NGC 1857
| NGC 1857 | |
|---|---|
 Pan-STARRS image of NGC 1857 | |
| Observation data (J2000 epoch) | |
| Right ascension | 05h 20m 07.4s[1] |
| Declination | +39° 20′ 10″[1] |
| Distance | 9,057 ly (2,777.0 pc)[1] |
| Apparent magnitude (V) | 7.0[2] |
| Apparent dimensions (V) | 7′[2] |
| Physical characteristics | |
| Estimated age | 257 Ma[1] |
| Other designations | C 0411+511, OCl 397.0, NGC 1857[3] |
| Associations | |
| Constellation | Auriga[2] |
NGC 1857 is an open cluster of stars in the northern constellation of Auriga,[2] less than a degree to the south of the naked eye star Lambda Aurigae.[4] It was discovered by German-English astronomer William Herschel on September 30, 1780.[5] This cluster has an apparent visual magnitude of 7.0 and spans an angular size of 7′ on the sky.[2] NGC 1857 lies at an estimated distance of 9,057 light-years (2,777 pc) from the Sun,[1] toward the galactic anticenter.[6][7]
NGC 1857 has 360±100[8] member stars and an estimated age of 257 million years.[1] In the Trumpler classification system, it is rated as 'II 2 r'. This indicates it is somewhat disparate (II), of moderate brightness (2), and is rich in stars (r).[9] The abundance of elements more massive than helium, the cluster's metallicity, is nearly the same as in the Sun.[8]
The core radius of NGC 1857 is 3.41+1.41
−1.23 pc, while it has a King radius of 12.52+52.30
−6.78 pc. The estimated mass within the latter radius is 586.1±17.9 M☉.[10] The irregular morphology of NGC 1857 suggests it has two dense core regions rather than just one.[11] NGC 1857 has a small angular separation from another open cluster, Czernik 20. However, this is most likely a chance alignment.[12][11]
References
[edit]- 1 2 3 4 5 6 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.
- 1 2 3 4 5 Finlay, Warren H. (2014), Concise Catalogue of Deep-Sky Objects, The Patrick Moore Practical Astronomy Series (2nd ed.), Springer Cham, p. 181, doi:10.1007/978-3-319-03170-5, ISBN 978-3-319-03169-9.
- ↑ "NGC 1528", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2026-08-10.
- ↑ Streicher, Magda (December 2015), "Sky delights: Auriga the Coach-driver", MNASSA, 74 (12): 305–310, Bibcode:2015MNSSA..74..305S.
- ↑ Hoskin, Michael A.; Steinicke, Wolfgang (2012), The Construction of the Heavens: William Herschel's Cosmology, Cambridge University Press, p. 38, ISBN 978-1-107-01838-9.
- ↑ Colegrove, T.; et al. (December 1994), "CCD Photometry of the Open Cluster NGC 1857", Bulletin of the American Astronomical Society, American Astronomical Society, 185th AAS Meeting, 26: 1486, Bibcode:1994AAS...18510304C.
- ↑ Camargo, D.; et al. (July 2013), "Towards a census of the Galactic anticentre star clusters - III. Tracing the spiral structure in the outer disc", Monthly Notices of the Royal Astronomical Society, 432 (4): 3349–3360, Bibcode:2013MNRAS.432.3349C, doi:10.1093/mnras/stt703.
- 1 2 Hoq, Sadia; Clemens, D. P. (October 2015), "Open Clusters as Probes of the Galactic Magnetic Field. I. Cluster Properties", The Astronomical Journal, 150 (4), id. 135, arXiv:1509.06777, Bibcode:2015AJ....150..135H, doi:10.1088/0004-6256/150/4/135.
- ↑ Sujatha, S.; et al. (December 2006), "Mass function of open clusters NGC 1857 and Czernik 25", Bulletin of the Astronomical Society of India, 34 (4): 357, Bibcode:2006BASI...34..357S.
- ↑ Almeida, Duarte; et al. (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 and Astrophysics, 693, arXiv:2412.19204, Bibcode:2025A&A...693A.305A, doi:10.1051/0004-6361/202451853.
- 1 2 Bhattacharya, S.; et al. (January 2017), "Morphology of open clusters NGC 1857 and Czernik 20 using clustering algorithms", Astronomy and Computing, 18: 1–7, arXiv:1611.00117, Bibcode:2017A&C....18....1B, doi:10.1016/j.ascom.2016.10.001.
- ↑ Angelo, M. S.; et al. (March 2022), "Investigating Galactic binary cluster candidates with Gaia EDR3", Monthly Notices of the Royal Astronomical Society, 510 (4): 5695–5724, arXiv:2112.15247, Bibcode:2022MNRAS.510.5695A, doi:10.1093/mnras/stab3807.
