Wikipedia

NGC 7789

NGC 7789
NGC 7789 taken with an amateur telescope
Observation data (J2000.0 epoch)
Right ascension23h 57m 24s[1]
Declination+56° 42′ 30″[1]
Distance7.6 kly (2,337[2])
Apparent magnitude (V)6.7
Apparent dimensions (V)16′[2]
Physical characteristics
Mass6620.4±762.5[3] M☉
Estimated age1.4-1.7 GYr[2]
Other designationsCaroline's Rose,[4] White Rose Cluster, Cr 460, Mel 245
Associations
ConstellationCassiopeia
See also: Open cluster, List of open clusters

NGC 7789 (also known as Caroline's Rose,[4] Caroline's Haystack,[5] or the White Rose Cluster) is an open cluster located around 7,600 light years from Earth in the constellation of Cassiopeia. It is intermediate-age cluster with estimates ranging from 1.4 to 1.7 billion years old. It has a mass of around 6,620.4±762.5 solar masses.[3]

It was discovered by Caroline Herschel in 1783. Her brother William Herschel included it in his catalog as H VI.30. This cluster is also known as the "White Rose" Cluster or "Caroline's Rose" Cluster because when seen visually, the loops of stars and dark lanes look like the swirling pattern of rose petals as seen from above.

Map showing location of NGC 7789 in Cassiopeia

Characteristics

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Age

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While it is known that the cluster is of intermediate-age, its exact age is known with studies giving estimates ranging from 1.4 to 1.6[6]-1.7 billion years.[3] The wide range of ages and little consensus on the age of NGC 7788 is from the combined effects of differential reddening, high binary fraction and rotation-driven broadening of main-sequence turnoff.[7]

Abundances

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The abundances of this cluster is not simple but is instead complex with various elements having raised abundances. Elements that are formed through neutron-capture are significantly enhanced in their abundance, particularly barium which has an abundance of [Ba/Fe] +0.47 to +0.48. Elements that are produced by the r-process and s-process on the other hand such as iron and yttrium are not as abundant.[8][7] There seems to be some minor discrepancies for elements such as calcium, sodium, oxygen and aluminum (only one doublet).[9]

Early studies that estimated the photometric metallicity of NGC 7789 placed the cluster as having sub-solar values ([Fe/H] −0.26±0.10). However modern studies have placed the iron abundance to be similar to the Sun at [Fe/H] −0.04±0.05.[10] The nitrogen abundance of stars within NGC 7789 are enhanced compared to the rest of the galaxy. Giant stars in the cluster have a abundance of [N/Fe] 0.15±0.13 while clump stars have a abundance of [N/Fe] 0.26±0.08. Ratios of sodium and aluminum are also enhanced.[7]

Lithium

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The majority of red giant stars within the cluster have abundances of light elements such as lithium, carbon, nitrogen and oxygen that are consistent. However the stars NGC 7789-193 and NGC 7789-301 have anomalously high abundances of lithium with the latter also having strong helium features. There are two explanations for this abundance, the first is internal mixing of the star during their helium-flash while the second is interactions with a companion star sometime in the past. Either explanation involves the synthesis of lithium through the Cameron-Fowler Berillyum transport mechanism.[8][11][12][7]

Content

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NGC 7789 has a rich and dense stellar population. It has a large number of main-sequence stars (yellow dwarfs), a prominent red giant population and an unusually large population of blue stragglers.[8][13]

References

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  1. ^ a b Xin, Y; Deng, L (2005). "Blue Stragglers in Galactic Open Clusters and Integrated Spectral Energy Distributions". The Astrophysical Journal. 619 (2): 824–838. arXiv:astro-ph/0410325. Bibcode:2005ApJ...619..824X. doi:10.1086/426681. S2CID 2087723.
  2. ^ a b c Kharchenko, N. V; Piskunov, A. E; Röser, S; Schilbach, E; Scholz, R.-D (2005). "Astrophysical parameters of Galactic open clusters". Astronomy and Astrophysics. 438 (3): 1163–1173. arXiv:astro-ph/0501674. Bibcode:2005A&A...438.1163K. doi:10.1051/0004-6361:20042523. S2CID 9079873.
  3. ^ a b c Wu, Zhen-Yu; Du, Cui-Hua; Ma, Jun; Zhou, Xu (2009). "Mass of Open Cluster NGC 7789". Chinese Physics Letters. 26 (2) 029701. Bibcode:2009ChPhL..26b9701W. doi:10.1088/0256-307X/26/2/029701. S2CID 250826535.
  4. ^ a b "Caroline's Rose (NGC 7789)". Sky & Telescope. Retrieved 23 June 2020.
  5. ^ Stoyan, Ronald; Schurig, Stephan (2014). interstellarum Deep Sky Atlas. Erlangen: Cambridge University Press; Oculum-Verlag GmbH. ISBN 978-1-107-50338-0. OCLC 920437579.
  6. ^ Gim, Munhwan; Hesser, James E.; McClure, Robert D.; Stetson, Peter B. (1998-10). "The Open Cluster NGC 7789. I. Radial Velocities for Giant Stars". Publications of the Astronomical Society of the Pacific. 110 (752): 1172–1182. doi:10.1086/316241. ISSN 0004-6280. {{cite journal}}: Check date values in: |date= (help)
  7. ^ a b c d Kadri Yakut, Belinda Kalomeni, Saul Rappaport, A binary-based reassessment of the age and stellar properties of NGC 7789 using 12 binary components, Monthly Notices of the Royal Astronomical Society, Volume 546, Issue 4, March 2026, stag172, https://doi.org/10.1093/mnras/stag172
  8. ^ a b c Tautvaišienė, G.; Edvardsson, B.; Puzeras, E.; Ilyin, I. (1 March 2005). "Chemical composition of evolved stars in the open cluster NGC 7789". Astronomy & Astrophysics. 431 (3): 933–942. doi:10.1051/0004-6361:20041935. ISSN 0004-6361.
  9. ^ Pancino, E.; Carrera, R.; Rossetti, E.; Gallart, C. (1 February 2010). "Chemical abundance analysis of the open clusters Cr 110, NGC 2099 (M 37), NGC 2420, NGC 7789, and M 67 (NGC 2682)". Astronomy & Astrophysics. 511: A56. doi:10.1051/0004-6361/200912965. ISSN 0004-6361.
  10. ^ Tautvaišienė, G.; Edvardsson, B.; Puzeras, E.; Ilyin, I. (1 March 2005). "Chemical composition of evolved stars in the open cluster NGC 7789". Astronomy & Astrophysics. 431 (3): 933–942. doi:10.1051/0004-6361:20041935. ISSN 0004-6361.
  11. ^ Nagarajan, Neel; Sneden, Christopher; Afsar, Melike; Pilachowski, Catherine A. (14 April 2023), "Chemical Compositions of Red Giant Stars in the Old Open Cluster NGC 7789", The Astronomical Journal, 165 (6): 245, arXiv:2304.07359, doi:10.3847/1538-3881/accdda
  12. ^ Anthony-Twarog, Barbara J.; Brunker, Samantha W.; Deliyannis, Constantine P.; Rich, Evan; Steinhauer, Aaron; Sun, Qinghui; Twarog, Bruce A. (29 October 2025), WOCS XCIII: NGC 7789: the Evolution of Li, Stellar Rotation, and Extended Main Sequence Turnoffs, arXiv:2510.25862
  13. ^ Koroleva, L. S. (1975-04). "The open cluster NGC 7789". Soviet Astronomy. 18: 584. ISSN 0038-5301. {{cite journal}}: Check date values in: |date= (help)
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  • Media related to NGC 7789 at Wikimedia Commons
  • NGC 7789 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
  • SEDS – NGC 7789