NGC 6712 is a
globular cluster that was probably discovered by
Le Gentil on July 9, 1749 when investigating the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...
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.
For a globular cluster, NGC 6712 is somewhat
metal-rich
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...
.
NGC 6712 is home to a "black widow"
pulsar
A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Ea ...
named PSR J1853−0842A. Such systems involve an extremely rapidly rotating pulsar, accompanied by a low-mass star or
brown dwarf
Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...
. 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.
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References
External links
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Simbad
Webda
NGC 6712
{{DEFAULTSORT:NGC 6712
Globular clusters
6712
Scutum (constellation)