Double Cluster

The Double Cluster, is NGC 884 and NGC 869, a group of two open star clusters in the Perseus constellation. It has many blue and red stars.

Both are visible with the naked eye. NGC 869 and NGC 884 lie at a distance of 7,500 light years.^[1] That is relatively close-by (the Milky Way galaxy has a diameter of roughly 100,000 light years.)

Stars

RS Persei and T Persei

These are two red supergiant stars in the star cluster. They are 770 and 510 times larger than the Sun respectively.^[2]

SU Persei and AV Persei

These are also red supergiant stars. They both are 780 and 770 times larger than the Sun respectively.^[3]

S Persei

A red hypergiant 1,212 times larger than the Sun.^[4]

References

↑ Keller, Stefan C.; Grebel, Eva K.; Miller, Grant J.; Yoss, Kenneth M. (2001). "UBVI and Hα photometry of the h and χ Persei cluster". The Astronomical Journal. 122 (1): 248. arXiv:astro-ph/0104179. Bibcode:2001AJ....122..248K. doi:10.1086/321139. S2CID 117819633.
↑ Baron, F.; Monnier, J. D.; Kiss, L. L.; Neilson, H. R.; Zhao, M.; Anderson, M.; Aarnio, A.; Pedretti, E.; Thureau, N.; Ten Brummelaar, T. A.; Ridgway, S. T.; McAlister, H. A.; Sturmann, J.; Sturmann, L.; Turner, N. (2014). "Chara/Mirc Observations of Two M Supergiants in Perseus Ob1: Temperature, Bayesian Modeling, and Compressed Sensing Imaging". The Astrophysical Journal. 785: 46. doi:10.1088/0004-637X/785/1/46. hdl:10023/5302. S2CID 17085548.
↑ Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (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. doi:10.1086/430901. S2CID 15109583.
↑ 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.

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[1] Keller, Stefan C.; Grebel, Eva K.; Miller, Grant J.; Yoss, Kenneth M. (2001). "UBVI and Hα photometry of the h and χ Persei cluster". The Astronomical Journal. 122 (1): 248. arXiv:astro-ph/0104179. Bibcode:2001AJ....122..248K. doi:10.1086/321139. S2CID 117819633.

[2] Baron, F.; Monnier, J. D.; Kiss, L. L.; Neilson, H. R.; Zhao, M.; Anderson, M.; Aarnio, A.; Pedretti, E.; Thureau, N.; Ten Brummelaar, T. A.; Ridgway, S. T.; McAlister, H. A.; Sturmann, J.; Sturmann, L.; Turner, N. (2014). "Chara/Mirc Observations of Two M Supergiants in Perseus Ob1: Temperature, Bayesian Modeling, and Compressed Sensing Imaging". The Astrophysical Journal. 785: 46. doi:10.1088/0004-637X/785/1/46. hdl:10023/5302. S2CID 17085548.

[3] Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (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. doi:10.1086/430901. S2CID 15109583.

[4] 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.

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