NGC 6652
| NGC 6652 | |
|---|---|
.jpg) NGC 6652 seen by the Hubble Space Telescope | |
| Observation data | |
| Constellation | Sagittarius |
| Right ascension | 18h 35m 45.63s[1] |
| Declination | −32° 59′ 26.6″[1][2] |
| Distance | ~30,000 |
| Apparent magnitude (V) | 9.75 |
| Apparent dimensions (V) | 5.1' x 5.1' |
| Physical characteristics | |
| Estimated age | 13.6 billion years |
| Other designations | NGC 6652, GCl 98, RX J1835.7-3259, 4FGL J1835.7-3258[1] |
NGC 6652 is a globular cluster in Sagittarius. It is located about 6,500 light years from the Galactic Center and about 30,000 light years away from Earth.[3] The cluster was discovered on September 3, 1826 by James Dunlop.[4]
Observations
[edit]According to a study published in 2011 by J. Boyles and his colleagues, the metallicity of the globular cluster NGC 6652 is -0.81 and its mass is 109,000 M☉.[5] In the same study, the distance to the cluster is also estimated at approximately 10.0 kpc (∼32,600 ly). The study published by Forbes and Bridges indicates a metallicity of -0.70.[6]
Stars
[edit]As of November 2022, 267 pulsars had been discovered in 36 globular clusters of the Milky Way.[7] Out of 267 pulsars, two millisecond binary pulsars are located in NGC 6652.[7] The first pulsar in this globular cluster was discovered using the Green Bank Telescope and is known as PSR J1835-3259A. Its period is 3.9 ms[8] and it has an elliptical orbit with eccentricity of 0.95 and a period of 9.25 days. Assuming a mass of 1.4 M☉ the mass of its companion would be 0.74 M☉.[8] The second is PSR J1835−3259B, a millisecond pulsar with a period of 1.83 ms. It is in a nearly circular orbit around a companion with an estimated mass of about 0.2 M☉, probably a white dwarf.[9] This pulsar is probably the source of the gamma radiation from NGC 6652.[10]
Finally, a third candidate was discovered in this cluster based on simultaneous observations from the Chandra X-ray Observatory and the Karl G. Jansky Very Large Array. It was given the name NGC 6652B and is possibly a transitional millisecond pulsar (tMSP), that is, a pulsar that switches between a rotationally powered state and an accretion-powered state.[11] Other hypotheses must also be considered to explain the behavior of NGC 6625B, although less likely than the tMSP. Confirmation that it is indeed a tMSP will come from a direct observation of its state change.[11]
Observations made with the Chandra X-ray Observatory have detected eleven X-ray sources, six of which were already known and five of which are new. Source A is a low-mass X-ray binary (LMXB). Source B suggests the presence of a neutron star in an LMXB system, but with unusual variability.[12] The spectrum of source C suggests it is a cataclysmic variable. The spectrum of source D suggests the presence of a neutron star in an LMXB system, which would make it the third LMXB source of NGC 6652.[12] Finally, sources E and F show spectra located relatively in the hard X-ray region, suggesting the presence of high-energy plasma.[12]
References
[edit]- 1 2 3 "NGC 6652". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-07-06.
- ↑ "NGC 6652 - Globular Cluster in Sagittarius". The Sky Live.
- ↑ Carter, Jamie (13 August 2023). "Space photo of the week: Hubble captures one of our galaxy's oldest objects". Live Science.
- ↑ Segilman, Courtney. "The Celestial Atlas".
- ↑ Boyles, J.; Lorimer, D. R.; Turk, P. J.; Mnatsakanov, R.; Lynch, R. S.; Ransom, S. M.; Freire, P. C.; Belczynski, K. (2011-11-20). "Young Radio Pulsars in Galactic Globular Clusters". The Astrophysical Journal. 742 (1): 51. arXiv:1108.4402. Bibcode:2011ApJ...742...51B. doi:10.1088/0004-637X/742/1/51. ISSN 0004-637X.
- ↑ Forbes, Duncan A.; Bridges, Terry (2010). "Accreted versus in situ Milky Way globular clusters". Monthly Notices of the Royal Astronomical Society. 404 (3): 1203. arXiv:1001.4289. Bibcode:2010MNRAS.404.1203F. doi:10.1111/j.1365-2966.2010.16373.x.
- 1 2 Yin, De-Jiang; Zhang, Li-Yun; Li, Bao-Da; Li, Ming-Hui; Qian, Lei; Pan, Zhichen (2023-05-01). "The Analyses of Globular Cluster Pulsars and Their Detection Efficiency". Research in Astronomy and Astrophysics. 23 (5): 055012. arXiv:2303.09710. Bibcode:2023RAA....23e5012Y. doi:10.1088/1674-4527/acc37e. ISSN 1674-4527.
- 1 2 DeCesar, Megan E.; Ransom, Scott M.; Kaplan, David L.; Ray, Paul S.; Geller, Aaron M. (2015-07-07). "A Highly Eccentric 3.9 Millisecond Binary Pulsar in the Globular Cluster NGC 6652". The Astrophysical Journal. 807 (2): L23. arXiv:1506.03367. Bibcode:2015ApJ...807L..23D. doi:10.1088/2041-8205/807/2/L23. ISSN 2041-8213.
- ↑ Gautam, T.; Ridolfi, A.; Freire, P. C. C.; Wharton, R. S.; Gupta, Y.; Ransom, S. M.; Oswald, L. S.; Kramer, M.; DeCesar, M. E. (2022). "Upgraded GMRT survey for pulsars in globular clusters: I. Discovery of a millisecond binary pulsar in NGC 6652". Astronomy & Astrophysics. 664: A54. arXiv:2205.15274. Bibcode:2022A&A...664A..54G. doi:10.1051/0004-6361/202243062. ISSN 0004-6361.
- ↑ Zhang, Pengfei; Xing, Yi; Wang, Zhongxiang (2022-08-01). "Discovery of γ-Ray Pulsations from PSR J1835–3259B in the Globular Cluster NGC 6652". The Astrophysical Journal Letters. 935 (2): L36. arXiv:2206.13667. Bibcode:2022ApJ...935L..36Z. doi:10.3847/2041-8213/ac88bf. ISSN 2041-8205.
- 1 2 Paduano, Alessandro; Bahramian, Arash; Miller-Jones, James C A; Kawka, Adela; Strader, Jay; Chomiuk, Laura; Heinke, Craig O; Maccarone, Thomas J; Britt, Christopher T; Plotkin, Richard M; Shaw, Aarran W; Shishkovsky, Laura; Tremou, Evangelia; Tudor, Vlad; Sivakoff, Gregory R (2021-07-31). "The MAVERIC Survey: Simultaneous Chandra and VLA observations of the transitional millisecond pulsar candidate NGC 6652B". Monthly Notices of the Royal Astronomical Society. 506 (3): 4107–4120. arXiv:2107.02344. doi:10.1093/mnras/stab1928. ISSN 0035-8711.
- 1 2 3 Stacey, W. S.; Heinke, C. O.; Cohn, H. N.; Lugger, P. M.; Bahramian, A. (2012-05-20). "An Examination of the X-Ray Sources in the Globular Cluster NGC 6652". The Astrophysical Journal. 751 (1): 62. arXiv:1204.0552. Bibcode:2012ApJ...751...62S. doi:10.1088/0004-637X/751/1/62. ISSN 0004-637X.
External links
[edit]
Media related to NGC 6652 at Wikimedia Commons
