In celebration of the 27th anniversary of the launch of the NASA/ESA Hubble Space Telescope in 1990, astronomers used the legendary telescope to take a portrait of spiral galaxies NGC 4302 and NGC 4298.
This image of a pair of spiral galaxies NGC 4302 and NGC 4298 was released to celebrate the 27th anniversary of the launch of the NASA/ESA Hubble Space Telescope. Image credit: NASA / ESA / M. Mutchler, STScI.
NASA and ESA astronomers celebrate Hubble’s birthday each year with a spectacular image. This year’s anniversary image features a pair of spiral galaxies known as NGC 4302 and NGC 4298.
The pair was discovered by the English astronomer William Herschel in 1784.
Such objects were first simply called ‘spiral nebulas,’ because it wasn’t known how far away they were. In the early 20th century, Edwin Hubble discovered that galaxies are other island cities of stars far outside our own Milky Way Galaxy.
NGC 4302 (edge-on galaxy) and NGC 4298 (tilted galaxy) are approximately 55 million light-years away. They reside in the constellation Coma Berenices in the Virgo Cluster, a group of nearly 2,000 individual galaxies.
These galaxies look quite different because we see them angled at different positions on the sky. They are actually very similar in terms of their structure and contents.
From our view on Earth, researchers report an inclination of 90 degrees for NGC 4302, which is exactly edge on. NGC 4298 is tilted 70 degrees.
NGC 4298 is about 45,000 light-years in diameter, about one third the size of the Milky Way. At 17 billion solar masses, it is less than 2% of the Milky Way Galaxy’s one trillion solar masses.
NGC 4302 is about 87,000 light-years in diameter, which is about 60% the size of the Milky Way. It is about 110 billion solar masses, approximately one-tenth of the Milky Way’s mass.
In NGC 4298, the telltale, pinwheel-like structure is visible, but it’s not as prominent as in some other spiral galaxies.
In NGC 4302, dust in the disk is silhouetted against rich lanes of stars. Absorption by dust makes the galaxy appear darker and redder than its companion. A large blue patch appears to be a giant region of recent star formation.
At their closest points, the galaxies are separated from each other in projection by only around 7,000 light-years. Given this very close arrangement, astronomers are intrigued by the galaxies’ apparent lack of any significant gravitational interaction; only a faint bridge of neutral hydrogen gas appears to stretch between them.
The long tidal tails and deformations in their structure that are typical of galaxies lying so close to each other are missing completely.
Astronomers have found very faint tails of gas streaming from the two galaxies, pointing in roughly the same direction — away from the center of the Virgo Cluster. They have proposed that the pair is a recent arrival to the cluster, and is currently falling in towards the cluster center and the galaxy Messier 87 lurking there.
The Hubble data were taken with the Wide Field Camera 3 (WFC3) instrument between January 2 and January 22, 2017.
This color composite (hi-res version) was assembled from images taken in three visible light bands.
