IC 361

IC 361, also called Melotte 24 is an open cluster of stars in the constellation Camelopardalis. It was discovered by the British amateur astronomer William F. Denning on February 11, 1893.^[6] This cluster is located at a distance of 10,500 ± 230 light-years from the Sun.^[2] It is very faint with an apparent visual magnitude of 11.7,^[3] requiring a telescope to view. Because of its faintness, this cluster has been poorly studied.^[7] The cluster spans an angular size of 6.0′.^[3]

IC 361
Open star cluster IC 361 in the constellation Camelopardalis
Observation data (J2000 epoch)
Right ascension	04h 18m 56.6s[1]
Declination	+58° 15′ 07″[1]
Distance	10,500 ± 230 ly (3.22 ± 0.07 kpc)[2]
Apparent magnitude (V)	11.7[3]
Apparent dimensions (V)	6.0′[3]
Physical characteristics
Mass	2,459±491[4] M☉
Radius	24.5 ly[2]
Estimated age	759 Myr[1]
Other designations	C 0414+581[5]
Associations
Constellation	Camelopardalis
See also: Open cluster, List of open clusters

This intermediate–age cluster is located in or beyond the Perseus Arm of the Milky Way galaxy.^[7] It is situated near dark nebulae, resulting in significant levels of extinction due to interstellar dust. The cluster has a core radius of 2.0′±0.4′ and a cluster radius of 8.0′±0.5′. At an estimated distance of 3.22 kpc this corresponds to a physical core radius of 6.1 ly and a cluster radius of 24.5 ly.^[2] It has an estimated age of 759 million years.^[1] The cluster is mildly metal deficient, matching the metallicity gradient of the Milky Way.^[7]

Two candidate blue stragglers have been identified in this cluster.^[8]

References

1. Tarricq, Y.; et al. (March 2021), "3D kinematics and age distribution of the open cluster population", Astronomy & Astrophysics, 647, id. A19, arXiv:2012.04017, Bibcode:2021A&A...647A..19T, doi:10.1051/0004-6361/202039388.
2. Joshi, Gireesh C. (March 2022), "A near-infrared and UBVRI photometric analysis of the open cluster IC 361", Indian Journal of Physics, 96 (3): 659–669, arXiv:1901.02948, Bibcode:2022InJPh..96..659J, doi:10.1007/s12648-021-02020-5.
3. Aranda, Ted (2011), 3,000 Deep-Sky Objects, An Annotated Catalogue, Springer New York, p. 122, ISBN 9781441994196.
4. Almeida, Anderson; et al. (October 2023), "Revisiting the mass of open clusters with Gaia data", Monthly Notices of the Royal Astronomical Society, 525 (2): 2315–2340, arXiv:2307.15182, Bibcode:2023MNRAS.525.2315A, doi:10.1093/mnras/stad2291.
5. "IC 361", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2024-06-29.
6. Seligman, Courtney, "IC Objects: IC 350 - 399", Celestial Atlas, retrieved 2024-06-29.
7. Zdanavičius, Justas; et al. (January 2010), "IC 361, a distant intermediate-age cluster in Camelopardalis†", Star clusters: basic galactic building blocks throughout time and space, Proceedings of the International Astronomical Union, IAU Symposium, vol. 266, pp. 557–560, Bibcode:2010IAUS..266..557Z, doi:10.1017/S1743921309992080.
8. Rain, M. J.; et al. (June 2021), "A new, Gaia-based, catalogue of blue straggler stars in open clusters", Astronomy & Astrophysics, 650, id. A67, arXiv:2103.06004, Bibcode:2021A&A...650A..67R, doi:10.1051/0004-6361/202040072.

Further reading

• Zdanavičius, J.; et al. (2010), "Multicolor CCD Photometry of the Open Cluster IC 361", Baltic Astronomy, 19 (1–2): 63–94, Bibcode:2010BaltA..19...63Z, doi:10.1515/astro-2017-0413.
• Piccirillo, J.; Stein, W. L. (August 1978), "Preliminary photometry of the open cluster IC 361.", Astronomical Journal, 83: 971–974, Bibcode:1978AJ.....83..971P, doi:10.1086/112277.
• Shapley, H. (June 1918), "The cluster IC 361", The Observatory, 41: 257, Bibcode:1918Obs....41..257S.