47 Andromedae

47 Andromedae is a binary star[2] system in the northern constellation of Andromeda. The designation is from the star catalogue of John Flamsteed, first published in 1712. The system has a combined apparent visual magnitude of 5.60,[2] which is just bright enough to be faintly visible to the naked eye under good seeing conditions. The distance to this system, as determined from an annual parallax shift of 15.9805 mas,[1] is about 204 light years. It is moving away from the Sun with a heliocentric radial velocity of +13.3 km/s.[5]

47 Andromedae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Andromeda
Right ascension	01^h 23^m 40.6168^s[1]
Declination	+37° 42′ 53.8084″[1]
Apparent magnitude (V)	5.60 (6.33 + 6.38)[2]
Characteristics
Spectral type	A1m[3] (kA1hF1mF2)[4]
B−V color index	0.276[2]
Astrometry
Radial velocity (Rv)	+13.3±0.9[5] km/s
Proper motion (μ)	RA: 81.773±0.225[1] mas/yr Dec.: −19.592±0.226[1] mas/yr
Parallax (π)	15.9805 ± 0.1578[1] mas
Distance	204 ± 2 ly (62.6 ± 0.6 pc)
Absolute magnitude (MV)	2.30±0.06/2.35±0.06[2]
Orbit[2]
Period (P)	35.36815±0.00015 d
Eccentricity (e)	0.64781±0.00090
Inclination (i)	38°
Periastron epoch (T)	2,454,293.2187 ± 0.0056 HJD
Semi-amplitude (K1) (primary)	39.216±0.079 km/s
Semi-amplitude (K2) (secondary)	40.47±0.073 km/s
Details
47 And A
Mass	1.65[2] M☉
Radius	1.9±0.1[2] R☉
Luminosity	9.0±0.5[2] L☉
Rotational velocity (v sin i)	15±2[2] km/s
Age	710[6] Myr
47 And B
Radius	1.8±0.1[2] R☉
Luminosity	8.6±0.5[2] L☉
Rotational velocity (v sin i)	15±2[2] km/s
Other designations
47 And, BD+36°237, FK5 2093, HD 8374, HIP 6514, HR 395, SAO 54655[7]
Database references
SIMBAD	data

The binary nature of this system was discovered by John Stanley Plaskett and Reynold Kenneth Young in 1919 using radial velocity measurements taken from Photographic plates obtained at Dominion Astrophysical Observatory in Saanich, British Columbia, Canada.[8] It is a double-lined spectroscopic binary with an orbital period of 35.4 days and an eccentricity of 0.65. The components appear to be nearly identical Am stars, with a magnitude difference of 0.05.[2] The combined stellar classification is A1m.[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. Gaia DR2 record for this source at VizieR.
2. Fekel, Francis C.; et al. (September 2011), "New Precision Orbits of Bright Double-lined Spectroscopic Binaries. VII. 47 Andromedae, 38 Cassiopeiae, and HR 8467", The Astronomical Journal, 142 (3): 13, Bibcode:2011AJ....142...69F, doi:10.1088/0004-6256/142/3/69, 69
3. Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
4. Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
5. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
6. De Rosa, R. J.; et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932, S2CID 88503488.
7. "47 And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-22.
8. Plaskett, J. S.; Young, R. K. (February 1919). "Notes from the Dominion Astrophysical Observatory, Victoria, B.C.. Second list of spectroscopic binaries". Journal of the Royal Astronomical Society of Canada. 13: 59–64. Bibcode:1919JRASC..13...59P.