec.: −2.755[2] mas/yr
Parallax (π)	5.3927 ± 0.0192 mas[2]
Distance	605 ± 2 ly (185.4 ± 0.7 pc)
Absolute magnitude (MV)	0.02[10]
B
Proper motion (μ)	RA: 22.083[2] mas/yr Dec.: −3.568[2] mas/yr
Parallax (π)	5.4683 ± 0.0142 mas[4]
Distance	596 ± 2 ly (182.9 ± 0.5 pc)
Absolute magnitude (MV)	4.00[11]
Details
A
Mass	3.54±0.12[5] M☉
Radius	3.76[12] R☉
Luminosity	219[6] L☉
Surface gravity (log g)	3.82[2] cgs
Temperature	11,939[6] K
Rotational velocity (v sin i)	18[5] km/s
Age	95[6] Myr
B
Mass	1.0[4] M☉
Radius	1.2[4] R☉
Luminosity	1.5[4] L☉
Surface gravity (log g)	4.32[4] cgs
Temperature	5,924[4] K
Age	6.1[4] Gyr
Other designations
26 And, BD+42°48, HD 1438, HIP 1501, HR 70, SAO 36256, PPM 42805, WDS J00187+4347[13]
Database references
SIMBAD	data

The magnitude 6.11^[3] primary, component A, is a B-type main-sequence star with a stellar classification of B8 V.^[6] The star has 3.54^[5] times the mass of the Sun and 3.76^[12] times the Sun's radius. It is around 95^[6] million years old and is spinning with a projected rotational velocity of 18 km/s.^[5] 26 And is radiating 219^[6] times the Sun's luminosity from its photosphere at an effective temperature of 11,939 K.^[6] 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.^[12]

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.^[1] This system's X-ray emission hasn't been detected yet, with an upper limit of L_x < 29.79 erg/s.^[3]

References

1. 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.
2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
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. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
5. 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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.
12. 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.
13. "26 And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 25, 2018.

External links

• Image 26 Andromedae