II Zwicky 28 is an

interacting Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interactions o ...

ring galaxy A ring galaxy is a galaxy with a circle-like appearance. Hoag's Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region co ...

at a distance of approximately 390 million

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

. The sparkling pink and purple loop in Zw II 28 is not a typical ring galaxy due to the fact that it does not seem to have the usual visible central companion. For many years it was thought to be a lone circle on the sky, but observations using the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...

have shown that there may be a possible companion lurking just inside the ring, where the loop appears to double back on itself. The galaxy is only a faint

IRAS The Infrared Astronomical Satellite (Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten mo ...

source, which may indicate a lower level of star formation than other rings, however it has a high Hα luminosity, similar to other ring galaxies. It displays strong Balmer absorption lines interior to the ring, and it is possible that a major burst of star formation has recently occurred, using up a large fraction of the galaxy's molecular reservoir, and depleting its dust content. Its bright foreground star is about 1585 light-years away.

References

Ring galaxies Zwicky objects Orion (constellation) {{Galaxy-stub