Messier 4

Messier 4
Globular star cluster Messier 4
Observation data (J2000 epoch)
ClassIX[1]
ConstellationScorpius
Right ascension16h 23m 35.22s[2]
Declination−26° 31′ 32.7″[2]
Distance6.033 kly (1.850 kpc)[3]
Apparent magnitude (V)5.6[4]
Apparent dimensions (V)26′.0
Physical characteristics
Mass8.4×104[5] M☉
Radius35 light-years [citation needed]
Metallicity = −1.07[6] dex
Estimated age(12.2 ± 0.2) Gyr[7]
Notable featuresClosest globular cluster
Other designationsNGC 6121[8]
See also: Globular cluster, List of globular clusters

Messier 4 or M4 (also known as NGC 6121 or the Spider Globular Cluster) is a globular cluster in the constellation of Scorpius. It was discovered by Philippe Loys de Chéseaux in 1745 and catalogued by Charles Messier in 1764.[9] It was the first globular cluster in which individual stars were resolved.[9]

  1. ^ Cite error: The named reference hcob849_11 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference aj140_6_1830 was invoked but never defined (see the help page).
  3. ^ Baumgardt, H.; et al. (2021). "Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST, and literature data". Monthly Notices of the Royal Astronomical Society. 505 (4): 5957–5977. arXiv:2105.09526. Bibcode:2021MNRAS.505.5957B. doi:10.1093/mnras/stab1474.
  4. ^ "Messier 4". SEDS Messier Catalog. Retrieved 21 July 2024.
  5. ^ Vitral, E.; et al. (2023). "An elusive dark central mass in the globular cluster M4". Monthly Notices of the Royal Astronomical Society. 522 (4): 5740–5757. arXiv:2305.12702. Bibcode:2023MNRAS.522.5740V. doi:10.1093/mnras/stad1068.
  6. ^ Cite error: The named reference aaa490_2 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference aaa143_1 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference simbad was invoked but never defined (see the help page).
  9. ^ a b "Messier Object 4". www.messier.seds.org. Retrieved 2023-11-13.