106 Aquarii

This article is about i¹ Aquarii. For other star systems with this Bayer designation, see i Aquarii.

106 Aquarii, abbreviated 106 Aqr, is a single^[11] star in the equatorial constellation of Aquarius. 106 Aquarii is the Flamsteed designation, and it also bears the Bayer designation i¹ Aquarii. It has an apparent visual magnitude of +5.2,^[3] making it bright enough to be viewed from the suburbs according to the Bortle Dark-Sky Scale. An annual parallax shift of 8.61^[6] milliarcseconds yields an estimated distance of around 380 light-years (120 parsecs) from Earth.

106 Aquarii

Location of 106 Aquarii (circled)[1]
Observation data Epoch J2000.0 (ICRS)      Equinox J2000.0 (ICRS)
Constellation	Aquarius
Right ascension	23h 44m 12.07852s[2]
Declination	–18° 16′ 36.9999″[2]
Apparent magnitude (V)	+5.244[3]
Characteristics
Spectral type	B9 V[4]
U−B color index	–0.239[3]
B−V color index	–0.086[3]
Astrometry
Radial velocity (Rv)	+14.0[5] km/s
Proper motion (μ)	RA: +27.23[6] mas/yr Dec.: –2.94[6] mas/yr
Parallax (π)	8.7588 ± 0.2859 mas[2]
Distance	370 ± 10 ly (114 ± 4 pc)
Absolute magnitude (MV)	−0.07[7]
Details
Mass	3.0[8] M☉
Radius	2.7–3.2[9] R☉
Luminosity	151.88[7] L☉
Surface gravity (log g)	3.791±0.011[8] cgs
Temperature	11,555±50[8] K
Rotational velocity (v sin i)	328±48[8] km/s
Other designations
i1 Aqr, BD−19°6500, FK5 1621, HD 222847, HIP 117089, HR 8998, SAO 165854[10]
Database references
SIMBAD	data

The spectrum of this star fits a stellar classification of B9 V,^[4] indicating this is a B-type main sequence star. It is spinning rapidly with a projected rotational velocity of 328 km/s.^[8] The star has 3^[8] times the mass of the Sun and is radiating 152^[7] times the Sun's luminosity from its photosphere at an effective temperature of 11,555 K.^[8] X-ray emission with a luminosity of 6.0×10²⁹ erg s⁻¹ has been detected from this star. This is unusual since a B-type star normally does not have any significant X-ray emission. Instead, it may have an undetected lower mass companion.^[12]

References

1. Of the grouping of four stars within the circle, 106 Aquarii is the second from the left per:
   Sinnott, Roger W.; et al. (1997), Millennium Star Atlas, vol. 3, Sky Publishing Corporation and the European Space Agency, p. 1351, ISBN 0-933346-82-4.
2. 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.
3. Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
4. Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
5. Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
6. van Leeuwen, F. (November 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, S2CID 18759600.
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. Huang, Wenjin; et al. (2010), "A Stellar Rotation Census of B Stars: From Zams to Tams", The Astrophysical Journal, 722 (1): 605–619, arXiv:1008.1761, Bibcode:2010ApJ...722..605H, doi:10.1088/0004-637X/722/1/605, S2CID 118532653.
9. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
10. "106 Aqr -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-15.
11. Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925–1929, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x, S2CID 119120749.
12. Hubrig, S.; et al. (June 2001), "Search for low-mass PMS companions around X-ray selected late B stars", Astronomy and Astrophysics, 372: 152–164, arXiv:astro-ph/0103201, Bibcode:2001A&A...372..152H, doi:10.1051/0004-6361:20010452, S2CID 17507782.

External links

• Aladin previewer, image
• Aladin sky atlas, image