NGC 6712

NGC 6712
NGC 6712, by HST
Observation data (J2000 epoch)
Class	IX:[1]
Constellation	Scutum
Right ascension	18h 53m 04.32s[2]
Declination	–08° 42′ 21.5″[2]
Distance	26.4 kly (8.1 kpc)<[3]
Apparent magnitude (V)	+8.69[2]
Apparent dimensions (V)	7.2'
Physical characteristics
Mass	9.4×104[4] M☉
Metallicity	${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = –0.94[5] dex
Estimated age	10.4 Gyr[5]
Other designations	GCl 103,[2] GC 4441
See also: Globular cluster, List of globular clusters

NGC 6712 is a globular cluster that was probably discovered by Le Gentil on July 9, 1749 when investigating the Milky Way star cloud in Aquila. He described it as a "true nebula," in contrast to the open star cluster M11. Independently discovered by William Herschel on June 16, 1784 and cataloged as H I.47; he also first classified it as a round nebula. John Herschel was the first to describe it as a globular star cluster during his observations in the 1830s. The cluster appears to be about 12 billion years old and may have originally have been significantly more massive having undergone significant mass loss due to passes through the galactic disc.^[3] For a globular cluster, NGC 6712 is somewhat metal-rich.^[6]

NGC 6712 is home to a "black widow" pulsar named PSR J1853−0842A. Such systems involve an extremely rapidly rotating pulsar, accompanied by a low-mass star or brown dwarf. The high amounts of radiation emitted from the pulsar contributes to the evaporation of the low-mass companion, which has a mass between 0.018 and 0.036 solar masses. Although pulsars rotate more slowly with age, PSR J1853−0842A is accelerating, which would not be possible without it being within a globular cluster.^[6]