An image captured by the Hubble Space Telescope portrays the irregular galaxy NGC 7250, along with the star TYC 3203-450-1, which is much closer and thus from the Earth looks much brighter than a whole galaxy. That star’s presence makes studying the galaxy more difficult because its light interferes with NGC 7250’s dimmer light, polluting the observations of an object that’s interesting because of its peculiar characteristics.
The NGC 7250 galaxy, also known as PGC 68535, UGC 11980, MCG+07-45-024, Mrk 907 or Z 530-22, is cataloged as an irregular galaxy, a category that includes galaxies that don’t fall into the various groups distinguished by specific shapes. It has a length of about 25,000 light years and is about 45 million light years away from the Earth. It was discovered in 1790 by astronomer William Herschel.
Irregular galaxies can be interesting to study in order to understand the reason for their shape, in the case of NGC 7250 there is also the fact that it’s a so-called starburst galaxy, which means that within it there are high levels of star formation. These two things can be linked because if NGC 7250 is the result of the merger between two galaxies, the gas clouds in the two original galaxies are expected to have been subjected to such a gravitational shock that triggered the birth of new stars.
Galactic mergers is an interpretation of the fact that NGC 7250 shows the presence of two cores at its center. The process seems to be still going on with the consequence that the galaxy we see today has an irregular shape. If each of the original galaxies had a supermassic black hole at their center, one can expect that in the future a single galactic core will form and that the two black holes will eventually merge as well.
All this makes the NGC 7250 galaxy interesting to study but its distance is in the order of a million times higher than that of the star TYC 3203-450-1. The image published was assembled by putting together a series of photos taken by the Hubble Space Telescope’s Wide Field Camera 3 (WFC3) instrument. The light emitted by the star is a problem in studying NGC 7250 but hopefully astronomers will still able to discover its secrets.