View source for RSGC1

{{Infobox globular cluster
| name = RSGC1
| image = [[file:Ssc2006-03a.jpg|300px]]
| caption = Spitzer image of RSGC1
| credit = 
| epoch = [[J2000]]
| constellation = [[Scutum (constellation)|Scutum]]
| ra = {{RA|18|37|58}}<ref name="simbad">SIMBAD Astronomical Database. Results for RSGC1. [http://simbad.u-strasbg.fr/simbad/] Retrieved 2011-05-07.</ref>
| dec = −06&deg;&nbsp;53&prime;&nbsp;0&Prime;<ref name="simbad"/>
| dist_pc = 6.60 ± 0.89[[Parsec|kpc]]<ref name=Davies2008/>
| dist_ly = 22.0 ± 2.9[[Light-year|kly]]
| appmag_v = not visible<ref name=Davies2008/>
| size_v = ~1.5′<ref name=Figer2006/>
| mass_msol = ~3{{Esp|4}}<ref name=Davies2008/>
| radius_ly = 1.5 ± 0.3 pc<ref name=Davies2008/>
| age = 10–14 [[megayear|my]]<ref name=Davies2008/>
| names =
}}

'''RSGC1''' is a massive young open [[star cluster]] in the [[Milky Way]] galaxy. It was discovered in 2006 in the data from [[infrared]] surveys.<ref name=Figer2006>Figer D.F. ''et al'' 2006. Discovery of an extraordinarily massive cluster of red supergiants. ''Astrophysical Journal'' '''643''' (2): 1166–1179. [http://iopscience.iop.org/0004-637X/643/2/1166/]</ref> 

There are 12 red [[supergiant]]s identified so far. These are massive young stars undergoing [[helium burning]] in their cores.<ref>Helium burning: the triple alpha process, which is a set of [[nuclear fusion]] reactions by which three helium-4 nuclei ([[alpha particle]]s) are transformed into [[carbon]].</ref> There is also one yellow [[hypergiant]], and one intermediate. The cluster is in the constellation [[Scutum]] at about 6.6&nbsp;[[Parsec#Parsecs and kiloparsecs|kpc]] from the Sun.<ref name=Davies2008>Davies B. ''et al'' 2008. The cool [[supergiant]] population of the massive young [[star cluster]] RSGC1. ''Astrophysical Journal'' '''676''' (2): 1016–1028. [http://iopscience.iop.org/0004-637X/676/2/1016/]</ref> It is at the intersection of the northern end of the [[Barred spiral galaxy|Long Bar]] of the Milky Way and the inner portion of the [[Scutum–Centaurus Arm]]—one of its two major spiral arms.<ref name=Davies2007>Davies B. ''et al'' 2007. A massive cluster of red supergiants at the base of the Scutum‐Crux arm. ''Astrophysical Journal'' '''671''': 781. [http://iopscience.iop.org/0004-637X/671/1/781/]</ref>

The age of RSGC1 is estimated at 10–14 million years.<ref name=Davies2008/> The observed red supergiants with the mass of about 16–20 [[solar mass]]es will become type II [[supernova]]s.<ref name=Davies2008/> The cluster is heavily obscured and has not been detected in the [[visible light]]. It lies close to other groups of red supergiants known as [[Stephenson 2]], [[RSGC3]] and [[Alicante 8]]. The mass of RSGC1 is estimated at 30 thousand solar masses, which makes it one the most massive open clusters in the Galaxy.<ref name=Davies2008/>

==References==
{{reflist}}


[[Category:Open star clusters]]