| 词条 | NGC 612 |
| 释义 |
Observation historyThe object was discovered by British astronomer John Herschel on 29 November, 1837.[5] John Louis Emil Dreyer, compiler of the first New General Catalogue of Nebulae and Clusters of Stars, described NGC 612 as a "faint, very small, round, 12th magnitude star to the west."[5] Physical characteristicsNGC 612 has a fairly well-developed luminous disc seen almost edge-on and features a strong dust ring.[3] The galaxy is surrounded by an enormous disc of cool neutral hydrogen gas with a mass of {{val|1.8|e=9}} M☉ distributed in a 140 kpc wide structure along the galactic disc and dust lane of NGC 612. The majority of the gas is relatively settled in regular rotation with a velocity of 8900 km/s. A faint bridge, spanning 400 kpc, exists between NGC 612 and the gas-rich barred spiral galaxy NGC 619, indicating that an interaction between both galaxies occurred at some point. Current or past interaction, such as a merger event, is currently the most likely trigger of NGC 612's radio source.[4] The galaxy has an unusually young star population, with populations throughout the galactic disc having an age of ~0.04 - 0.1 Gyr.[4] See also
References1. ^1 2 3 4 5 6 {{Cite web|url=http://ned.ipac.caltech.edu/?q=byname&out_csys=Equatorial&corr_z=1&omegav=0.73&extend=no&omegam=0.27&img_stamp=YES&out_equinox=J2000.0&objname=NGC%20612&list_limit=5&of=pre_text&hconst=73&obj_sort=RA%20or%20Longitude&keyword=objname|title=NGC 612 NASA/IPAC Extragalactic Database Results|last=|first=|date=|website=ned.ipac.caltech.edu|archive-url=|archive-date=|dead-url=|access-date=2018-10-31}} 2. ^1 {{Cite web|url=http://spider.seds.org/ngc/revngcic.cgi?NGC612|title=Revised NGC Data for NGC 612|website=spider.seds.org|access-date=2018-10-31}} 3. ^1 {{Cite journal|last=Véron-Cetty|first=M. P.|last2=Véron|first2=P.|date=2001|title=Are all radio galaxies genuine ellipticals?|journal=Astronomy & Astrophysics|language=en|volume=375|issue=3|pages=791–796|doi=10.1051/0004-6361:20010902|issn=0004-6361|bibcode=2001A&A...375..791V}} 4. ^1 2 {{Cite journal|last=Emonts|first=B. H. C.|last2=Morganti|first2=R.|last3=Oosterloo|first3=T. A.|last4=Holt|first4=J.|last5=Tadhunter|first5=C. N.|last6=van der Hulst|first6=J. M.|last7=Ojha|first7=R.|last8=Sadler|first8=E. M.|date=2008|title=Enormous disc of cool gas surrounding the nearby powerful radio galaxy NGC 612 (PKS 0131−36)|journal=Monthly Notices of the Royal Astronomical Society|language=en|volume=387|issue=1|pages=197–208|doi=10.1111/j.1365-2966.2008.13142.x|issn=0035-8711}} 5. ^1 2 {{Cite web|url=http://cseligman.com/text/atlas/ngc6.htm#612|title=New General Catalog Objects: NGC 600 - 649|website=cseligman.com|language=en-US|access-date=2018-10-31}} 4 : Astronomical objects discovered in 1837|Discoveries by John Herschel|Lenticular galaxies|NGC objects |
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