NGC 1605

NGC 1605
Pan-STARRS image of NGC 1605
Observation data (J2000 epoch)
Right ascension04h 34m 58.4s
Declination+45° 16′ 09″
Distance7,990 ± 320 ly (2,449 ± 98 pc)
Apparent magnitude (V)11.0
Apparent dimensions (V)5.0′ × 5.0′
Physical characteristics
Mass623 M☉
Estimated age400±50 Myr
Associations
ConstellationPerseus
See also: Open cluster, List of open clusters

NGC 1605 is an open cluster of stars in the northern constellation of Perseus. It was discovered by German-British astronomer William Herschel on December 11, 1786. This cluster is located at a distance of approximately 8,000 ly (2,449 pc) from the Sun. It spans an angular size of 5.0′ × 5.0′ with an apparent visual magnitude of 11.0.

Observations

This cluster has a low concentration with a Trumpler class of III 2 m. It is estimated to have 623 times the mass of the Sun with a core radius of 2.49+0.27
−0.41 pc. The cluster is drifting closer to the Sun with a line of sight velocity component of −15.27±1.35 km/s. It is a member of the young thin disk population of the Milky Way.

In 2021, D. Camargo presented results that suggested NGC 1605 is actually a binary open cluster system. The data showed two distinct stellar populations in the region: NGC 1605a with an age of 600 Myr and NGC 1605b at an age of 2 Gyr. This large age difference seemed to indicate a close encounter between two clusters that resulted in tidal capture. The presence of possible tidal debris appeared to support this hypothesis. However, a 2022 study of Gaia 3 data contradicted this finding, suggesting the apparent difference was the result of contamination by field stars.

The open cluster Can Batlló 1 may be located less than 330 light-years (100 pc) from NGC 1605.

References

  1. 1 2 Gaia Collaboration; et al. (June 2023), "Gaia Data Release 3. Mapping the asymmetric disc of the Milky Way", Astronomy & Astrophysics, 674, id. A37, arXiv:2206.06207, Bibcode:2023A&A...674A..37G, doi:10.1051/0004-6361/202243797.
  2. 1 2 3 Almeida, Duarte; et al. (January 2025), "Open cluster dissolution rate and the initial cluster mass function in the solar neighbourhood: Modelling the age and mass distributions of clusters observed by Gaia", Astronomy & Astrophysics, 693, id. A305, arXiv:2412.19204, Bibcode:2025A&A...693A.305A, doi:10.1051/0004-6361/202451853.
  3. 1 2 3 Collinder, Per (1931), "On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of Open Galactic Clusters", Annals of the Observatory of Lund, 2: B1–B46, Bibcode:1931AnLun...2....1C. See p. B5.
  4. 1 2 3 4 Gokmen, Sevinc; et al. (December 2023), "CCD UBV and Gaia DR3 Analyses of the Open Clusters King 6 and NGC 1605", The Astronomical Journal, 166 (6), id. 263, arXiv:2311.00054, Bibcode:2023AJ....166..263G, doi:10.3847/1538-3881/ad08b0.
  5. ↑ Seligman, C., "NGC Objects: NGC 1600 - 1649", Celestial Atlas, retrieved 2026-03-25.
  6. ↑ Prostak, Sergio (October 18, 2021), "Astronomer Discovers Ancient Binary Open Cluster in Milky Way", Sci.News, retrieved 2026-03-26.
  7. ↑ Fang, C. (February 1970), "The estimates of the galactic clusters NGC 1664 and NGC 1605", Astronomy and Astrophysics, 4: 75–77, Bibcode:1970A&A.....4...75F.
  8. ↑ Camargo, Denilso (December 2021), "NGC 1605a and NGC 1605b: An Old Binary Open Cluster in the Galaxy", The Astrophysical Journal, 923 (1), id. 21, arXiv:2109.14664, Bibcode:2021ApJ...923...21C, doi:10.3847/1538-4357/ac2835.
  9. 1 2 Anders, Friedrich; et al. (March 2022), "NGC 1605 is not a Binary Cluster", Research Notes of the AAS, 6 (3), id. 58, arXiv:2203.08153, Bibcode:2022RNAAS...6...58A, doi:10.3847/2515-5172/ac6034.
  10. ↑ Anders, Friedrich; et al. (July 2022), "Binary star clusters - do they really exist? The case of NGC 1605", EAS2022, European Astronomical Society Annual Meeting, held 27 June-1 July 2022 in Valencia, Spain. EAS2022, Session SS15 : The Renaissance of Open Cluster Science with Gaia, ePoster, id. 1857, Bibcode:2022eas..conf.1857A.