Psi Scorpii

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]
Distance162 ± 2 ly
(49.6 ± 0.6 pc)
Absolute magnitude (MV)+1.55[5]
Orbit[6]
Period (P)10 years
Semi-major axis (a)6.4 au
Details[6]
ψ Sco A
Mass1.95 M
Radius2.1 R
Luminosity18.6[7] L
Surface gravity (log g)4.134±0.071[8] cgs
Temperature8,350 K
Rotational velocity (v sin i)42.3±0.6[9] km/s
Age630 Myr
ψ Sco B
Mass0.64 M
Radius0.60 R
Temperature4,200 K
Age630 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
SIMBADdata

Psi Scorpii, which is Latinized from ψ Scorpii, is a binary 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. The system is drifting closer to the Sun with a radial velocity of −5 km/s.[4]

Characteristics

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Data collected during the Hipparcos mission suggested it is an astrometric binary.[11] The companion was directly detected in 2025, with the GRAVITY instrument at VLTI. The astrometric data is consistent with an orbital period of 10 years, suggesting a separation of 3.4 astronomical units.[6]

The primary 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 1.95 the mass and 2.1 times the radius of the Sun,[6] and is shining with 18.6 times the Sun's luminosity.[7] The effective temperature of the star's outer atmosphere is 8,350 K. Psi Scorpii A is around 630 million years old[6] and is spinning with a projected rotational velocity of 42.3 km/s.[12]

The secondary is has around 0.64 times the mass, 0.6 times the radius and a temperature of 4,200 K. It is 6.7 magnitudes fainter than the primary.[6]

References

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  1. ^ a b c d e f 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. ^ a b c d Hoffleit, Dorrit; Jaschek, Carlos (1991), "The Bright star catalogue", New Haven, Conn.: Yale University Observatory, 5th Rev.ed., Bibcode:1991bsc..book.....H.
  3. ^ a b 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. ^ a b 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. ^ a b c d e f Waisberg, Idel; Klein, Ygal; Katz, Boaz (2025-10-07), "Hidden Companions to Intermediate-mass Stars. Upgraded Multiplicity 1 → 2. XXXI. Discovery of a 0.64M , 3.4 au Companion to Psi Scorpii", Research Notes of the AAS, 9 (10): 260, doi:10.3847/2515-5172/ae0e62, ISSN 2515-5172.
  7. ^ a b 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.
  8. ^ Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay; Rojas-Ayala, Bárbara; Fleming, Scott W.; Rose, Mark E.; Tenenbaum, Peter; Ting, Eric B. (2019-10-01), "The Revised TESS Input Catalog and Candidate Target List", The Astronomical Journal, 158 (4): 138, arXiv:1905.10694, Bibcode:2019AJ....158..138S, doi:10.3847/1538-3881/ab3467, ISSN 0004-6256. Psi Scorpii's database entry at VizieR.
  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. ^ 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.
[edit]
  • Kaler, James B. (August 12, 2016), "Chi and Psi Scorpii", Stars, University of Illinois, retrieved 2016-09-25.