Palomar 5

Palomar 5
Palomar 5
Observation data (J2000 epoch)
Class	XII
Constellation	Serpens
Right ascension	15h 16m 05.3s
Declination	–00° 06′ 41″
Distance	76 kly (23 kpc)
Apparent magnitude (V)	+11.75
Apparent dimensions (V)	6.9′
Physical characteristics
Mass	3.00×104 M☉
Radius	76 ly
Estimated age	11.5±1.0 Gyr
Notable features	Erroneously thought to be a dwarf galaxy
Other designations	UGC 9792, GCl 32
	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]

References

^ ^a ^b ^c "SIMBAD Astronomical Database". Results for Palomar 5. Retrieved 2006-11-17.
^ Hessels, J. W. T.; et al. (November 2007), "A 1.4 GHz Arecibo Survey for Pulsars in Globular Clusters", The Astrophysical Journal, 670 (1): 363–378, arXiv:0707.1602, Bibcode:2007ApJ...670..363H, doi:10.1086/521780, S2CID 16914232.
^ Boyles, J.; et al. (November 2011), "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, S2CID 118649860.
^ distance × sin( diameter_angle / 2 ) = 76 ly. radius
^ 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.
^ 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.
^ Chen, C. W.; Chen, W. P. (October 2010), "Morphological Distortion of Galactic Globular Clusters", The Astrophysical Journal, 721 (2): 1790–1819, Bibcode:2010ApJ...721.1790C, doi:10.1088/0004-637X/721/2/1790