NGC 4298/4302
The two bright galaxies NGC 4298 and NGC 4302 are located in a distance of ~49...53 million light years in the constellation "Coma Berenices" and
were already discovered in 1784 by F.W. Herschel with his 18.7" telescope. Both galaxies do not only stand coincidentally in the same direction - they are
actually gravitationally bound to each other.
NGC 4298 is the smaller of the two galaxies. It is a spiral galaxy of type SA(rs)c. Its tightly wound spiral arms are described as "patchy". With a true
diameter of 45,000 light-years it is not even half the size of our Milky Way and its mass is only about 15 billion solar masses. In the center one of the very
rare "Intermediate Black Holes" with a mass of 20,000 to 500,000 solar masses is suspected.
NGC 4302 on the other hand is a normal spiral galaxy of type "Sc", which we see almost from the side - "EdgeOn" as one says. It is also a Seyfert
galaxy with an active galactic nucleus (AGN). With a diameter of 110,000 light-years and a mass of 100 billion solar masses, it has similar dimensions
as our home galaxy. A closer look reveals that the bulge is not round, but rather angular - indicative of a bar we are looking at from the side. Of particular
interest are the concise dust clouds, which are not only present in the form of filaments, but also form large, massive, coherent areas. Many of the
filaments are curved, indicating interaction with the interstellar medium (ISM). In the case of NGC 4302, the galaxy is moving radially at fairly high
velocity towards the center of the Virgo cluster.
That both galaxies interact with each other can be seen by the fact that the stars in NGC 4298 are pulled towards NGC 4302, furthermore a "tidal bridge",
i.e. a light bridge of stars is present as well as a HI- tail. Also the increased star formation in NGC 4298 is an indication of gravitational binding.
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The two galaxies make a wonderful sight in my 20 inch telescope. Both appear quite bright. If you increase the magnification to 210x, you can see a faint
dust lane in NGC 4302, but more indicated than really visible. The core area is slightly brighter. NGC 4298 on the other hand is the typical example of a
rather structureless galaxy. Except for an increase in brightness towards the core, no further details are visible. But that's not a big deal, because it's all
about the overall impression - which is just fantastic!
