Palomar 5

Palomar 5
Observation data (J2000 epoch)
ClassXII
ConstellationSerpens
Right ascension15h 16m 05.3s[1]
Declination–00° 06′ 41″[1]
Distance76 kly (23 kpc)[2]
Apparent magnitude (V)+11.75
Apparent dimensions (V)6.9′
Physical characteristics
Mass3.00×104[3] M☉
Radius76 ly[4]
Estimated age11.5±1.0 Gyr[5]
Notable featuresErroneously thought to be a dwarf galaxy
Other designationsUGC 9792, GCl 32[1]
See also: Globular cluster, List of globular clusters

Palomar 5 is a globular cluster and a member of the Palomar Globular Clusters group. It was discovered by Walter Baade in 1950, and independently found again by Albert George Wilson in 1955. After the initial name of Serpens, it was subsequently catalogued as Palomar 5.

There is a process of disruption acting on this cluster because of the gravitation of the Milky Way – in fact there are many stars leaving this cluster in the form of a stellar stream. The stream has a mass of 5000 solar masses and is 30,000 light years long.[6] The cluster is currently 60.6 kly (18.6 kpc) from the Galactic Center. It shows a noticeable amount of flattening, with an aspect ratio of 0.62 ± 0.23 between its semimajor axis and semiminor axis.[7]

  1. ^ a b c "SIMBAD Astronomical Database". Results for Palomar 5. Retrieved 2006-11-17.
  2. ^ Cite error: The named reference apj670_1_363 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference apj742_1_51 was invoked but never defined (see the help page).
  4. ^ distance × sin( diameter_angle / 2 ) = 76 ly. radius
  5. ^ Martell, S. L.; Smith, G. H.; Grillmair, C. J. (2002). "A New Age Measurement for Palomar 5". American Astronomical Society, 201st AAS Meeting, #07.11; Bulletin of the American Astronomical Society. 34: 1103. Bibcode:2002AAS...201.0711M.
  6. ^ Ibata, Rodrigo; Gibson, Brad (April 2007). "The Ghosts of Galaxies Past". Scientific American. 296 (4): 40–45. Bibcode:2007SciAm.296d..40I. doi:10.1038/scientificamerican0407-40. ISSN 0036-8733. PMID 17479629.
  7. ^ Cite error: The named reference apj721_2_1790 was invoked but never defined (see the help page).