Astronomy:AH Scorpii
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 11m 17.01945s[1] |
| Declination | −32° 19′ 30.7140″[1] |
| Characteristics | |
| Evolutionary stage | OH/IR RSG[2] |
| Spectral type | M4-5 Ia-Iab[3] |
| B−V color index | +2.57[4] |
| Variable type | SRc[3] |
| Astrometry | |
| Radial velocity (Rv) | −13.40±2.4[5] km/s |
| Proper motion (μ) | RA: −2.322±0.115[1] mas/yr Dec.: −2.610±0.068[1] mas/yr |
| Parallax (π) | 0.5632 ± 0.0799[1] mas |
| Distance | 7,400±620 ly (2,260±190[6] pc) |
| Absolute magnitude (MV) | −5.8[7] |
| Details | |
| Mass | 20[8] M☉ |
| Radius | 1,411±124[4] R☉ |
| Luminosity | 329,000±86,000[4] L☉ |
| Surface gravity (log g) | −0.5[4] cgs |
| Temperature | 3,682[4] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
AH Scorpii (abbreviated to AH Sco) is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.
Observational history
In 1907, Henrietta Swan Leavitt and Edward Charles Pickering announced the discovery of this variable star.[10] It was given its variable star designation, AH Scorpii, in 1912.[11] The total visual magnitude range is 6.5 - 9.6.[12]
Distance
Prior to the 21st century, the distance of AH Scorpii was considered to be uncertain, between about 1.5 and 4.6 kpc. VLBI measurements of the masers have provided an accurate distance of 2,260 parsecs based on observation of SiO, H2O, and OH masers in its oxygen-rich circumstellar material. 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.[6] Gaia Data Release 3 includes a parallax of 0.5632±0.0799 mas, corresponding to a distance of about 1.9 kpc.[1]
Characteristics
The star is a dust-enshrouded red supergiant[13] and is classified as a semiregular variable star with a main period of 714 days.[12] No long secondary periods have been detected.[14]
Modelling of AH Scorpii near maximum light has determined an effective temperature of 3,682±190 K and a luminosity of 330,000±86,000 L☉. A radius of 1,411±124 R☉ was determined from an angular diameter of 5.81±0.15 mas and the given distance of 2.26±0.19 kpc.[4] Its angular diameter was re-measured at 5.05±0.5 mas in 2023.[15]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Bowers, P. F. (December 1981). "Supergiant OH/IR stars.". The Astronomical Journal 86: 1930–1934. doi:10.1086/113074. ISSN 0004-6256. Bibcode: 1981AJ.....86.1930B.
- ↑ 3.0 3.1 Samus, N. N. et al. (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.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 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. doi:10.1051/0004-6361/201220920. Bibcode: 2013A&A...554A..76A.
- ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 Chen, Xi; Shen, Zhi-Qiang (2008). "VLBI Observations of SiO Masers around AH Scorpii". The Astrophysical Journal 681 (2): 1574–1583. doi:10.1086/588186. Bibcode: 2008ApJ...681.1574C.
- ↑ 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.
- ↑ González-Torà, G.; Wittkowski, M.; Davies, B.; Plez, B. (2024-03-01). "The effect of winds on atmospheric layers of red supergiants II. Modelling VLTI/GRAVITY and MATISSE observations of AH Sco, KW Sgr, V602 Car, CK Car, and V460 Car". Astronomy and Astrophysics 683: A19. doi:10.1051/0004-6361/202348047. ISSN 0004-6361. Bibcode: 2024A&A...683A..19G.
- ↑ "Download Data". AAVSO. https://www.aavso.org/data-download.
- ↑ Leavitt, Henrietta S.; Pickering, Edward C. (December 1907). "25 New Variable Stars in Harvard Map, Nos. 24, 36, and 42". Harvard College Observatory Circular 135: 1-3. Bibcode: 1907HarCi.135....1L. https://articles.adsabs.harvard.edu/pdf/1907HarCi.135....1L. Retrieved 18 September 2025.
- ↑ Duner; Hartwig; Muller (June 1912). "Benennung von neu entdeckten veränderlichen Sternen". Benennung von neu entdeckten veränderlichen Sternen 191 (19): 341-358. doi:10.1002/asna.19121911902. Bibcode: 1912AN....191..341.. https://articles.adsabs.harvard.edu/pdf/1912AN....191..341.. Retrieved 18 September 2025.
- ↑ 12.0 12.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedkiss - ↑ 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 (1): 273–289. doi:10.1051/0004-6361:20042555. Bibcode: 2005A&A...438..273V.
- ↑ Percy, John R.; Sato, Hiromitsu (2009). "Long Secondary Periods in Pulsating Red Supergiant Stars". Journal of the Royal Astronomical Society of Canada 103 (1): 11. Bibcode: 2009JRASC.103...11P.
- ↑ González-Torà, G.; Wittkowski, M.; Davies, B.; Plez, B. (December 19, 2023). "The effect of winds on atmospheric layers of red supergiants II. Modelling VLTI/GRAVITY and MATISSE observations of AH Sco, KW Sgr, V602 Car, CK Car and V460 Car". Astronomy & Astrophysics 683: A19. doi:10.1051/0004-6361/202348047. ISSN 0004-6361. Bibcode: 2024A&A...683A..19G.
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