NGC 7790

NGC 7790
NGC 7790 (taken from Stellarium)
Credit: Roberto Mura
Observation data (J2000.0 epoch)
Right ascension23h 58m 24.2s
Declination+61° 12′ 30″
Distance10.76 ± 0.75 kly (3.30 ± 0.23 kpc)
Apparent magnitude (V)8.5
Apparent dimensions (V)7′.4 diameter
Physical characteristics
Estimated age60–80 Myr
Other designationsCr 461
Associations
ConstellationCassiopeia
See also: Open cluster, List of open clusters

NGC 7790, also known as the Widow's Web Cluster, is a young open cluster of stars located some 10,800 light years away from Earth in the northern constellation of Cassiopeia. At this distance, the light from the cluster has undergone extinction from interstellar gas and dust equal to E(B – V ) = 0.51 magnitude in the UBV photometric system. NGC 7790 has a Trumpler class rating of II2m and the estimated age is 60–80 million years. It contains three cepheid variables: CEa Cas, CEb Cas, and CF Cas.

This cluster is on an orbit through the Milky Way galaxy that has an eccentricity of 0.22 ± 0.07 and a period of (225.0 ± 27.1) million years. It will come as close as 20.2 ± 3.9 kly (6.2 ± 1.2 kpc) to, and as distant as 31.6 ± 2.9 kly (9.7 ± 0.9 kpc) from, the Galactic Center. The maximum distance reached above (or below) the galactic plane is 0.78 ± 1.30 kly (0.24 ± 0.40 kpc). On average, it will cross the galactic plane every (35.7 ± 13.0) million years.

A recent study proposed that NGC 7790 and the neighboring cluster Berkeley 58 could form a binary open cluster, a conclusion supported by their consistent astrometric solutions, evolutionary ages, and radial velocities. Four classical Cepheid variables (CE Cas A, CE Cas B, CF Cas, and CG Cas) were identified as possible members of the binary cluster.

References

  1. 1 2 3 Revised New General Catalogue and Index Catalogue, olfgang Steinicke, February 2009, retrieved 2013-07-01.[permanent dead link]
  2. 1 2 3 4 5 Gupta, A. C.; et al. (September 2000), "A complete photometric study of the open cluster NGC 7790 containing Cepheid variables", Astronomy and Astrophysics Supplement, 145 (3): 365–375, Bibcode:2000A&AS..145..365G, doi:10.1051/aas:2000247.
  3. 1 2 Davidge, T. J. (December 2012), "The Young Open Clusters King 12, NGC 7788, and NGC 7790: Pre-main-sequence Stars and Extended Stellar Halos", The Astrophysical Journal, 761 (2): 155, arXiv:1211.6398, Bibcode:2012ApJ...761..155D, doi:10.1088/0004-637X/761/2/155, S2CID 119205384.
  4. ↑ O'Meara, Stephen James (2011). Deep-Sky Companions: The Secret Deep. Cambridge University Press. ISBN 978-0-521-19876-9.
  5. ↑ Wu, Zhen-Yu; et al. (November 2009), "The orbits of open clusters in the Galaxy", Monthly Notices of the Royal Astronomical Society, 399 (4): 2146–2164, arXiv:0909.3737, Bibcode:2009MNRAS.399.2146W, doi:10.1111/j.1365-2966.2009.15416.x, S2CID 6066790.
  6. 1 2 Majaess, Daniel; Turner, David G. (June 2024). "A Suite of Classical Cepheids Tied to the Binary Cluster Berkeley 58 and NGC 7790". Publications of the Astronomical Society of the Pacific. 136 (1060): 064201. Bibcode:2024PASP..136f4201M. doi:10.1088/1538-3873/ad59c6.
Map showing location of NGC 7790 (Roberto Mura)