Galaxies NGC 4733, NGC 4754, NGC 4762

Object Description

NGC 4754, 4762
NGC 4754, 4762: NGC 4762 (left) and NGC 4754 (right). Section of the Sloan Digitized Sky Survey [147]

This small group of 3 galaxies was discovered on March 15, 1784 by Wilhelm Herschel using his 18.7 inch telescope. He cataloged them as follows: II 73 (NGC 4733), I 25 = II 74 (NGC 4754) and II 75 (NGC 4762). With I 25 and II 74 he mistakenly made a double entry for the same galaxy (NGC 4754). He described I 25 as «bright, small, in a line with 2 stars». The description for II 74 and II 75 reads as follows: «Two, nearly parallel. The preceding pretty bright nearly round. The following pretty bright very much extended. 8 or 10' distance». Both positions measured relatively from the star 34 Virginis and visual descriptions match. [463]

The two galaxies NGC 4754 and NGC 4762 are assigned to the Hubble class SB0 and are therefore barred spirals with less pronounced spiral arms. However, while we are looking almost exactly at the edge of NGC 4762, we only see NGC 4754 at a medium angle. In addition, there is a strong difference in brightness between a round, inner and an elliptical outer part of the latter galaxy, so that both galaxies do not look very similar in the telescope.

The following distances and radial velocities can be found at Simbad for the three galaxies over the last 20 years: NGC 4733: 13.5-19.1 Mpc, 905-928 km/s — NGC 4754: 15.9-19.8 Mpc, 1317-1377 km/s - NGC 4762: 10.8-22.6 Mpc, 973-1006 km/s. [145]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
NGC 473312 51 06.8+10 54 44E1.7 x .412.7918
NGC 475412 52 17.6+11 18 48LB M4.4 x 2.411.5139623
NGC 476212 52 56.2+11 13 48LB M8.6 x 2.011.198032

Finder Chart

The pretty galaxy pair NGC 4754/4762 is located in the constellation Virgo (Virgo), almost 2.5 degrees west of Vindemiatrix (ε Virginis) and should so not hard to find. NGC 4733 stands about half a degree off to the southwest. The galaxies are best observed from February to June.

Chart NGC 4754
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

200 mm aperture: There are countless galaxies in the constellation Virgo, some of which are very interesting. The galaxies NGC 4754 and NGC 4762 form a very nice pair, which are visible together in fields of view beyond 30 arc minutes. Although they are both assigned to the same Hubble type, they look quite different due to the different viewing angles. The first of the two appears very elongated at 1:5 and structures (knots) are already indicated at medium magnification. It has a bright, compact core.

Nearly 10 arc minutes west of this very beautiful galaxy is NGC 4733. Unlike its partner, it appears round with a fairly smooth increase in brightness toward the core.

Frank H. Leiter

References

144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
463«Catalogue of one thousand new nebulae and clusters of stars» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1786; DOI:10.1098/rstl.1786.0027