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Форум » Досуг » Космос » NGC 45
NGC 45
ingvarr
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NGC 45 (другие обозначения — ESO 473-1, IRAS00115-2327, MCG −4-1-21, DDO 223, UGCA 4, AM 0011-232, PGC 930) — спиральная галактика с перемычкой (SBd) в созвездии Кит.

Этот объект входит в число перечисленных в оригинальной редакции «Нового общего каталога».

Галактика была открыта английским астрономом Джоном Гершелем 11 ноября 1835.
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ingvarr
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NGC 45 (= PGC 930)
Discovered (Nov 11, 1835) by John Herschel
Also observed (Jul 1, 1899 to Jun 30, 1900) by Herbert Howe
A magnitude 10.6 spiral galaxy (type SA(s)dm?) in Cetus (RA 00 14 04.0, Dec -23 10 52)
Historical Identification: Per Dreyer, NGC 45 (= GC 23 = JH 2313, 1860 RA 00 06 48, NPD 113 57.2) is "extremely faint, large, very gradually very little brighter middle, large star in contact following (to the east)". The position precesses to RA 00 13 54.6, Dec -23 10 28, about 9 seconds of time west of the center of the galaxy listed above, but well within its outline, so the identification is certain.
Discovery Notes: The diffuse nature of the galaxy must have presented problems in determining its position, as the brightest star in the field, 7th magnitude HD 941, is to the southwest, not the east; but since Herschel's position for the galaxy was too far to the west, the star would have seemed further east in comparison. And although apparently not noted by anyone at the time, Howe stated that the NGC right ascension was 10 seconds of time too small, so his position was essentially dead-center on the galaxy.
Physical Information: Based on a recessional velocity of 465 km/sec, NGC 45 is only 22 million light years away, at the lower end of redshift-independent distance estimates of 20 to 40 million light years. Given that and its apparent size of 8.6 by 5.5 arcmin, it is about 50 thousand light years across. It has been suggested NGC 45 and 24 (which see for a view of the region between the galaxies) are a pair, as they are not far apart (about two degrees, which would correspond to less than a million light years at their probable distance), and have similar recessional velocities. The latter galaxy is probably 20 to 30 million light years away, so if they really are a pair, it would support the distance estimate in this entry; but both galaxies' distances are very uncertain, so the presumption that they are a pair cannot be viewed with confidence.

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