Stephenson 2 DFK 52
ALMA image of Stephenson 2 DFK 52 and its sorrounding dust and gas cloud Credit: ALMA(ESO/NAOJ/NRAO)/M. Siebert et al. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Scutum |
| Right ascension | 18h 39m 23.4s[1] |
| Declination | −06° 02′ 16″[1] |
| Apparent magnitude (V) | 17.6[2] |
| Characteristics | |
| Evolutionary stage | Red supergiant[3] |
| Spectral type | M0I[3] |
| Apparent magnitude (J) | 11.27[2] |
| Apparent magnitude (H) | 8.76[2] |
| Apparent magnitude (K) | 7.42[2] |
| Astrometry | |
| Distance | 4,900[4] ly |
| Details | |
| Radius | 335[4] – 357[5] R☉ |
| Luminosity | 20,900[4] – 24,000[5] L☉ |
| Temperature | 3,790[4] – 3,800[5] K |
| Other designations | |
| Stephenson 2 DFK 52, TIC 328138534, 2MASS J18392341-0602158[6] | |
| Database references | |
| SIMBAD | data |
Stephenson 2 DFK 52 is a red supergiant star located in the open cluster Stephenson 2 in the constellation Scutum at a distance of about 4,900 light-years from Earth.[1] The star gained attention in 2025 following Atacama Large Millimeter/submillimeter Array (ALMA) observations that revealed a large circumstellar outflow of dust and gas, the largest known circumstellar outflow around any red supergiant star.[3]
Observation history
The open cluster Stephenson 2 was discovered by American astronomer Charles Bruce Stephenson in 1990 in the data obtained by a deep infrared survey.[1][7] The cluster is also known as RSGC2, one of several massive open clusters in Scutum, each containing multiple red supergiants.[8] The 52nd brightest star in the K band was given an identifier number of 52.[1]
Circumstellar environment
ALMA observations in 2023–2024 revealed that Stephenson 2 DFK 52 is surrounded by a large dust and gas outflow extending up to 50,000 AU in radius (or approximately 0.8 light-years).[3] If the star was located at the distance Betelgeuse is from our Solar System, this circumstellar cocoon would appear roughly one-third the angular width of the full moon.[9]
This suggests that the star went through a dramatic mass-loss event ~4,000 years ago, resulting in the incredibly large dust envelope.[3] Estimates suggest the total mass loss to the extended circumstellar material at 0.1–1 M☉.[3] The scale and asymmetry of the mass ejection cannot be easily explained by radiation pressure alone, suggesting possible additional mechanisms such as a short-lived superwind phase or multiple star interactions and the star is a progenitor for a Type II-P supernova explosion.[3]
See also
References
- ^ a b c d e Davies, Ben; Figer, Don F.; Kudritzki, Rolf-Peter; MacKenty, John; Najarro, Francisco; Herrero, Artemio (2007-09-25). "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.
- ^ a b c d Zacharias, N.; Monet, D. G.; Levine, S. E.; Urban, S. E.; Gaume, R.; Wycoff, G. L. (2004). "The Naval Observatory Merged Astrometric Dataset (NOMAD)". American Astronomical Society Meeting Abstracts. 205. Bibcode:2004AAS...205.4815Z.
- ^ a b c d e f g Siebert, M. A.; Beck, E. De; Quintana-Lacaci, G.; Vlemmings, W. H. T. (2025-08-01). "Stephenson 2 DFK 52: Discovery of an exotic red supergiant in the massive stellar cluster RSGC2". Astronomy & Astrophysics. 700: L11. arXiv:2507.11609. Bibcode:2025A&A...700L..11S. doi:10.1051/0004-6361/202555975. ISSN 0004-6361.
- ^ a b c d Davies, Ben; Figer, Don F.; Kudritzki, Rolf-Peter; MacKenty, John; Najarro, Francisco; Herrero, Artemio (2007-09-25). "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.
- ^ a b c Humphreys, Roberta M.; Helmel, Greta; Jones, Terry J.; Gordon, Michael S. (2020-08-03). "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.
- ^ "Simbad - Object view". simbad.cds.unistra.fr. Retrieved 2025-12-17.
- ^ Stephenson, C. B. (1990). "A possible new and very remote galactic cluster". The Astronomical Journal. 99: 1867. Bibcode:1990AJ.....99.1867S. doi:10.1086/115464.
- ^ Negueruela, I.; González-Fernández, C.; Marco, A.; Clark, J. S.; Martínez-Núñez, S. (2010). "Another cluster of red supergiants close to RSGC1". Astronomy and Astrophysics. 513: A74. arXiv:1002.1823. Bibcode:2010A&A...513A..74N. doi:10.1051/0004-6361/200913373. S2CID 118531372.
- ^ [email protected]. "A unique supergiant star". www.eso.org. Retrieved 2026-04-06.