96 Aquarii

96 Aquarii is a multiple star[3] system in the zodiac constellation of Aquarius. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It is faintly visible to the naked eye with an apparent visual magnitude of 5.56.[2] The estimated distance to this system, based upon an annual parallax shift of 29.27 mas, is around 111 light years.[1] The system has a relatively large proper motion[3] and it is moving closer to the Sun with a radial velocity of −7 km/s.[5]

96 Aquarii

Observation data Epoch J2000      Equinox J2000
Constellation	Aquarius
Right ascension	23^h 19^m 23.97754^s[1]
Declination	−05° 07′ 27.6485″[1]
Apparent magnitude (V)	5.56[2] + 10.92[3]
Characteristics
Spectral type	F4 V Fe−0.4[4] + M3 V[3]
B−V color index	0.40/1.37[3]
Astrometry
Radial velocity (Rv)	−7.17±0.35[5] km/s
Proper motion (μ)	RA: +201.39[1] mas/yr Dec.: −18.13[1] mas/yr
Parallax (π)	29.27 ± 0.67[1] mas
Distance	111 ± 3 ly (34.2 ± 0.8 pc)
Absolute magnitude (MV)	2.89[2]
Orbit[3]
Primary	Aab
Period (P)	21.2371±0.0020 d
Eccentricity (e)	0.60
Periastron epoch (T)	22478.56 ± 0.38 JHD
Argument of periastron (ω) (secondary)	314±7°
Semi-amplitude (K1) (primary)	42.7±3.6 km/s
Orbit[3]
Companion	Bab
Period (P)	659.9±3.6 d
Eccentricity (e)	0.60
Periastron epoch (T)	51429.1 ± 7.2 JHD
Argument of periastron (ω) (secondary)	59.3±10.6°
Semi-amplitude (K1) (primary)	8.49±1.05 km/s
Details[6]
96 Aqr Aa
Mass	1.32 M☉
Luminosity	5.82[2] L☉
Surface gravity (log g)	4.21±0.14 cgs
Temperature	6,813±232 K
Metallicity [Fe/H]	−0.12±0.08[2] dex
Age	949 Myr
96 Aqr Ba
Mass	0.40 M☉
Other designations
96 Aqr, BD−05° 5966, HD 219877, HIP 115142, HR 8868, SAO 146639[7]
Database references
SIMBAD	data

The visible components, A and B, have an angular separation of 9.8 arc seconds and share a common proper motion. Their presumed orbital period is estimated as 4,400 years. Component A was first identified as a single-lined spectroscopic binary by Adams et al. (1924) at the Mount Wilson Observatory. It has an orbital period of 21.2 days with an eccentricity of 0.60.[3] The Aab pair have an angular separation of 6 mas and a combined stellar classification of F4 V Fe−0.4,[4] matching an F-type main-sequence star with a mild underabundance of iron. Magnitude 10.92 component B is likewise a single-lined spectroscopic binary, having an orbital period of 659.9 days and an eccentricity of 0.70. The separation of Bab is 45 mas,[3] and their spectrum matches a red dwarf class of M3 V.[3]

References

1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
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.
3. Tokovinin, A. A.; Gorynya, N. A. (April 2007), "New spectroscopic components in multiple systems. V", Astronomy and Astrophysics, 465 (1): 257−261, Bibcode:2007A&A...465..257T, doi:10.1051/0004-6361:20066888.
4. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
5. Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213.
6. 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.
7. "96 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-05.