AH Scorpii

Last updated
AH Scorpii
Observation data
Epoch J2000       Equinox J2000
Constellation Scorpius
Right ascension 17h 11m 17.01945s [1]
Declination −32° 19 30.7140 [1]
Apparent magnitude  (V)6.5 - 9.6 [2]
Characteristics
Evolutionary stage Red supergiant
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  mas [1]
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
AH  Sco, 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
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.

Contents

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

A visual band light curve for AH Scorpii, plotted from AAVSO data AHScoLightCurve.png
A visual band light curve for AH Scorpii, plotted from AAVSO data

AH Scorpii is a dust-enshrouded red supergiant [10] and is classified as 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. [11] 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. [12]

See also

Notes

    Related Research Articles

    Xi Scorpii is part of a quintuple star system in the constellation Scorpius. It was assigned this designation by Bayer, although Ptolemy had catalogued the star in Libra. Flamsteed assigned it the designation 51 Librae, but this has fallen out of use since modern constellation boundaries assign the star to Scorpius.

    KW Sagittarii is a red supergiant star, located approximately 2,420 parsecs away from the Sun in the direction of the constellation Sagittarius. It is one of the largest known stars, with a diameter about 1,000 times larger than the Sun. If placed at the center of the Solar System, the star's surface would engulf Mars, coming close to Jupiter's orbit.

    V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 13,000 light-years away from the Sun. It has an estimated radius of 1,139 solar radii. If it were placed in the center of the Solar System, it would extend to between the orbits of Mars and Jupiter.

    <span class="mw-page-title-main">NO Aurigae</span> Star in the constellation Auriga

    NO Aurigae is a pulsating variable star in the constellation Auriga. It is an unusually-luminous asymptotic giant branch star about 3,500 light years away. It is a 6th magnitude star faintly visible to the naked eye under very good observing conditions.

    Zeta<sup>1</sup> Scorpii Star in the constellation Scorpius.

    Zeta1 Scorpii is a B-type hypergiant star in the constellation of Scorpius. It has an apparent visual magnitude which varies between 4.66 and 4.86. It is a member of the Scorpius OB1 association, and potentially of the open star cluster NGC 6231, also known as the "Northern jewel box" cluster. Around 36 times as massive as the Sun, it is also one of the most luminous stars known in the Galaxy, with an estimated bolometric luminosity of around 850,000 times that of the Sun and a radius 103 times that of the Sun.

    Zeta<sup>2</sup> Scorpii Star in the constellation Scorpius.

    Zeta2 Scorpii is a K-type orange giant star in the constellation of Scorpius. It has an apparent visual magnitude which varies between 3.59 and 3.65, and is located near the blue-white supergiant star ζ1 Scorpii in Earth's sky. In astronomical terms, ζ2 is much closer to the Sun and unrelated to ζ1 except for line-of sight co-incidence. ζ1 is about 6,000 light-years away and probably an outlying member of open star cluster NGC 6231, whereas ζ2 is a mere 135 light-years distant and thus much less luminous in real terms. ζ2 can also be distinguished from its optical partner, ζ1, because of its orangish colour especially in long-exposure astrophotographs.

    <span class="mw-page-title-main">V4381 Sagittarii</span> Star in the constellation Sagittarius

    V4381 Sagittarii is a variable star in the constellation Sagittarius. A white supergiant of spectral type A2/A3Iab, it is an Alpha Cygni variable that varies between apparent photographic magnitudes 6.57 and 6.62. Its visual apparent magnitude is about 6.54.

    <span class="mw-page-title-main">V602 Carinae</span> Star in the constellation Carina

    V602 Carinae is a red supergiant and variable star of spectral type M3 in the constellation Carina. It is considered to be one of largest known stars, being around 1,000 times larger than the Sun.

    <span class="mw-page-title-main">PZ Cassiopeiae</span> Star in the constellation Cassiopeia

    PZ Cassiopeiae is a red supergiant star located in the constellation of Cassiopeia, and a semi-regular variable star.

    <span class="mw-page-title-main">Sigma Ophiuchi</span> Star in the constellation Ophiuchus

    Sigma Ophiuchi, Latinized from σ Ophiuchi, is a single, orange-hued star in the equatorial constellation Ophiuchus. Its apparent visual magnitude is 4.31, which is bright enough to be faintly visible to the naked eye. The annual parallax shift of 3.62 mas as seen from Earth provides a distance estimate of roughly 900 light years. It is moving closer to the Sun with a radial velocity of −28 km/s.

    <span class="mw-page-title-main">V1073 Scorpii</span> Variable star in the constellation Scorpius

    V1073 Scorpii is a variable star in the constellation Scorpius. It has a non-Greek Bayer designation of k Scorpii. The star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around +4.87. Parallax measurements yield a distance estimate of approximately 2,920 ly (896 pc) from the Sun, and it is drifting further away with a radial velocity of +7 km/s. It has an absolute magnitude of −6.8

    <span class="mw-page-title-main">UY Scuti</span> Star in the constellation Scutum

    UY Scuti (BD-12°5055) is a red supergiant star, located 5,900 light-years away in the constellation Scutum. It is also a pulsating variable star, with a maximum brightness of magnitude 8.29 and a minimum of magnitude 10.56, which is too dim for naked-eye visibility. It is considered to be one of the largest known stars, with a radius estimated at 909 solar radii, thus a volume of 750 million times that of the Sun. This estimate implies if it were placed at the center of the Solar System, its photosphere would extend past the orbit of Mars or even the asteroid belt.

    <span class="mw-page-title-main">V915 Scorpii</span> Variable star in the constellation Scorpius

    V915 Scorpii is a hypergiant and semiregular variable star, located 1,718 parsecs (5,600 ly) away in the constellation Scorpius. Its apparent magnitude varies between 6.22 and 6.64, being heavily diminshed by 2.93 magnitudes due to interstellar extinction. When it is at its brightest, it is very faintly visible to the naked eye under excellent observing conditions.

    <span class="mw-page-title-main">CK Carinae</span> Red supergiant star in the constellation Carina

    CK Carinae is a variable star in the constellation Carina, the keel of Argo Navis. It is a member of the star association Carina OB1-D, at a distance of around 2,300 parsecs or 7,500 light years.

    <span class="mw-page-title-main">BO Carinae</span> Star in the constellation Carina

    BO Carinae, also known as HD 93420, is an irregular variable star in the constellation Carina.

    <span class="mw-page-title-main">Stephenson 2 DFK 1</span> Star in the open cluster Stephenson 2

    Stephenson 2 DFK 1, also known as RSGC2-01 or St2-18, is a red supergiant (RSG) or possible extreme red hypergiant (RHG) star in the constellation of Scutum. It lies near the open cluster Stephenson 2, which is located about 5.8 kiloparsecs away from Earth in the Scutum–Centaurus Arm of the Milky Way galaxy, and is assumed to be one of a group of stars at a similar distance, although some studies consider it to be an unrelated or foreground red supergiant.

    <span class="mw-page-title-main">Westerlund 1-75</span> Red supergiant in the Westerlund 1 super star cluster

    Westerlund 1 W75 or Wd 1-75 is a red supergiant (RSG) located in the Westerlund 1 super star cluster. Its radius is calculated to be around 668 solar radii (4.65 × 108 km, 3.10 au). This corresponds to a volume 298 million times bigger than the Sun. If placed at the center of the Solar System, Westerlund 1-75 would engulf the inner limits of the asteroid belt.

    <span class="mw-page-title-main">MZ Puppis</span> Red supergiant star in the constellation of Puppis

    MZ Puppis is a red supergiant star in the constellation of Puppis. It has a radius of 400 R and a mass of 14 solar masses, similar to Betelgeuse.

    <span class="mw-page-title-main">12 Pegasi</span> K-type supergiant star in the constellation of Pegasus

    12 Pegasi is a K-type supergiant star in the constellation of Pegasus. It has a spectral type of K0Ib Hdel0.5, which indicates that it is a less luminous K-type supergiant with strong H-δ Balmer lines. The star has expanded to 81 times the radius of the Sun, and has an effective temperature of 4,185 K.

    References

    1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
    2. 1 2 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): 1721–1734. arXiv: astro-ph/0608438 . Bibcode:2006MNRAS.372.1721K. doi: 10.1111/j.1365-2966.2006.10973.x . S2CID   5203133.
    3. 1 2 Samus, N. N.; Durlevich, O. V.; 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. 1 2 3 4 5 6 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. S2CID   73575062.
    5. Gontcharov, G. A. (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.
    6. 1 2 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. S2CID   7603031.
    7. 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.
    8. 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. arXiv: 2312.12521 . Bibcode:2024A&A...683A..19G. doi:10.1051/0004-6361/202348047. ISSN   0004-6361.
    9. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
    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 (1): 273–289. arXiv: astro-ph/0504379 . Bibcode:2005A&A...438..273V. doi:10.1051/0004-6361:20042555. S2CID   16724272.
    11. 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.
    12. 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. arXiv: 2312.12521 . Bibcode:2024A&A...683A..19G. doi:10.1051/0004-6361/202348047. ISSN   0004-6361.