| RSGC1 | |
|---|---|
 Spitzer image of RSGC1 | |
| Observation data (J2000epoch) | |
| 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☉ |
| Radius | 1.5 ± 0.3 pc[2] |
| Estimated age | 12 ± 2my[2][1] |
| Associations | |
| Constellation | Scutum |
| See also:Open cluster,List of open clusters | |
RSGC1 (Red Supergiant Cluster 1) is a young massiveopen cluster in theMilky Way galaxy. It was discovered in 2006 in the data generated by several infrared surveys, named for the unprecedented number ofred supergiant members.[3] The cluster is located in the constellationScutum at a distance of about 6.6 kpc from the Sun. It is likely situated at the intersection of the northern end of theLong Bar of the Milky Way and the inner portion of theScutum–Centaurus Arm—one of its two major spiral arms.[4]
The age of RSGC1 is estimated at 10–14 million years. The cluster is heavily obscured and has not been detected invisible light. It lies close to other groupings of red supergiants known asStephenson 2,RSGC3,Alicante 7,Alicante 8, andAlicante 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 16–20solar masses aretype 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]
| Star | Spectral type | Magnitude (K band) | Temperature (effective, K) | Absolute magnitude | Luminosity (L☉) | Radius(R☉) |
|---|---|---|---|---|---|---|
| F01 | M3 / M5[6] | 4.962 | 3,550[6] | −11.75 | 335,000[6] | 1450[7]–1,530+330 −424[6] |
| F02 | M4 / M2[6] | 5.029 | 3,700[6] | −11.92 | 215,000[6] | 1,128[6] |
| F03 | M4 / M5[6] | 5.333 | 3,500[6] | −11.28 | 120,000[6] | 942[6] |
| F04 | M0 / M1[6] | 5.342 | 3,800[6] | −11.24 | 380,000[6] | 1,422[6] |
| F05 | M6 / M4[6] | 5.535 | 3,500[6] | −11.36 | 190,000[6] | 1,185[6] |
| F06 | M5[6] | 5.613 | 3,400[6] | −10.70 | 230,000[6] | 1,382[6] |
| F07 | M2 / M3[6] | 5.631 | 3,600[2]–3,800[6] | −10.81 | 190,000[6] | 1,006[6] |
| F08 | M3[6] | 5.654 | 3,600[6] | −11.33 | 200,000[6] | 1,150[6] |
| F09 | M3 / M6[6] | 5.670 | 3,600[6] | −10.92 | 150,000[6] | 996[6] |
| F10 | M5 / M3[6] | 5.709 | 3,600[6] | −10.86 | 235,000[6] | 1,246[6] |
| F11 | M1 / M4[6] | 5.722 | 3,800[6] | −11.03 | 200,000[6] | 1,032[6] |
| F12[3] | M0[6] | 5.864 | 3,900[6] | −10.70 | 190,000[6] | 955[6] |
| F13 | M3 / K2[6] | 5.957 | 4,200[6] | −11.39 | 290,000[6] | 1,017[6] |
| F14 | M3 / M1[6] | 6.167 | 3,700[6] | −10.25 | 74,000[6][2] | 662[6] |
| F15 | G0 / G6[6] | 6.682 | 6,850[2] | −10.07 | 229,000[2]–620,000[6] | 340[2] |
RSGC1-F01 is ared supergiant with a radius calculated to be between 1,450[7] and 1,530[6] times that of theSun (R☉) (the radius is calculated by applying theStefan-Boltzmann law), making it one of thelargest stars discovered so far. This corresponds to a volume 3.58 billion times bigger than the Sun. If placed at the center of theSolar System, thephotosphere would engulf the orbit ofJupiter.
RSGC1-F02 is a red supergiant with a radius calculated to be between 1,499[2] and 1,549[5] or 1,128[6] R☉ (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 is a peculiar red supergiant that 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 be4.2×10−5 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 withVY Canis Majoris as a similarly extreme red supergiant, both displaying stronger and possibly eruptive mass loss.[7]
| Bound | |
|---|---|
| Unbound | |
| Visual grouping | |
