NGC 248: Two Glowing Nebulas in the Small Magellanic Cloud, Seen by Hubble

NASA's Hubble Space Telescope photographed two nebulas that sit so that they look like one — together called NGC 248. They lie in the Small Magellanic Cloud, a dwarf galaxy that orbits our Milky Way as a satellite.

What the picture shows

• Why they glow red: intense radiation from the brilliant stars at their centers heats hydrogen in each nebula.
• Size: about 60 light-years long and 20 light-years wide.
• Distance: the Small Magellanic Cloud is roughly 200,000 light-years away, in the southern constellation Tucana, and NGC 248 is one of many glowing hydrogen nebulas in it.
• Discovery: the astronomer Sir John Herschel found them in 1834.

Why astronomers are looking

The image is part of the Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). Astronomers are using Hubble to learn how dust differs in galaxies with far fewer heavy elements — the ingredients dust is made from.

• The Small Magellanic Cloud has between a fifth and a tenth of the heavy elements the Milky Way has.
• Because it is so close, its dust can be studied in great detail.
• Most star formation happened early in the universe's history, when heavy elements were much scarcer than now — so the Small Magellanic Cloud is a window on what dust was like then.

The study's principal investigator, Karin Sandstrom of the University of California, San Diego, points out that this matters for understanding the history of our own galaxy as well, because dust plays a critical part in how a galaxy works and how it forms stars.

Sources

Based on "Festive Nebulas Light Up Milky Way Galaxy Satellite," NASA Image and Video Library; NASA material, not copyrighted and in the public domain; rewritten in hubnx's own words. The image itself, credited to NASA, ESA, STScI, K. Sandstrom (University of California, San Diego) and the SMIDGE team, is not shown here.