NGC 3201 (also known as Caldwell 79) is a low galactic latitude
globular cluster in the southern
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
of
Vela. It has a very low central concentration of stars.
This cluster was discovered by
James Dunlop on May 28, 1826 and listed in his 1827 catalogue. He described it as "a pretty large pretty bright round nebula, 4′ or 5′ diameter, very gradually condensed towards the centre, easily resolved into stars; the figure is rather irregular, and the stars are considerably scattered on the south".
[
The ]radial velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...
of this cluster is unusually high at 490 km/s, larger than any other cluster known. This corresponds to a peculiar velocity
Peculiar motion or peculiar velocity refers to the velocity of an object relative to a ''rest frame'' — usually a frame in which the average velocity of some objects is zero.
Galactic astronomy
In galactic astronomy, peculiar motion refers to ...
of 240 km/s. While high, this is lower than the escape velocity of the Milky Way galaxy.[ It is located at a distance of 16,300 ]light year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s from the Sun and has an estimated 157,000 times the mass of the Sun
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...
.[ This cluster is about 10.24 billion years old.][
The stellar population of this cluster is inhomogeneous, varying with distance from the core. The ]effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
of the stars shows an increase with greater distance, with the redder and cooler stars tending to be located closer to the core. As of 2010, this is one of only two clusters (including Messier 4) that shows a definite inhomogeneous population.[
]
Black holes
Because NGC 3201 is a less dense globular cluster, far from undergoing core collapse, it is believed to harbor a substantial black hole
A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...
population in its core.
Indeed, a few black holes have been detected in this cluster, orbiting nearby stars.
In a study from 2022,
Gallery
Caldwell 79.jpg, Astronomers discovered a black hole at the heart of NGC 3201.
Artist’s impression of the black hole binary system in NGC 3201.jpg, Artist's impression of the black hole binary system in NGC 3201.
See also
* List of nearest black holes
This is a list of known black holes that are close to the Solar System, which Earth is part of.
It is thought that most black holes are solitary, but black holes in binary or larger systems are much easier to detect. Solitary black holes can gene ...
References
External links
Globular Cluster NGC 3201 at SEDS pages
*
NGC 3201
at ''DOCdb'' (Deep Sky Observer's Companion)
{{DEFAULTSORT:NGC 3201
Globular clusters
Vela (constellation)
3201
079b
18260501