Psi Scorpii

Psi Scorpii, which is Latinized from ψ Scorpii, is a star in the zodiac constellation of Scorpius. It is white in hue and has an apparent visual magnitude of 4.94,^[2] which is bright enough to be faintly visible to the naked eye. Based upon parallax measurements,^[1] it is located at a distance of around 162 light years from the Sun. Data collected during the Hipparcos mission suggests it is an astrometric binary, although nothing is known about the companion.^[11][12] The system is drifting closer to the Sun with a radial velocity of −5 km/s.^[4]

ψ Scorpii

Observation data Epoch J2000      Equinox J2000
Constellation	Scorpius
Right ascension	16h 12m 00.01043s[1]
Declination	−10° 03′ 50.8353″[1]
Apparent magnitude (V)	4.94[2]
Characteristics
Spectral type	A1 V[3]
U−B color index	+0.11[2]
B−V color index	+0.09[2]
Astrometry
Radial velocity (Rv)	−5.10[4] km/s
Proper motion (μ)	RA: −18.000[1] mas/yr Dec.: −36.188[1] mas/yr
Parallax (π)	20.1801 ± 0.2617 mas[1]
Distance	162 ± 2 ly (49.6 ± 0.6 pc)
Absolute magnitude (MV)	+1.55[5]
Details
Mass	2.0[6] M☉
Radius	2.2[7] R☉
Luminosity	18.6[8] L☉
Surface gravity (log g)	4.00[6] cgs
Temperature	8,846±301[6] K
Rotational velocity (v sin i)	42.3±0.6[9] km/s
Age	451[6] Myr
Other designations
ψ Sco, 15 Scorpii, BD−09°4324, FK5 3280, GC 21780, HD 145570, HIP 79375, HR 6031, SAO 141022[10]
Database references
SIMBAD	data

The visible component is an A-type main sequence star with a stellar classification of A1 V;^[3] a class of star that is still fusing hydrogen at its core. It has around twice^[6] the mass and 2.2^[7] times the radius of the Sun, and is shining with 18.6 times the Sun's luminosity.^[8] The effective temperature of the star's outer atmosphere is 8,846 K. Psi Scorpii is around 451 million years old and is spinning with a projected rotational velocity of 42.3 km/s.^[6]

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. Hoffleit, Dorrit; Jaschek, Carlos (1991), "The Bright star catalogue", New Haven, Conn.: Yale University Observatory, 5th Rev.ed., Bibcode:1991bsc..book.....H.
3. Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
4. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 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.
5. 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.
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, S2CID 33401607.
7. Pasinetti Fracassini, L. E.; et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy & Astrophysics, 367 (2): 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
8. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
9. Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv:1012.4858, Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386, S2CID 119286673.
10. "psi Sco -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-09-24.
11. Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv:astro-ph/0612449, Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526, S2CID 14010423.
12. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.

External links

• Kaler, James B. (August 12, 2016), "Chi and Psi Scorpii", Stars, University of Illinois, retrieved 2016-09-25.