| 词条 | NGC 1721 |
| 释义 |
| name = NGC 1721 | image = Galaxy group in Eridanus (NGC 1721, NGC 1723, NGC 1725, and NGC 1728).jpg | image_size = 220px | caption = Galaxy group in Eridanus showing NGC 1721, NGC 1723, NGC 1725, and NGC 1728 | credit = Kopernik Observatory & Science Center, Vestal NY | epoch = J2000 | pronounce = | constellation name = Eridanus | ra = {{RA|04|59|17.4}}[1] | dec = {{DEC|-11|07|07}} [1] | z = 0.015010 [1] | h_radial_v = 4 500 ± 9 km/s [1] | gal_v = 4 388 ± 10 km/s [1] | dist_ly = {{convert|200|Mly|Mpc|1|abbr=on|lk=on}} {{hub|0.73}} [1] | group_cluster = | type = | mass = | stars = | appmag_v = | size_v = 36.92 by 17.58 kpc [1] | notes = | names = | references = }}NGC 1721 is a lenticular galaxy NGC 1721 is a Dreyer Object (a now archaic astronomical term), meaning that it was included in the original New General Catalogue by JLE Dreyer.[4] References1. ^1 2 3 4 5 6 {{cite web | url = http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+1721&extend=no | title = NED results for object NGC 1721 | publisher = NASA/IPAC Extragalactic Database (NED) | accessdate = March 15, 2012 }} {{Sky|04|59|17.4|-|11|07|07|200000000}}{{Ngc20}}{{Galaxy}}{{galaxy-stub}}2. ^{{Cite web|url=http://cseligman.com/text/atlas/ngc17.htm#1721|title=cseligman.com|last=|first=|date=|website=|publisher=|access-date=}} 3. ^{{Cite web|url=http://www.deepskypedia.com/wiki/NGC_1723_Group|title=NGC 1723 Group|last=|first=|date=|website=DeepSkyPedia|publisher=|access-date=}} 4. ^{{Cite journal|title=Observations of nebulae with the 36-inch refractor of the Lick Observatory - by S. W. Burnham (Publications of the Lick Observatory)|last=|first=|date=|publisher=|bibcode = 1894PLicO...2..168B}} 3 : Eridanus (constellation)|Lenticular galaxies|NGC objects |
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