Skip to main content
  1. Home
  2. Space
  3. News

See where stars are born and where they die in the dwarf galaxy Sextans B

Georgina Torbet
By
Sextans B is an irregular dwarf galaxy, meaning that it is irregularly shaped and smaller than our galaxy, the Milky Way. It lies around 4.5 million light-years from Earth and is located in the constellation Sextans in the southern sky. Captured with the Nicholas U. Mayall 4-meter Telescope, this image of Sextans B features red-colored star-forming regions near the galaxy’s center. Surrounding the galaxy are several bright stars that are located much closer to us in our galaxy, identified by the crisscross patterns created by light interacting with the structure of the telescope, as well as numerous fuzzy-looking background galaxies that appear small because they are much farther away than Sextans B.
Captured with the Nicholas U. Mayall 4-meter Telescope, this image of Sextans B features red-colored star-forming regions near the galaxy’s center. Surrounding the galaxy are several bright stars that are located much closer to us in our galaxy, identified by the crisscross patterns created by light interacting with the structure of the telescope, as well as numerous fuzzy-looking background galaxies that appear small because they are much farther away than Sextans B. KPNO/NOIRLab/NSF/AURA Data obtained and processed by: P. Massey (Lowell Obs.), G. Jacoby, K. Olsen, & C. Smith (AURA/NSF) Image processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), M. Zamani (NSF’s NOIRLab) & D. de Martin (NSF’s NOIRLab)

Galaxies in our universe come in a range of sizes, like the enormous IC 1101 which is 50 times the size of the Milky Way and is estimated to be up to 8 million light-years across — hence why it’s known as the Godzilla Galaxy. On the other end of the scale, you can find relatively tiny galaxies which can be as small as just 200 light-years across, like the teeny Segue 2.

But the fact a galaxy is tiny doesn’t mean it’s not of scientific interest, as this image of the dwarf galaxy Sextans B shows. Located 4.5 million light-years away and with a mass equivalent to 200 million times the mass of the sun, the dwarf galaxy is only a few thousand light-years in diameter. But despite this, it hosts a whole range of astronomical phenomena squeezed into its relatively diminutive size.

The most obvious features are the glowing red clouds near the center of the image which are composed of hydrogen. These are the birthplaces of stars, where the clouds clump together and eventually create a gravitational pull strong enough to form a new star.

Related

The galaxy contains not only the nurseries of stars but also their graveyards, in the form of planetary nebulae. Sextans B is notable for being among the smallest galaxies to contain planetary nebulae, which are beautiful ring-like structures that are formed when a red giant star approaches the end of its life, though they aren’t visible in the image. As a star runs out of fuel, it throws off its outer layers which form elaborate structures in space.

The image was taken using the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory, and as well as Sextans B it shows many other galaxies in the background which appear fuzzy, as well as stars in our galaxy which are located much closer to us and so shine brightly.

Editors' Recommendations

Topics
Hubble snaps a cluster in our galaxy bursting with stars
The scattered stars of the globular cluster NGC 6355 are strewn across this image from the NASA/ESA Hubble Space Telescope. NGC 6355 is a galactic globular cluster that resides in our Milky Way galaxy's inner regions. It is less than 50,000 light-years from Earth in the constellation Ophiuchus.
Peering into clouds of dust to understand star formation
This image of the spectacular Sh2-54 nebula was taken in infrared light using ESO’s VISTA telescope at Paranal Observatory in Chile. The clouds of dust and gas that are normally obvious in visible light are less evident here, and in this light we can see the light of the stars behind the nebulae now piercing through.
Hubble sees the ghostly light of lost, wandering stars
These are Hubble Space Telescope images of two massive clusters of galaxies named MOO J1014+0038 (left panel) and SPT-CL J2106-5844 (right panel). The artificially added blue color is translated from Hubble data that captured a phenomenon called intracluster light. This extremely faint glow traces a smooth distribution of light from wandering stars scattered across the cluster. Billions of years ago the stars were shed from their parent galaxies and now drift through intergalactic space.
James Webb spots early galaxies similar to our Milky Way
The power of JWST to map galaxies at high resolution and at longer infrared wavelengths than Hubble allows it look through dust and unveil the underlying structure and mass of distant galaxies. This can be seen in these two images of the galaxy EGS23205, seen as it was about 11 billion years ago. In the HST image (left, taken in the near-infrared filter), the galaxy is little more than a disk-shaped smudge obscured by dust and impacted by the glare of young stars, but in the corresponding JWST mid-infrared image (taken this past summer), it’s a beautiful spiral galaxy with a clear stellar bar.
How to watch two astronauts perform their first spacewalk on Friday
A photo of Expedition 68 Flight Engineer and NASA spacewalker Josh Cassada on Dec. 22, 2022, preparing a roll-out solar array for its deployment on the International Space Station's Port-4 truss segment as the orbiting lab flew 264 miles above the Indian Ocean off the coast of South Africa.
Watch key moments of SpaceX triple-booster Falcon Heavy launch
SpaceX's Falcon Heavy heading to space.
Enjoy these amazing space images by NASA’s oldest active astronaut
Don Pettit aboard the space station.
Watch SpaceX footage of Falcon Heavy from launch to landing
SpaceX's Falcon Heavy heading to space.
This must be the most beautiful image ever of a rocket launch
A SpaceX Falcon 9 rocket launching from Florida.
Still no joy for Lucy’s stuck solar array, NASA is giving up for now
see lucy spacecraft slingshot past earth fly by
Light pollution is cutting off views of the night sky for many
A startling analysis from Globe at Night — a citizen science program run by NSF’s NOIRLab — concludes that stars are disappearing from human sight at an astonishing rate. The study finds that, to human eyes, artificial lighting has dulled the night sky more rapidly than indicated by satellite measurements. The study showcases the unique contributions that citizen scientists can make in essential fields of research. This graphic illustrates how the greater the amount of light pollution, and therefore skyglow, the fewer the stars that are visible. The numeric scale is similar to the one used by Globe at Night participants. 
First spacewalk of the year sees astronauts dealing with a sticky foothold
Spacewalkers (from left) Koichi Wakata and Nicole Mann are pictured installing hardware on the space station preparing the orbiting lab for its next roll-out solar array.
Browse through 3B celestial objects in Milky Way survey
Astronomers have released a gargantuan survey of the galactic plane of the Milky Way. The new dataset contains a staggering 3.32 billion celestial objects — arguably the largest such catalog so far. The data for this unprecedented survey were taken with the US Department of Energy-fabricated Dark Energy Camera at the NSF’s Cerro Tololo Inter-American Observatory in Chile, a Program of NOIRLab.