AH Scorpii

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AH Scorpii
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 17h 11m 17.02114s[1]
Declination −32° 19′ 30.7132″[1]
Apparent magnitude (V) 6.5 - 9.6[2]
Spectral type M4-5 Ia-Iab[3]
B−V color index +2.57[4]
Variable type SRc[3]
Radial velocity (Rv)−13.40 ± 2.4[5] km/s
Proper motion (μ) RA: −4.999±0.433[6] mas/yr
Dec.: −2.041±0.282[6] mas/yr
Parallax (π)1.7338 ± 0.2216[6] mas
Distance7,400±620 ly
(2,260±190[7] pc)
Absolute magnitude (MV)−5.8[8]
Radius1,411 ± 124[4] R
Diameter1,411 ± 124[4] D
[4] L
Temperature3,682 ± 190[4] K
Other designations
AH Scorpii, AN 223.1907, GSC 07365-00527, HD 155161, HIP 84071, CD−32°12429, 2MASS J17111702-3219308, IRC−30282, IRAS 17080-3215, RAFGL 1927, AAVSO 1704-32
Database references

AH Scorpii is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known at 1,411 R.

AH Sco is a semiregular variable star with a main period of 714 days. The total visual magnitude range is 6.5 - 9.6.[2] No long secondary periods have been detected.[9]

AH Sco is a dust-enshrouded red supergiant[10] with SiO, H2O, and OH masers in its oxygen-rich circumstellar material. VLBI measurements of the masers have provided an accurate distance of 2,260 parsecs. The masers were observed to be approaching the star at 13 km/s, indicating overall contraction at around phase 0.55 of the visual variations.[7]

Modelling of AH Sco near maximum light has determined an effective temperature of 3,682 K and a luminosity of 330,000 L. A radius of 1,411 D was determined from an angular diameter of 5.81±0.15 mas and the given distance of 2.26±0.19 kpc.[4]

See also


  1. 1.0 1.1 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653. arXiv:0708.1752. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. 2.0 2.1 Kiss, L. L.; Szabó, Gy. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society 372 (4): 1721. arXiv:astro-ph/0608438. Bibcode 2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x.
  3. 3.0 3.1 Samus, N. N.Expression error: Unrecognized word "etal". (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S 1. Bibcode 2009yCat....102025S.
  4. 4.0 4.1 4.2 4.3 4.4 Arroyo-Torres, B.; Wittkowski, M.; Marcaide, J. M.; Hauschildt, P. H. (2013). "The atmospheric structure and fundamental parameters of the red supergiants AH Scorpii, UY Scuti, and KW Sagittarii". Astronomy & Astrophysics 554: A76. arXiv:1305.6179. Bibcode 2013A&A...554A..76A. doi:10.1051/0004-6361/201220920.
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759. arXiv:1606.08053. Bibcode 2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. 6.0 6.1 6.2 Brown, A. G. A. (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.
  7. 7.0 7.1 Chen, Xi; Shen, Zhi-Qiang (2008). "VLBI Observations of SiO Masers around AH Scorpii". The Astrophysical Journal 681 (2): 1574–1583. arXiv:0803.1690. Bibcode 2008ApJ...681.1574C. doi:10.1086/588186.
  8. Baudry, A.; Le Squeren, A. M.; Lepine, J. R. D. (1977). "The supergiant OH stars S Per and AH SCO - Conditions for OH emission in circumstellar envelopes". Astronomy and Astrophysics 54: 593. Bibcode 1977A&A....54..593B.
  9. Percy, John R.; Sato, Hiromitsu (2009). "Long Secondary Periods in Pulsating Red Supergiant Stars". Journal of the Royal Astronomical Society of Canada 103: 11. Bibcode 2009JRASC.103...11P.
  10. Van Loon, J. Th.; Cioni, M.-R. L.; Zijlstra, A. A.; Loup, C. (2005). "An empirical formula for the mass-loss rates of dust-enshrouded red supergiants and oxygen-rich Asymptotic Giant Branch stars". Astronomy and Astrophysics 438: 273. arXiv:astro-ph/0504379. Bibcode 2005A&A...438..273V. doi:10.1051/0004-6361:20042555.