A members-only galaxy club: This new Hubble image shows a handful of galaxies in the constellation of Eridanus (The River). NGC 1190, shown here on the right of the frame, stands apart from the rest; it belong to an exclusive club known as Hickson Compact Group 22 (HCG 22). There are four other members of this group, all of which lie out of frame: NGC 1189, NGC 1191, NGC  1192, and NGC 1199. The other galaxies shown here are nearby  galaxies 2MASS J03032308-1539079 (centre), and dCAZ94 HCG 22-21 (left), both of which are  not part of HCG 22. Hickson Compact Groups are incredibly tightly bound groups of galaxies. Their discoverer Paul Hickson observed only 100 of these objects, which he described in his HCG catalogue in the 1980s. To earn the Hickson Compact Group label, there must be at least four members — each one fairly bright and compact. These short-lived groups are thought to end their lives as giant elliptical galaxies, but despite knowing much about their form and destiny, the role of compact galaxy groups in galactic formation and evolution is still unclear. These groups are interesting partly for their self-destructive tendencies. The group members interact, circling and pulling at one another until they eventually merge together, signalling the death of the group, and the birth of a large galaxy. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Luca Limatola.

Name: 2MASS J03032308-1539079, dCAZ94 HCG 22-21, HCG 22, NGC 1190
Type: Local Universe : Galaxy
Category: Galaxies
Constellation: Eridanus
Distance: 110 million light years
Release date: 9 December 2013, 10:00
Credit: ESA/Hubble & NASA Acknowledgement: Luca Limatola

A stellar sneezing fit: Look at the bright star in the middle of this image. Achoo! It has just sneezed. This sight will only last for a few thousand years — a blink of an eye in the young star's life. If you could carry on watching for a few years you would realise it's not just one sneeze, but a sneezing fit. This young star is firing off salvos of super-hot, super-fast gas — Achoo! Achoo! — before it finally exhausts itself. These bursts of gas have shaped the turbulent surroundings, creating structures known as Herbig-Haro objects. These objects are formed from the star's energetic "sneezes". These salvos can contain as much mass as our home planet, and cannon into nearby clouds of gas at hundreds of kilometres per second. Shock waves form, such as the U-shape below this star. Unlike most other astronomical phenomena, as the waves crash outwards, they can be seen moving across human timescales. Soon, this star will stop sneezing, and grow up to be a star like the Sun. This region is actually home to several interesting objects. The star at the centre of the frame is a variable star named V633 Cassiopeiae, with Herbig-Haro objects HH 161 and HH 164 forming parts of the horseshoe-shaped loop emanating from it. The slightly shrouded star just to the left is known as V376 Cassiopeiae, another variable star that has succumbed to its neighbour's infectious sneezing fits; this star is also sneezing, creating yet another Herbig-Haro object — HH 162. Both stars are very young and are still surrounded by dusty material left over from their formation, which spans the gap between the two A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Gilles Chapdelaine. For more information about these objects, see Hubblecast 49: Supersonic jets from newborn stars.

Name: HH 164
Type: Milky Way : Star : Evolutionary Stage : Young Stellar ObjectMilky Way : Star : Circumstellar Material : Outflow
Category: Stars
Constellation: Cassiopeia
Release date: 16 December 2013, 10:00
Credit: ESA/Hubble & NASAAcknowledgement: Gilles Chapdelaine

Flat as a pancake: Located some 25 million light-years away, this new Hubble image shows spiral galaxy ESO 373-8. Together with at least seven of its galactic neighbours, this galaxy is a member of the NGC 2997 group. We see it side-on as a thin, glittering streak across the sky, with all its contents neatly aligned in the same plane. We see so many galaxies like this — flat, stretched-out pancakes — that our brains barely process their shape. But let us stop and ask: Why are galaxies stretched out and aligned like this? Try spinning around in your chair with your legs and arms out. Slowly pull your legs and arms inwards, and tuck them in against your body. Notice anything? You should have started spinning faster. This effect is due to conservation of angular momentum, and it’s true for galaxies, too. This galaxy began life as a humungous ball of slowly rotating gas. Collapsing in upon itself, it spun faster and faster until, like pizza dough spinning and stretching in the air, a disc started to form. Anything that bobbed up and down through this disc was pulled back in line with this motion, creating a streamlined shape. Angular momentum is always conserved — from a spinning galactic disc 25 million light-years away from us, to any astronomer, or astronomer-wannabe, spinning in his office chair.

Name: ESO 373-8
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Antlia
Distance: 25 million light years
Release date: 23 December 2013, 10:00
Credit: ESA/Hubble & NASA

Messier 65 through the years: The 1st of March 1780 was a particularly productive night for Charles Messier. Combing the constellation of Leo for additions to his grand astronomical catalogue, he struck on not one, but two, new objects. One of those objects is seen here: Messier 65. "Nebula discovered in Leo: It is very faint and contains no star," he jotted down in his notebook. But he was wrong — as we now know, Messier 65 is a spiral galaxy containing billions upon billions of stars. All Messier saw was a faint diffuse light, nothing like the fine detail here, so we can forgive his mistake. If he had had access to a telescope like Hubble, he could have spied these stunning, tightly wound purple spiral arms and dark dust lanes, encircling a bright centre crammed with stars. Almost exactly 233 years later in March of this year, one of the stars within Messier 65 went supernova (not seen in this image), rivalling the rest of the entire galaxy in brightness. This, the first Messier supernova of 2013, is now fading, and the serene beauty of M65 is returning.

Name: Messier 65, SN 2013am
Type: Local Universe : Star : Evolutionary Stage : SupernovaLocal Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Leo
Distance: 40 million light years
Release date: 30 December 2013, 10:00
Credit: ESA/Hubble & NASA