RSGC1

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RSGC1
Ssc2006-03a.jpg
Spitzer image of RSGC1
Observation data (J2000 epoch)
Right ascension 18h 36m 29s [1]
Declination −06° 52′ 48″ [1]
Distance 22.0 ± 2.9kly (6.60 ± 0.89kpc [2] )
Apparent magnitude  (V)not visible [2]
Apparent dimensions (V)~1.5′ [3] [1]
Physical characteristics
Mass~3 × 104 [2]   M☉
Radius1.5 ± 0.3 pc [2]
Estimated age12 ± 2 my [2] [1]
Associations
Constellation Scutum
See also: Open cluster, List of open clusters

RSGC1 (Red Supergiant Cluster 1) is a young massive open cluster in the Milky Way galaxy. It was discovered in 2006 in the data generated by several infrared surveys, named for the unprecedented number of red supergiant members. [3] The cluster is located in the constellation Scutum at the distance of about 6.6  kpc from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the Scutum–Centaurus Arm—one of its two major spiral arms. [4]

Contents

The age of RSGC1 is estimated at 10–14 million years. The cluster is heavily obscured and has not been detected in visible light. It lies close to other groupings of red supergiants known as Stephenson 2, RSGC3, Alicante 7, Alicante 8, and Alicante 10. The mass of RSGC1 is estimated at 30 thousand solar masses, which makes it one of the most massive open clusters in the Galaxy. [2]

The observed red supergiants with the mass of about 16–20 solar masses are type II supernova progenitors. [2] Over 200 main sequence stars have been detected with masses over 8 M☉, which allows the distance to be determined from main sequence fitting. Fourteen red supergiant members have been identified. [1]

Members

Prominent supergiants [2] [5]
StarSpectral typeMagnitude (K band)Temperature (effective, K)Absolute magnitudeLuminosity (L☉)Radius (R☉)
F01 M3 / M5 [6] 4.9623,550 [6] −11.75335,000 [6] 1450 [7] -1,530+330
−424 [6]
F02 M4 / M2 [6] 5.0293,700 [6] −11.92215,000 [6] 1,128 [6]
F03M4 / M5 [6] 5.3333,500 [6] −11.28120,000 [6] 942 [6]
F04M0 / M1 [6] 5.3423,800 [6] −11.24380,000 [6] 1,422 [6]
F05M6 / M4 [6] 5.5353,500 [6] −11.36190,000 [6] 1,185 [6]
F06M5 [6] 5.6133,400 [6] −10.70230,000 [6] 1,382 [6]
F07M2 / M3 [6] 5.6313,600 [2] - 3,800 [6] −10.81190,000 [6] 1,006 [6]
F08M3 [6] 5.6543,600 [6] −11.33200,000 [6] 1,150 [6]
F09M3 / M6 [6] 5.6703,600 [6] −10.92150,000 [6] 996 [6]
F10M5 / M3 [6] 5.7093,600 [6] −10.86235,000 [6] 1,246 [6]
F11M1 / M4 [6] 5.7223,800 [6] −11.03200,000 [6] 1,032 [6]
F12 [3] M0 [6] 5.8643,900 [6] −10.70190,000 [6] 955 [6]
F13 M3 / K2 [6] 5.9574,200 [6] −11.39290,000 [6] 1,017 [6]
F14M3 / M1 [6] 6.1673,700 [6] −10.2574,000 [6] [2] 662 [6]
F15G0 / G6 [6] 6.6826,850 [2] −10.07229,000 [2] - 620,000 [6] 340 [2]

RSGC1-F01

RSGC1-F01 is a red supergiant located in RSGC1. The radius was calculated to be around 1,450 [7] -1,530 [6] times that of the Sun (the radius is calculated by applying the Stefan-Boltzmann law), making it one of the largest stars discovered so far. This corresponds to a volume 3.58 billion times bigger than the Sun. If placed at the center of the Solar System, the photosphere would engulf the orbit of Jupiter.

RSGC1-F02

RSGC1-F02 is a red supergiant located in the RSGC1. Its radius was calculated to be between 1,499 [2] and 1,549 [5] or 1,128 [6] times that of the Sun (the radius is calculated applying the Stefan-Boltzmann law), making it one of the largest stars discovered so far. This corresponds to a volume 3.37 and 3.72 billion times bigger than the Sun. If placed at the center of the Solar System, its photosphere would engulf the orbit of Jupiter.

RSGC1-F13

RSGC1-F13 is a peculiar red supergiant which is unusually red compared to the other stars. [7] It is notable for having the highest mass-loss rate in the cluster at (2.7±0.8)×10−5 M☉/yr. [6] The star also has detected masers of SiO, H2O, and OH. [6] ALMA detects CO emission in F13 along with four other supergiants in the cluster extending hundreds of stellar radii away from the stars. [7] The CO mass loss rate is estimated to be 4.2×10−5 M☉/yr, which is an order of magnitude larger than the predicted value for the other red supergiants in the study. [7] F13 is compared with VY Canis Majoris as a similarly extreme red supergiant, both displaying stronger and possibly eruptive mass-loss. [7]

Related Research Articles

<span class="mw-page-title-main">Scutum (constellation)</span> Small constellation in the southern celestial hemisphere

Scutum is a small constellation. Its name is Latin for shield, and it was originally named Scutum Sobiescianum by Johannes Hevelius in 1684. Located just south of the celestial equator, its four brightest stars form a narrow diamond shape. It is one of the 88 IAU designated constellations defined in 1922.

<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 of spectral type 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">Scutum–Centaurus Arm</span> Spiral arm of the Milky Way

The Scutum–Centaurus Arm, also known as Scutum-Crux arm, is a long, diffuse curving streamer of stars, gas and dust that spirals outward from the proximate end of the Milky Way's central bar. The Milky Way has been posited since the 1950s to have four spiral arms — numerous studies contest or nuance this number. In 2008, observations using the Spitzer Space Telescope failed to show the expected density of red clump giants in the direction of the Sagittarius and Norma arms. In January 2014, a 12-year study into the distribution and lifespan of massive stars and a 2013-reporting study of the distribution of masers and open clusters both found corroboratory, though would not state irrefutable, evidence for four principal spiral arms.

<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.

<span class="mw-page-title-main">Yellow supergiant</span> Star that has a supergiant luminosity class, with a spectral type of F or G

A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class. They are stars that have evolved away from the main sequence, expanding and becoming more luminous.

<span class="mw-page-title-main">S Persei</span> Red supergiant or hypergiant variable star in the constellation Perseus

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.

<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.

RSGC3 is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2010 in the GLIMPSE survey data. The cluster is located in the constellation Scutum at the distance of about 7 kpc from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the Scutum–Centaurus Arm—one of its two major spiral arms.

<span class="mw-page-title-main">Stephenson 2</span> Massive open cluster in the constellation Scutum

Stephenson 2, also known as RSGC2, is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 1990 as a cluster of red supergiants in a photographic, deep infrared survey by the astronomer Charles Bruce Stephenson, after whom the cluster is named. It is located in the constellation Scutum at the distance of about 6 kpc from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the Scutum–Centaurus Arm—one of the two major spiral arms.

<span class="mw-page-title-main">Melnick 42</span> Massive blue supergiant star in the constellation Dorado

Melnick 42 is a massive blue supergiant star in the Tarantula Nebula in the Large Magellanic Cloud located in the constellation Dorado. Although it is only 21 times the size of the sun, its high temperature of 47,300 K makes it one of the most luminous stars of the Tarantula Nebula at 3,600,000 L☉. It is less than two parsecs from the centre of the R136 cluster, although that is well outside the central core.

<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.

<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 Stephenson 2-18, 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. It is potentially among the largest known stars, one of the most luminous red supergiants, and one of the most luminous stars in the Milky Way.

<span class="mw-page-title-main">Westerlund 1-237</span> Possible red supergiant in the Westerlund 1 super star cluster

Westerlund 1-237 or Westerlund 1 BKS B is a possible red supergiant (RSG) in the constellation of Ara. It is one out of four known red supergiants in the Westerlund 1 super star cluster, although its outlying position, spectrum, and parallax, suggest it could be a foreground giant. As a red supergiant, it would be one of the largest known stars and one of the most luminous of its type.

<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.

Alicante 10, also known as RSGC6, is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2012 in the 2MASS survey data. Currently, eight red supergiants have been identified in this cluster. Alicante 10 is located in the constellation Scutum at the distance of about 6000 pc from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the Scutum–Centaurus Arm—one of the two major spiral arms.

<span class="mw-page-title-main">V1936 Aquilae</span> Blue supergiant star in the constellation Aquila

V1936 Aquilae is a blue supergiant and candidate Luminous blue variable located in the nebula Westerhout 51, in the constellation Aquila, about 20,000 light years away. The star was originally identified as a massive star in 2000, and was thought to be an O-type supergiant. However, subsequent analyses have shown it to be not O but B-type, as well as being possibly an LBV.

<span class="mw-page-title-main">IRAS 18357–0604</span> Star in the constellation Scutum

IRAS 18357–0604 is a yellow hypergiant (YHG) star located in the constellation of Scutum, estimated to be about 19,600 light years, or 6,000 parsecs, away. IRAS 18357–0604 is remarkably similar to IRC +10420, another yellow hypergiant in the constellation of Aquila.

Stephenson 2 DFK 49 or St2-11 is a putative post red supergiant star in the constellation Scutum. It is located in the massive open cluster Stephenson 2. It is possibly one of the largest known stars with radius estimates ranging from 884 solar radii to 1,300 solar radii. If the upper estimate is correct, then Stephenson 2 DFK 49 has a volume 2.2 billion times that of the Sun. If it was placed at the center of the Solar System, its photosphere will potentially approach or engulf Jupiter's orbit. It loses mass at a very high rate, resulting in large amounts of Infrared excess.

References

  1. 1 2 3 4 5 Froebrich, D.; Scholz, A. (2013). "The main sequence of three red supergiant clusters". Monthly Notices of the Royal Astronomical Society. 436 (2): 1116–1122. arXiv: 1308.6436 . Bibcode:2013MNRAS.436.1116F. doi:10.1093/mnras/stt1633. ISSN   0035-8711. S2CID   31935943.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Davies, B.; Figer, D. F.; Law, C. J.; Kudritzki, R. P.; Najarro, F.; Herrero, A.; MacKenty, J. W. (2008). "The Cool Supergiant Population of the Massive Young Star Cluster RSGC1". The Astrophysical Journal . 676 (2): 1016–1028. arXiv: 0711.4757 . Bibcode:2008ApJ...676.1016D. doi: 10.1086/527350 . ISSN   0004-637X. S2CID   15639297.
  3. 1 2 3 Figer, D. F.; MacKenty, J. W.; Robberto, M.; Smith, K.; Najarro, F.; Kudritzki, R. P.; Herrero, A. (2006). "Discovery of an Extraordinarily Massive Cluster of Red Supergiants". The Astrophysical Journal. 643 (2): 1166–1179. arXiv: astro-ph/0602146 . Bibcode:2006ApJ...643.1166F. doi:10.1086/503275. S2CID   18241900.
  4. ↑ Davies, B.; Figer, D. F.; Kudritzki, R. P.; MacKenty, J.; Najarro, F.; Herrero, A. (2007). "A Massive Cluster of Red Supergiants at the Base of the Scutum‐Crux Arm". The Astrophysical Journal. 671 (1): 781–801. arXiv: 0708.0821 . Bibcode:2007ApJ...671..781D. doi:10.1086/522224. S2CID   1447781.
  5. 1 2 Fok, Thomas K. T.; Nakashima, Jun-ichi; Yung, Bosco H. K.; Hsia, Chih-Hao; Deguchi, Shuji (2012-11-20). "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. hdl: 10722/181706 . ISSN   0004-637X. S2CID   53393926.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Humphreys, Roberta M.; Helmel, Greta; Jones, Terry J.; Gordon, Michael S. (August 2020). "Exploring the Mass Loss Histories of the Red Supergiants". The Astronomical Journal . 160 (3): 145. arXiv: 2008.01108 . Bibcode:2020AJ....160..145H. doi: 10.3847/1538-3881/abab15 . S2CID   220961677.
  7. 1 2 3 4 5 6 Decin, Leen; Richards, Anita M. S.; Marchant, Pablo; Sana, Hugues (17 March 2023). "ALMA detection of CO rotational line emission in red supergiant stars of the massive young star cluster RSGC1 -- Determination of a new mass-loss rate prescription for red supergiants". arXiv: 2303.09385 [astro-ph.SR].
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