A splendid rosy ring galaxy with the rather dry name of Zw II 28 has been photographed by the NASA/ESA Hubble Space Telescope, NASA and the European Space Agency reported on Friday. The beautiful pink and purple galaxy has long represented something of a mystery to astronomers, but the new photograph may help solve the mystery.
According to EarthSky’s Deborah Byrd, a ring galaxy is just what it sounds like — a roughly circle-sized collection of stars grouped around a relatively empty center.
One theory of how they form suggests that ring galaxies start out as normal spiral galaxies just like our Milky Way. At some point, a smaller galaxy attracted by gravity smashes into the core of the larger spiral. A ring of stars then spreads out explosively, leaving a relatively dark and dense core surrounded by the expanding ring of colorful shining stars.
NASA noted that even though two galaxies are colliding, stars rarely smash into each other during the collision. That’s because even the most densely population galaxy is still mostly empty space. Therefore, the work of creating the ring galaxy is all done by gravity rather than by actual physical contact.
Zw II 28 previously mystified astronomers because it appeared to be a single empty ring alone in space. However, NASA’s press release stated that the new observations with the Hubble telescope have detected evidence of the possible second companion galaxy “lurking just inside the ring, where the loop appears to double back on itself.”
What’s intriguing about the collision is that the thick dense gravitational core at the center may eventually collapse in on itself, allowing the birth of hot new stars. Hubble has been used recently to locate new areas where stars and even entire galaxies are being born, including a project announced this week where the space telescope was used in conjunction with the large ALMA earth-based observatory to find new “starburst galaxies.”
The rosy ring galaxy isn’t just beautiful. It could be an important clue to how new stars are born.
[photos ESA/Hubble and NASA]