V957 Scorpii

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V957 Scorpii
Scorpius constellation map.svg
Red circle.svg
Location of V957 Scorpii (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Scorpius
Right ascension 17h 52m 13.662s [1]
Declination −34° 47′ 57.11″ [1]
Apparent magnitude  (V)5.87 [2]
Characteristics
Spectral type B5 IIIp [3]
U−B color index −0.64 [4]
B−V color index −0.10 [4]
Variable type SX Ari [2]
Astrometry
Radial velocity (Rv)−9.70 [5]  km/s
Proper motion (μ)RA: 3.148 [1]   mas/yr
Dec.: −5.604 [1]   mas/yr
Parallax (π)3.6766 ± 0.1521  mas [1]
Distance 890 ± 40  ly
(270 ± 10  pc)
Absolute magnitude  (MV)−1.441 [6]
Details
Mass 5.13 [7]   M☉
Radius 4.00 [7]   R☉
Luminosity 1,148 [7]   L☉
Surface gravity (log g)3.94 [7]   cgs
Temperature 16,600 [7]   K
Metallicity [Fe/H]+0.01 [8]   dex
Rotational velocity (v sin i)30 [9]  km/s
Age 50 [7]   Myr
Other designations
V957  Sco, HR  6647, HD  162374, CD−34°12165, SAO  209383, HIP  87460
Database references
SIMBAD data

V957 Scorpii is a variable star in the constellation of Scorpius. It is a blue straggler in the open cluster Messier 7, a star that is unexpectedly hot compared to other members of the cluster.

Contents

Spectrum

Messier 7 (M7), with V957 Scorpii the bright star to the right of the central square Messier 7.jpg
Messier 7 (M7), with V957 Scorpii the bright star to the right of the central square

V957 Scorpii shows a peculiar B5 or B6 spectrum. Its luminosity class has been given as main sequence (V), subgiant (IV), giant (III), and supergiant (Ib). [10] From its position in the H-R diagram, it is actually thought to be a main sequence star. [11] With a helium abundance 25 times lower than that of the sun, [12] it is classified as helium-weak. It also has a low carbon abundance and a strong magnetic field. [7]

Messier 7

A light curve for V957 Scorpii, plotted from TESS data. The inset plot shows the same data averaged over several cycles. V957ScoLightCurve.png
A light curve for V957 Scorpii, plotted from TESS data. The inset plot shows the same data averaged over several cycles.

Messier 7 is a naked-eye open cluster. Except for one obvious orange giant star, its brightest members are mostly early A and late B main sequence stars and giants. Several of them are also chemically peculiar stars. However, two stars are hotter than the others and lie to the left of the isochrone for the cluster. These are the blue stragglers HD 162586 and V957 Scorpii. V957 Scorpii is considered 92% likely to be a member of M7. M7 has an age around 220 million years, but the apparent age of V957 Scorpii is less than 100 million years. [12]

Variability

V957 Scorpii varies in brightness by about 0.05 magnitudes. This is thought to be due to its rotation and variations in its surface brightness. It is classified as an SX Arietis variable, also known as helium variables. Their spectral lines also vary as the stars rotate. [2]

Related Research Articles

<span class="mw-page-title-main">Lambda Scorpii</span> Triple star system in the constellation Scorpius

Lambda Scorpii is a triple star system and the second-brightest object in the constellation of Scorpius. It is formally named Shaula; Lambda Scorpii is its Bayer designation, which is Latinised from λ Scorpii and abbreviated Lambda Sco or λ Sco. With an apparent visual magnitude of 1.62, it is one of the brightest stars in the night sky.

R Apodis is a star in the constellation Apus.

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<span class="mw-page-title-main">R Centauri</span> Variable star in the constellation Centaurus

R Centauri is a Mira variable star in the constellation Centaurus.

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

Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

<span class="mw-page-title-main">HD 155035</span> Star in the constellation Ara

HD 155035 is the Henry Draper Catalogue designation for a star in the constellation Ara, the Altar. It is located at a distance of approximately 1,450 light-years from Earth and has an apparent visual magnitude of 5.92, making it is faintly visible to the naked eye. This is a red giant star with a stellar classification of M1.5 III. It an irregular variable that changes brightness over an amplitude range of 0.12 magnitudes.

<span class="mw-page-title-main">HD 168607</span> Star in the constellation Sagittarius

HD 168607 is a blue hypergiant and luminous blue variable (LBV) star located in the constellation of Sagittarius, easy to see with amateur telescopes. It forms a pair with HD 168625, also a blue hypergiant and possible luminous blue variable, that can be seen at the south-east of M17, the Omega Nebula.

<span class="mw-page-title-main">1 Camelopardalis</span> Double star system in the constellation Camelopardalis

1 Camelopardalis is a double star system in the constellation Camelopardalis. Its combined apparent magnitude is 5.56 and it is approximately 800 parsecs (2,600 ly) away.

<span class="mw-page-title-main">WR 24</span> Wolf-Rayet star in the constellation Carina

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<span class="mw-page-title-main">24 Scorpii</span> Star in the constellation Ophiuchus

24 Scorpii is a star that was originally placed by John Flamsteed within the constellation of Scorpius but in now placed within the southeastern constellation of Ophiuchus. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 4.91. Based on the trigonometric parallax published in Gaia Data Release 2, the star lies approximately 121 parsecs or 390 light years away. It is positioned near the ecliptic and thus is subject to lunar occultations.

<span class="mw-page-title-main">31 Orionis</span> Binary star in the constellation Orion

31 Orionis is a binary star system in the equatorial constellation of Orion, located near the bright star Mintaka. It is visible to the naked eye as a faint, orange-hued point of light with a baseline apparent visual magnitude of 4.71. The distance to this system is approximately 490 light years away based on parallax, and it is drifting further away with a mean radial velocity of +6 km/s.

<span class="mw-page-title-main">24 Persei</span> Aging giant in the constellation Perseus

24 Persei is a star in the northern constellation of Perseus, located around 337 light years from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.94. The object is moving closer to the Earth with a heliocentric radial velocity of −37 km/s.

<span class="mw-page-title-main">QZ Puppis</span> Star in the constellation Puppis

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<span class="mw-page-title-main">29 Persei</span> Star in the constellation Perseus

29 Persei is a single star in the northern constellation of Perseus, located approximately 640 light years away from the Sun based on parallax. It is visible to the naked eye as faint, blue-white hued star with an apparent visual magnitude of 5.16. This object is a member of the Alpha Persei Cluster.

<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">42 Persei</span> Binary star system in the constellation Perseus

42 Persei is a binary star system in the northern constellation of Perseus. It has the Bayer designation n Persei, while 42 Persei is the Flamsteed designation. The system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.11. It is located around 93 parsecs (302 ly) distant from the Sun, but is drifting closer with a radial velocity of −12.4 km/s.

<span class="mw-page-title-main">31 Persei</span> Star in the constellation Perseus

31 Persei is a single star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05. This star is located around 172 parsecs (560 ly) away from the Sun, and it is drifting closer with a radial velocity of −1.6 km/s. It is likely a member of the Alpha Persei Cluster.

<span class="mw-page-title-main">10 Persei</span> Blue-supergiant star in the constellation Perseus

10 Persei is a blue supergiant star in the constellation Perseus. Its apparent magnitude is 6.26 although it is slightly variable.

<span class="mw-page-title-main">V520 Persei</span> Star in the constellation Perseus

V520 Persei is a blue supergiant member of NGC 869, one of the Perseus Double Cluster open clusters. It is an irregular variable star. At a magnitude of 6.55, V520 Persei is the brightest member in either NGC 869 or NGC 884, although the brighter HD 13994 lies in the foreground along the same line of sight.

References

  1. 1 2 3 4 5 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. 1 2 3 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: B/gcvs. Bibcode:2009yCat....102025S.
  3. ↑ Abt, H. A. (1985). "The spectra and ages of blue stragglers". The Astrophysical Journal. 294: L103. Bibcode:1985ApJ...294L.103A. doi:10.1086/184518.
  4. 1 2 Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  5. ↑ Conti, P. S.; Hensberge, G.; Van Den Heuvel, E. P. J.; Stickland, D. J. (1974). "A study of the blue stragglers in Praesepe, M7 and the Hyades cluster". Astronomy and Astrophysics. 34: 393. Bibcode:1974A&A....34..393C.
  6. ↑ Silaj, J.; Landstreet, J. D. (2014). "Accurate age determinations of several nearby open clusters containing magnetic Ap stars". Astronomy and Astrophysics. 566: A132. arXiv: 1407.4531 . Bibcode:2014A&A...566A.132S. doi:10.1051/0004-6361/201321468. S2CID   53370832.
  7. 1 2 3 4 5 6 7 Glagolevskij, Yu. V. (2019). "On Properties of Main Sequence Magnetic Stars". Astrophysical Bulletin. 74 (1): 66. Bibcode:2019AstBu..74...66G. doi:10.1134/S1990341319010073. S2CID   149900274.
  8. ↑ Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv: 1606.08814 . Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. S2CID   118345778.
  9. ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv: 1201.2052 . Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID   55586789.
  10. ↑ Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009- )". VizieR On-line Data Catalog. Bibcode:2014yCat....1.2023S.
  11. ↑ Mermilliod, J. -C (1982). "Stellar content of young open clusters. I. Blue stragglers". Astronomy and Astrophysics. 109: 37. Bibcode:1982A&A...109...37M.
  12. 1 2 Andrievsky, S. M.; Schönberner, D.; Drilling, J. S. (2000). "Blue stragglers in open clusters. Part II". Astronomy and Astrophysics. 356: 517. Bibcode:2000A&A...356..517A.
  13. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
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