The halo of galaxy Messier 87The giant elliptical galaxy Messier 87 is surrounded by a huge halo. An increase in brightness in the top-right part of this halo and the motion of planetary nebulae in the galaxy are the last remaining signs of a medium-sized galaxy that collided with M87.

This wide field image also contains many other galaxies forming the Virgo Cluster, of which Messier 87 is the largest member. The two galaxies at the edge of the top right of the frame are nicknamed “the Eyes.”

Image Credit: ESO

A Different Kind of Sunspot

Here’s the European Southern Observatory’s description of this animation—

Spots on extreme horizontal branch stars (right) appear to be quite different from the dark sunspots on our own Sun (left), but both are caused by magnetic fields. The spots on these hot, extreme stars are brighter and hotter than the surrounding stellar surface, unlike on the Sun where we see spots as dark stains on the solar surface that are cooler than their surroundings. The spots on extreme horizontal branch stars are also significantly larger than sunspots, covering up to a quarter of the star’s surface. While sunspots vary in size, a typical size is around an Earth-size planet, 3000 smaller than a giant spot on an extreme horizontal branch star.

Video Credit: ESO

Go here for information about extreme horizontal branch stars.

The Medusa Nebula

ESO’s Very Large Telescope images the Medusa NebulaESO’s Very Large Telescope in Chile captured this image of the Medusa Nebula (also known Abell 21 and Sharpless 2-274). As the star at the heart of this nebula made its final transition into the final stage of its existence, it blew off its outer layers into space, forming this colorful cloud. The Sun will go through a similar process in a few billion years.

Image Credit: ESO

A Ring Galaxy

A Cosmic Hit and RunThe odd galaxy next to the bright foreground star in this picture is the Vela ring galaxy, visible as a bright core surrounded by a blue halo. As the name suggests, this ring galaxy is located in the southern constellation of Vela (The Sails). It is notable for its compact core and large circular belt of gas and stars.

It is thought that a ring galaxy like this is created when a small galaxy passes through the center of a larger one, triggering a shock wave that spreads outward. That forces gas to the galaxy’s periphery where it begins to collapse and form new stars. The Vela ring galaxy is unusual in that it actually exhibits at least two rings, suggesting that its collision was not a recent one.

Image Credit: ESO

NGC 3603

NGC 3603NGC 3603 is an open cluster of stars situated in the Carina spiral arm of the Milky Way around 20,000 light-years away from the Solar System. It’s the densest concentration of very massive stars known in the galaxy, and their strong ultraviolet radiation and stellar winds have cleared the gas and dust, giving an unobscured view of the cluster.

Image Credit: ESO

Gum 41

Gum 41In the middle of this little-known nebula called Gum 41, brilliant hot young stars are giving off energetic radiation causing the surrounding hydrogen to glow a characteristic red. The nebula is located 7300 light-years from Earth. Australian astronomer Colin Gum discovered it on photographs taken at the Mount Stromlo Observatory near Canberra, and included it in his catalogue of 84 emission nebulae, published in 1955. Gum 41 is actually one small part of a bigger structure called the Lambda Centauri Nebula, also known by the more exotic name of the Running Chicken Nebula.

Image Credit: ESO

The Great Barred Spiral Galaxy

NGC 1365NGC 1365 is enormous. It is one of the largest galaxies known to astronomers—over 200,000 light-years across. This, plus the sharply defined bar of old stars across its structure is why it is also known as the Great Barred Spiral Galaxy. Astronomers believe that the Milky Way, which is only half as big, may look very similar to this galaxy. The bright centre of the galaxy is thought to be caused by huge amounts of superhot gas ejected from the ring of material circling a central black hole. Young luminous hot stars, born in the interstellar clouds, give the arms their blue color. The bar and spiral pattern rotates, with one full turn taking about 350 million years. NGC 1365 is about 61 million light-years away in the constellation Fornax (the Furnace).

Image Credit: ESO

A Celestial Diamond Ring

Celestial Diamond RingESO’s Very Large Telescope in Chile captured this eye-catching image of planetary nebula PN A66 33 (aka Abell 33). This beautiful blue bubble in space was created when an aging star blew off its outer layers, and it is, by chance, aligned with a foreground star. From the Earth’s point of view the pair bears an uncanny resemblance to a diamond engagement ring.

Image Credit: ESO


FORS1 First Light - Spiral galaxy NGC 1288This is the spiral galaxy NGC 1288 in the southern constellation Fornax. The distance to this galaxy is about 300 million light-years, and it is receding from us at around of 4500 km/s. It’s roughly 200,000 light-years or about twice the diameter of the Milky Way.

Image Credit: ESO

The Blinking Galaxy

NGC 6118NGC 6118 is a grand-design spiral galaxy, and it shines bright in this image taken by ESO’s Very Large Telescope. Its central bar and tight spiral arms are clearly visible. The galaxy is sometimes known to amateur astronomers as the “Blinking Galaxy” because this relatively faint, fuzzy object can appear to flick into existence when viewed through small telescopes and then suddenly disappear again as the observer’s eye position shifted.

Image Credit: ESO

A New Star Factory

Star cluster NGC 6193 and nebula NGC 6188Star cluster NGC 6193 is in the center of this image. It contains thirty or so bright stars and forms the heart of the Ara OB1 association (so named because it is in the southern constellation of Ara, the Altar). The two brightest stars are very hot giants. Together, they provide the main source of illumination for the nearby emission nebula, the Rim Nebula, or NGC 6188, visible to the right of the cluster.

The ultraviolet radiation and intense stellar wind from the stars of NGC 6193 seem to be driving the next generation of star formation in the surrounding clouds of gas and dust. As the gas and duct collapse, it forms new stars.

Image Credit: ESO

It’s Raining Iron on WASP-76b

The star WASP-76 is about 360 light-years from Earth in the constellation of Pisces. This animations shows the orbit of one of its planets called WASP-76b. The planet’s orbit is very close to the star, and it is tidally locked, so on side faces the star all the time. Day side temperatures range above 2400 C, high enough to vaporise metals. Winds circulate iron vapor to the cooler night side where it condenses and falls as iron droplets.

Video Credit: ESO