It is about 29,400[4]light years away from
Earth and around 6,500 light-years[11] from the
Galactic Center. It is roughly the same size and
luminosity as its neighbour in space,
M69.[12] M70 has a very small core radius of 0.22 ly (0.068 pc)[13] and a half-light radius of 182.0 ly (55.80 pc).[14] This cluster has undergone
core collapse, leaving it centrally concentrated[15] with the luminosity distribution following a
power law.[11]
There are two distinct stellar populations in the cluster, with each displaying unique abundance abundances. These likely represent different generations of stars.[16] Five known
variable stars lie within the broadest radius, the tidal radius, of it, all of which are
RR Lyrae variables.[8][17] The cluster may have two
blue stragglers near the core.[11]
Gallery
Image by Hubble Space Telescope
Map showing M70, against a conventional (southern) horizon
^Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14,
Bibcode:
1927BHarO.849...11S.
^
abLiller, M. H. (October 1983), "The variable stars in the field of the globular cluster NGC 6681", Astronomical Journal, 88: 1463–1469,
Bibcode:
1983AJ.....88.1463L,
doi:
10.1086/113435.
^Frommert, Hartmut; Kronberg, Christine (30 August 2007),
"Globular Cluster M70", SEDS Messier pages, Students for the Exploration and Development of Space (SEDS), retrieved 4 December 2018.
^Djorgovski, S. (January 1993), "Physical Parameters of Galactic Globular Clusters", in Djorgovski, S. G.; Meylan, G. (eds.), Structure and Dynamics of Globular Clusters. Proceedings of a Workshop held in Berkeley, California, July 15–17, 1992, to Honor the 65th Birthday of Ivan King, vol. 50, San Francisco, California: Astronomical Society of the Pacific, p. 373,
Bibcode:
1993ASPC...50..373D,
ISBN978-0937707692.
^On the southernmost line of the main (teapot) asterism; its declination means it will not rise (above the horizon) above the
58th parallel north and will need the observer to be as much as
a further fifteen degrees of latitude south for detailed, little distorted observation