LEDA 1000714

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LEDA 1000714
PGC 1000714.jpg
Pan-STARRS image of PGC 1000714 (right) and NGC 3660 (left). Only the outer ring is visible in this image.
Observation data (J2000 epoch)
Right ascension 11h 23m 16.435s[1]
Declination−08° 40′ 06.72″[1]
Helio radial velocity7717 ± 38[2]
Distance360 Mly (110 Mpc)[3]
Apparent magnitude (V)Core: 15.39[3]
Outer ring: 17.72[3]
Apparent magnitude (B)Core: 16.36[3]
Outer ring: 18.09[3]
Inner ring: 20.85[3]
Absolute magnitude (V)Core: -19.43[3]
Outer ring:-17.07[3]
TypeCore: E
Apparent size (V)Core: 7.8 kly (2.4 kpc) (6.20")[3]
Outer ring: 51 kly (15.6 kpc)[3]
Inner ring: 20 kly (6 kpc)[3]
Notable featuresRare double-ringed Hoag-type galaxy
Other designations
6dFGS gJ112316.4-084007, 2MASX J11231643-0840067[4], PGC 1000714
See also: Galaxy, List of galaxies

LEDA 1000714[3] is a ring galaxy in the constellation Crater. LEDA 1000714 is one of a very rare group of galaxies called Hoag-type galaxies,[3] named after the prototype, Hoag's Object – it is estimated that roughly 0.1% of all galaxies are this type.[5][6]

LEDA 1000714 is unusual because it is a Hoag-type galaxy with two nearly round rings, but with different characteristics.[7] It has been nicknamed Burçin's Galaxy, after Burçin Mutlu-Pakdil,[3] the leader of the photometric study of this galaxy.


The structure and photometry of LEDA 1000714 was studied with significant detail in 2017. The core of the galaxy appears to be similar to a elliptical galaxy, and is almost perfectly round, not flattened into a disk. Unlike some ring galaxies, the central core shows no signs of a bar structure connecting the outer ring to the center of the galaxy. This is similar to Hoag's Object, and a number of other galaxies have been found that have a perfectly round center.[3]

The outer galaxy is relatively bright and contains many luminous stars indicative of star formation. However, upon further inspection of the galaxy, it was found that inside the outer ring there is also a faint, diffuse, red inner ring closer to the core. The outer ring appears to be fairly young, at about 0.13 billion years old, while the inner ring is much older, at 5.5 billion years old. This makes the galaxy even more unusual, possibly making it one of a kind.[3]

The details of the formation of Hoag-type objects are still largely unknown.[7] It has been suggested that the near-perfect core of Hoag's Object formed from a sort of "bar instability" where the central bar structure decays into a rounder core.[8] It may also be due to another galaxy. In the case of LEDA 1000714, because its two rings have significantly different ages, the galaxy's morphology may have come from an anomalous collision with another galaxy, however more data is needed to draw conclusions.[3]


  1. ^ a b Skrutskie, M. (2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708.
  2. ^ a b c "NED results for object 2MASX J11231643-0840067". National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 29 January 2017.
  3. ^ a b c d e f g h i j k l m n o p q Mutlu Pakdil, Burçin; Mangedarage, Mithila; Seigar, Marc S.; Treuthardt, Patrick. "A photometric study of the peculiar and potentially double ringed, non-barred galaxy: PGC 1000714". Monthly Notices of the Royal Astronomical Society. 466 (1): 355–368. arXiv:1701.03530. Bibcode:2017MNRAS.466..355M. doi:10.1093/mnras/stw3107.
  4. ^ "LEDA 1000714". SIMBAD. Centre de données astronomiques de Strasbourg.
  5. ^ Schweizer, Francois; Ford, W. Kent Jr; Jedrzejewski, Robert; Giovanelli, Riccardo (1987). "The structure and evolution of Hoag's object". Astrophysical Journal. 320: 454–463. Bibcode:1987ApJ...320..454S. doi:10.1086/165562.
  6. ^ "The One-armed Outer Ringed Galaxy NGC 4378". NASA/IPAC Extragalactic Database. Retrieved 30 January 2017.
  7. ^ a b Seigar, Marc; Mutlu Pakdil, Burcin; Mangedarage, Mithila; Treuthardt, Patrick M. (2017). "The Nonbarred Double-Ringed Galaxy, PGC 1000714". American Astronomical Society. Bibcode:2017AAS...22914519S.
  8. ^ N. Brosch (1985). "The nature of Hoag's object – The perfect ringed galaxy". Astronomy and Astrophysics. 153 (1): 199–206. Bibcode:1985A&A...153..199B.