S Persei

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S Persei
Double Cluster.jpg
GoldF39400 circle.svg
Location of S Persei (circled) near the Double Cluster (north is left)
Observation data
Epoch J2000       Equinox J2000
Constellation Perseus
Right ascension 2h 22m 51.70928s [1]
Declination 58° 31′ 11.4476″ [1]
Apparent magnitude  (V)+9.23 [2] (7.9 - 12.0 [3] )
Characteristics
Spectral type M3 Iae–M7 [3]
B−V color index +2.65 [2]
Variable type SRc [3]
Astrometry
Radial velocity (Rv)-39.71 [4]  km/s
Proper motion (μ)RA: –0.49 ± 0.23 [5]   mas/yr
Dec.: −1.19 ± 0.20 [5]   mas/yr
Parallax (π)0.413 ± 0.017  mas [5]
Distance 7,900 ± 300  ly
(2,420 ± 100  pc)
Absolute magnitude  (MV)–6.36 (at mV 9.23) [2]
Details
Mass 20 [6]   M☉
Radius 1,298+64
−57 [7]  –1,364±6 [8]   R☉
Luminosity 123,000 [9] – 186,000 [10]   L☉
Surface gravity (log g)0.0 [11]   cgs
Temperature 3,000 [12] – 3,600 [10]   K
Other designations
S Per, HD 14528, HIP 11093, BD+57°552, SAO 23261, WDS J02229+5835, AAVSO 0215+58
Database references
SIMBAD data

S Persei is a red supergiant or hypergiant located near the Double Cluster in Perseus, north of the cluster NGC 869. It is a member of the Perseus OB1 association and one of the largest known stars. If placed in the Solar System, its photosphere would engulf the orbit of Jupiter. It is also a semiregular variable, a star whose variations are less regular than those of Mira variables.

Contents

Discovery

S Persei was named by German astronomer Adalbert Krueger in 1874 after observing that it varied in brightness. [13] It was subsequently listed in major stellar catalogues of that era as HD  14528 and BD+57°552.

Variability

A visual band light curve for S Persei, plotted from AAVSO data SPerLightCurve.png
A visual band light curve for S Persei, plotted from AAVSO data

S Persei varies slowly by several magnitudes, a factor of over 40 in brightness. It has a main period of somewhat over two years, but shows significant unpredictability. There is a strong variation in the amplitude from around one magnitude to about four magnitudes, and these have been interpreted as beats due to a second period of about 940 days. [15] Other analyses find only the primary period of 813 ± 60 days. [16]

S Persei is classified as a semiregular variable star of type SRc, indicating that it is a supergiant, and it has one of the largest visual amplitudes of any variable of this type. [3] While the General Catalogue of Variable Stars lists it as varying between magnitudes 7.9 and 12.0, it has since been seen fainter. [16]

The spectral type of S Persei also varies. Typically it is a red supergiant of spectral class M3 or M4, but particularly at deep visual minima it may show a much cooler spectral type of M7 or M8, highly unusual for a supergiant. [17]

Properties

Many of the visually bright variable stars belong to this class of semiregulars, as these stars are extremely large and luminous, and hence visible across long distances. S Persei has been described as a hypergiant [18] and has a radius over 700 times the sun's radius (R☉). [2] Its angular diameter has been measured directly and found to be somewhat elliptical. Modelled as a uniform disk, the radius corresponds to 1,212 ± 124 R☉. [19]

The temperature has been calculated from the spectrum using a DUSTY model, [20] giving an effective photospheric temperature of 3,500 K and a temperature of 1,000 K for the surrounding dust torus. [21] This is consistent with previous studies, but the derived luminosity from different authors varies from 86,000 L☉ to 186,000 L☉. [10] [22] [23] Older studies frequently calculated higher luminosities, lower temperatures, and consequently larger values for the radius. [24]

The mass of S Persei is also uncertain, but expected to be around 20 M☉. [6] Mass is being lost at 2.4 to 2.6×10−5 M☉ per year, [21] leading to an extensive and complex circumstellar environment of gas and dust. [10]

Location

S Persei is surrounded by clouds containing water molecules which produce maser emission. This allows the distance to be measured very accurately using very long baseline interferometry, giving an annual parallax of 0.413 ± 0.017 milliarcseconds. For comparison the Gaia Data Release 2 parallax is 0.2217±0.1214  mas . [25] It lies somewhat further away than the centres of the Double Cluster open clusters, but definitely within the Per OB1 association and the Perseus Arm of the galaxy. [5]

S Persei is a double star. The red supergiant has an A0 11th magnitude companion at 69". [26] There are also several other 8th to 10th magnitude stars within half a degree of S Persei. [27]

Related Research Articles

<span class="mw-page-title-main">Red supergiant</span> Stars with a supergiant luminosity class with a spectral type of K or M

Red supergiants (RSGs) are stars with a supergiant luminosity class and a stellar classification K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Antares A are the brightest and best known red supergiants (RSGs), indeed the only first magnitude red supergiant stars.

<span class="mw-page-title-main">KY Cygni</span> Star in the constellation Cygnus

KY Cygni is a red supergiant of spectral class M3.5Ia located in the constellation Cygnus. It is approximately 4,700 light-years away.

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

Phi Cassiopeiae is a multiple star in the constellation Cassiopeia with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".

<span class="mw-page-title-main">Yellow hypergiant</span> Class of massive star with a spectral type of A to K

A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass. They are amongst the most visually luminous stars, with absolute magnitude (MV) around −9, but also one of the rarest, with just 20 known in the Milky Way and six of those in just a single cluster. They are sometimes referred to as cool hypergiants in comparison with O- and B-type stars, and sometimes as warm hypergiants in comparison with red supergiants.

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">Westerlund 1</span> Super star cluster in the Milky Way Galaxy

Westerlund 1 is a compact young super star cluster about 3.8 kpc away from Earth. It is thought to be the most massive young star cluster in the Milky Way, and was discovered by Bengt Westerlund in 1961 but remained largely unstudied for many years due to high interstellar absorption in its direction. In the future, it will probably evolve into a globular cluster.

<span class="mw-page-title-main">MY Cephei</span> Red supergiant star in the constellation Cepheus

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<span class="mw-page-title-main">Hypergiant</span> Rare star with tremendous luminosity and high rates of mass loss by stellar winds

A hypergiant (luminosity class 0 or Ia+) is a very rare type of star that has an extremely high luminosity, mass, size and mass loss because of its extreme stellar winds. The term hypergiant is defined as luminosity class 0 (zero) in the MKK system. However, this is rarely seen in literature or in published spectral classifications, except for specific well-defined groups such as the yellow hypergiants, RSG (red supergiants), or blue B(e) supergiants with emission spectra. More commonly, hypergiants are classed as Ia-0 or Ia+, but red supergiants are rarely assigned these spectral classifications. Astronomers are interested in these stars because they relate to understanding stellar evolution, especially star formation, stability, and their expected demise as supernovae. Notable examples of hypergiants include the Pistol Star, a blue hypergiant located close to the Galactic Center and one of the most luminous stars known; Rho Cassiopeiae, a yellow hypergiant that is one of the brightest to the naked eye; and Mu Cephei (Herschel's "Garnet Star"), one of the largest and brightest stars known.

<span class="mw-page-title-main">VX Sagittarii</span> Asymptotic giant branch star in the constellation Sagittarius

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<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">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">Westerlund 1 W26</span> Star in the constellation Ara

Westerlund 1 W26 or Westerlund 1 BKS AS is a red supergiant located at the outskirts of the Westerlund 1 super star cluster. It is one of the largest known stars and the most luminous supergiant stars discovered so far with radius calculated to be in excess of a thousand times the solar radius, and a luminosity of over 200,000 times the solar luminosity. If placed at the center of the Solar System, its photosphere would engulf the orbit of Jupiter.

AH Scorpii 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.

<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">HR 5171</span> Star in the constellation Centaurus

HR 5171, also known as V766 Centauri, is a yellow hypergiant in the constellation Centaurus. It is said to be either an extreme red supergiant (RSG) or recent post-red supergiant (Post-RSG) yellow hypergiant (YHG), both of which suggest it is one of the largest known stars. The star's diameter is uncertain but likely to be between 1,100 and 1,600 times that of the Sun, while its distance is 3.6 kpc from Earth.

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

RS Persei is a red supergiant variable star located in the Double Cluster in Perseus. The star's apparent magnitude varies from 7.82 to 10.0, meaning it is never visible to the naked eye.

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

XX Persei is a semiregular variable red supergiant star in the constellation Perseus, between the Double Cluster and the border with Andromeda.

<span class="mw-page-title-main">Westerlund 1-20</span> Red supergiant star located in the Westerlund 1 super star cluster

Westerlund 1-20 (abbreviated to Wd 1-20 or just W20) is a red supergiant (RSG) located in the Westerlund 1 super star cluster. Its radius was calculated to be around 965 solar radii (6.72 × 108 km, 4.48 au), making it one of the largest stars discovered so far. This corresponds to a volume 899 million times bigger than the Sun. If placed at the center of the Solar System, the photosphere of Westerlund 1-20 would almost reach the orbit of Jupiter.

<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.

Stephenson 2 DFK 49 or St2-11 is a putative post red supergiant star in the constellation Scutum, in the massive open cluster Stephenson 2. It is possibly one of the largest known stars with a radius estimated to be between 1,074 solar radii to 1,300 solar radii, corresponding to volumes of 1.2 and 2.2 times that of the Sun respectively. If it was placed at the center of the Solar System, its photosphere would potentially approach or engulf Jupiter's orbit. It loses mass at a very high rate, resulting in large amounts of infrared excess.

References

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  2. 1 2 3 4 Emily M. Levesque; Philip Massey; K. A. G. Olsen; Bertrand Plez; et al. (August 2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv: astro-ph/0504337 . Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID   15109583.
  3. 1 2 3 4 Samus', N. N.; Goranskii, V. P.; Durlevich, O. V.; Zharova, A. V.; Kazarovets, E. V.; Kireeva, N. N.; Pastukhova, E. N.; Williams, D. B.; Hazen, M. L. (2003). "An Electronic Version of the Second Volume of the General Catalogue of Variable Stars with Improved Coordinates". Astronomy Letters. 29 (7): 468. Bibcode:2003AstL...29..468S. doi:10.1134/1.1589864. S2CID   16299532.
  4. ↑ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data". Astronomy and Astrophysics. 430 (1): 165–186. arXiv: astro-ph/0409579 . Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. ISSN   0004-6361. S2CID   17804304.
  5. 1 2 3 4 Asaki, Y.; Deguchi, S.; Imai, H.; Hachisuka, K.; Miyoshi, M.; Honma, M. (2010). "Distance and Proper Motion Measurement of the Red Supergiant, S Persei, with Vlbi H2O Maser Astrometry". The Astrophysical Journal. 721 (1): 267–277. arXiv: 1007.4874 . Bibcode:2010ApJ...721..267A. doi:10.1088/0004-637X/721/1/267. ISSN   0004-637X. S2CID   119183897.
  6. 1 2 Yates, J. A.; Cohen, R. J. (1994). "Circumstellar Envelope Structure of Late Type Stars as Revealed by MERLIN Observations of 22-GHZ Water Masers". Monthly Notices of the Royal Astronomical Society. 270 (4): 958. Bibcode:1994MNRAS.270..958Y. doi: 10.1093/mnras/270.4.958 .
  7. ↑ Norris, Ryan (2023). "Student Science at NMT: Learning Optical Interferometry Through Projects on Evolved Stars" (PDF). CHARA.
  8. ↑ Norris, Ryan (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PhD thesis). Georgia State University. doi:10.57709/15009706.
  9. ↑ Davies, Ben; Beasor, Emma R. (March 2020). "The 'red supergiant problem': the upper luminosity boundary of Type II supernova progenitors". MNRAS . 493 (1): 468–476. arXiv: 2001.06020 . Bibcode:2020MNRAS.493..468D. doi: 10.1093/mnras/staa174 . S2CID   210714093.
  10. 1 2 3 4 Fok, Thomas K. T.; Nakashima, Jun-Ichi; Yung, Bosco H. K.; Hsia, Chih-Hao; Deguchi, Shuji (2012). "Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters". The Astrophysical Journal. 760 (1): 65. arXiv: 1209.6427 . Bibcode:2012ApJ...760...65F. doi:10.1088/0004-637X/760/1/65. S2CID   53393926.
  11. ↑ Gonzalez, Guillermo; Wallerstein, George (2000). "Elemental Abundances in Evolved Supergiants. II. The Young Clusters H and χ Persei". The Astronomical Journal. 119 (4): 1839. Bibcode:2000AJ....119.1839G. doi: 10.1086/301319 .
  12. ↑ García-Hernández, D. A.; García-Lario, P.; Plez, B.; Manchado, A.; d'Antona, F.; Lub, J.; Habing, H. (2007). "Lithium and zirconium abundances in massive Galactic O-rich AGB stars". Astronomy and Astrophysics. 462 (2): 711. arXiv: astro-ph/0609106 . Bibcode:2007A&A...462..711G. doi:10.1051/0004-6361:20065785. S2CID   16016698.
  13. ↑ Krüger, A. (1874). "Anzeige eines neuen veränderlichen Sternes (S Persei)". Astronomische Nachrichten. 83 (10): 157–158. Bibcode:1874AN.....83..157K. doi:10.1002/asna.18740831005.
  14. ↑ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  15. ↑ Smith, Horace A. (1974). "S Persei a Semi-Regular Variable with Two Periods". Journal of the American Association of Variable Star Observers. 3 (1): 20. Bibcode:1974JAVSO...3...20S.
  16. 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.
  17. ↑ Wing, R. F. (2009). "The Biggest Stars of All". The Biggest. 412: 113. Bibcode:2009ASPC..412..113W.
  18. ↑ Zhang, B.; Reid, M. J.; Menten, K. M.; Zheng, X. W.; Brunthaler, A. (2012). "The distance and size of the red hypergiant NML Cygni from VLBA and VLA astrometry". Astronomy & Astrophysics. 544: A42. arXiv: 1207.1850 . Bibcode:2012A&A...544A..42Z. doi:10.1051/0004-6361/201219587. ISSN   0004-6361. S2CID   55509287.
  19. ↑ Thompson, R. R.; Creech-Eakman, M. J. (2003). "Interferometric observations of the supergiant S Persei: Evidence for axial symmetry and the warm molecular layer". American Astronomical Society Meeting 203. 203: 49.07. Bibcode:2003AAS...203.4907T.
  20. ↑ Ivezic, Zeljko; Nenkova, Maia; Elitzur, Moshe (1999). "User Manual for DUSTY". arXiv: astro-ph/9910475 .
  21. 1 2 Gordon, Michael S.; Humphreys, Roberta M.; Jones, Terry J.; Shenoy, Dinesh; Gehrz, Robert D.; Helton, L. Andrew; Marengo, Massimo; Hinz, Philip M.; Hoffmann, William F. (2018). "Searching for Cool Dust. II. Infrared Imaging of the OH/IR Supergiants, NML Cyg, VX SGR, S Per, and the Normal Red Supergiants RS per and T per". The Astronomical Journal. 155 (5): 212. arXiv: 1708.00018 . Bibcode:2018AJ....155..212G. doi: 10.3847/1538-3881/aab961 . S2CID   73650032.
  22. ↑ Mauron, N.; Josselin, E. (2011). "The mass-loss rates of red supergiants and the de Jager prescription". Astronomy and Astrophysics. 526: A156. arXiv: 1010.5369 . Bibcode:2011A&A...526A.156M. doi:10.1051/0004-6361/201013993. S2CID   119276502.
  23. ↑ Verhoelst, T.; Van Der Zypen, N.; Hony, S.; Decin, L.; Cami, J.; Eriksson, K. (2009). "The dust condensation sequence in red supergiant stars". Astronomy and Astrophysics. 498 (1): 127–138. arXiv: 0901.1262 . Bibcode:2009A&A...498..127V. doi:10.1051/0004-6361/20079063. S2CID   18383796.
  24. ↑ De Jager, C.; Nieuwenhuijzen, H.; Van Der Hucht, K. A. (1988). "Mass loss rates in the Hertzsprung-Russell diagram". Astronomy and Astrophysics Supplement Series. 72: 259. Bibcode:1988A&AS...72..259D.
  25. ↑ 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 .
  26. ↑ Dommanget, J.; Nys, O. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Communications de l'Observatoire Royal de Belgique. 115: 1. Bibcode:1994CoORB.115....1D.
  27. ↑ Skiff, B. A. (1994). "Photometry of Stars in the Field of S Persei". Information Bulletin on Variable Stars. 4054: 1. Bibcode:1994IBVS.4054....1S.
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