NGC 6624
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Key facts
- Class
- VI
- Constellation
- Sagittarius
- Right ascension
- 18 23 41
- Declination
- − 30 ° 21 ′ 39 ″
- Distance
- 25.8 ± 1.1 kly (7.91 ± 0.34 kpc )
- Apparent dimensions v
- 8.8 arcminutes
- Metallicity
- [ Fe/H ] = −0.56 ± 0.27 dex
- Other designations
- ESO 457-11, GCl 93, CD −30 15631 , CPD −30 5486 , HD 168943
via Wikipedia infobox
Wikidata facts
- Instance of
- star
- Part of
- Milky Way
- Constellation
- Sagittarius
- Distance from Earth
- 0.008
- Image
- NGC 6624 HST 10573 R814G606B435.png
Show 13 more facts
- metallicity
- -0.63
- absolute magnitude
- -7.45
- epoch
- J2000.0
- Commons category
- NGC 6624
- discoverer or inventor
- William Herschel
- apparent magnitude
- 7.009
- time of discovery or invention
- 1784-06-24
- catalog code
- [KPS2012] MWSC 2906
- right ascension
- 275.918792
- declination
- -30.361028
- radial velocity
- 69.0
- right ascension component of proper motion
- -1.29
- declination component of proper motion
- -9.77
Sources (2)
via Wikidata · CC0
~2 min read
Encyclopedic overview
The 4U 1820-30 system, consisting of a neutron star and a white dwarf, compared to the Earth and the Sun (bottom). The neutron star is tied with PSR J1748−2446ad as the fastest rotating pulsar known, both making 716 revolutions per second. NGC 6624 is a globular cluster in the constellation Sagittarius. It was discovered on 24 June 1784 by the astronomer William Herschel. It is given an apparent magnitude of 7.6 to 8.5. Six pulsars are known in NGC 6624. The first of these to be discovered was PSR J1823-3021A. This globular cluster also contains 4U 1820-30, a low-mass X-ray binary with an orbital period of only 11.5 minutes, consisting of a neutron star and a white dwarf. Astronomers using the NICER instrument have found evidence that the neutron star is spinning at 716 Hz (times per second), or 42,960 revolutions per minute, the same velocity as the fastest known spinning neutron star PSR J1748−2446ad and the only one in such a system.
NGC 6624 is visible as a hazy spot with a small telescope, and appears as a star-like object with binoculars. Its core appears significantly condensed. It is located 0.8 degrees southeast of the star Delta Sagittarii, and is about 1.17 kpc (3.8 kly) from the Galactic Center.
Excerpted from Wikipedia’s “NGC 6624” article, available under the CC BY-SA 4.0 licence.