One from many: This image, taken by the NASA/ESA Hubble Space Telescope, shows a peculiar galaxy known as NGC 1487, lying about 30 million light-years away in the southern constellation of Eridanus. Rather than viewing a celestial object, it is actually better to think of this as an event. Here, we are witnessing two or more galaxies in the act of merging together to form a single new galaxy. Each progenitor has lost almost all traces of its original appearance, as stars and gas have been thrown hither and thither by gravity in an elaborate cosmic whirl. Unless one is very much bigger than the other, galaxies are always disrupted by the violence of the merging process. As a result, it is very difficult to determine precisely what the original galaxies looked like and, indeed, how many of them there were. In this case, it is possible that we are seeing the merger of several dwarf galaxies that were previously clumped together in a small group. Although older yellow and red stars can be seen in the outer regions of the new galaxy, its appearance is dominated by large areas of bright blue stars, illuminating the patches of gas that gave them life. This burst of star formation may well have been triggered by the merger.

Name: NGC 1487
Type: Local Universe : Galaxy : Type : IrregularLocal Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Eridanus
Distance: 30 million light years
Release date: 1 February 2016, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (Geckzilla)

The icy blue wings of Hen 2-437: In this cosmic snapshot, the spectacularly symmetrical wings of Hen 2-437 show up in a magnificent icy blue hue. Hen 2-437 is a planetary nebula, one of around 3000 such objects known to reside within the Milky Way. Located within the faint northern constellation of Vulpecula (The Fox), Hen 2-437 was first identified in 1946 by Rudolph Minkowski, who later also discovered the famous and equally beautiful M2-9 (otherwise known as the Twin Jet Nebula). Hen 2-437 was added to a catalogue of planetary nebula over two decades later by astronomer and NASA astronaut Karl Gordon Henize. Planetary nebulae such as Hen 2-437 form when an aging low-mass star — such as the Sun — reaches the final stages of life. The star swells to become a red giant, before casting off its gaseous outer layers into space. The star itself then slowly shrinks to form a white dwarf, while the expelled gas is slowly compressed and pushed outwards by stellar winds. As shown by its remarkably beautiful appearance, Hen 2-437 is a bipolar nebula — the material ejected by the dying star has streamed out into space to create the two icy blue lobes pictured here.

Name: Hen 2-437
Type: Milky Way : Nebula : Type : Planetary
Category: Nebulae
Constellation: Vulpecula
Release date: 8 February 2016, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (Geckzilla)

A diamond in the dust: Surrounded by an envelope of dust, the subject of this NASA/ESA Hubble Space Telescope image is a young pre-main-sequence star known as HBC 1. The star is in an immature and adolescent phase of life, hence its classification — most of a Sun-like star’s life is spent in a stage comparable to human adulthood dubbed the main sequence. In this view, HBC 1 illuminates a wispy reflection nebula known as IRAS 00044+6521. Formed from clouds of interstellar dust, reflection nebulae do not emit any visible light of their own and instead — like fog encompassing a lamppost — shine via the light from the stars embedded within. Though nearby stars cannot ionise the nebula’s non-gaseous contents, as with brighter emission nebulae, scattered starlight can make the dust visible. What makes this seemingly ordinary reflection nebula more interesting are three nearby Herbig–Haro objects known as HH 943, HH 943B and HH 943A — which are not visible in this image — located within IRAS 00044+6521 itself. Herbig–Haro objects are small patches of dust, hydrogen, helium and other gases that form when narrow jets of gas ejected by young stars such as HBC 1 collide with clouds of gas and dust. Lasting just a few thousand years, these objects rapidly move away from their parent star before dissipating into space.

Name: IRAS 00044+6521
Type: Milky Way : Nebula : Appearance : Reflection
Category: Nebulae
Constellation: Cassiopeia
Distance: 2700 light years
Release date: 15 February 2016, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt

Blue bubble in Carina: Sparkling at the centre of this beautiful NASA/ESA Hubble Space Telescope image is a Wolf–Rayet star known as WR 31a, located about 30 000 light-years away in the constellation of Carina (The Keel). The distinctive blue bubble appearing to encircle WR 31a, and its uncatalogued stellar sidekick, is a Wolf–Rayet nebula — an interstellar cloud of dust, hydrogen, helium and other gases. Created when speedy stellar winds interact with the outer layers of hydrogen ejected by Wolf–Rayet stars, these nebulae are frequently ring-shaped or spherical. The bubble — estimated to have formed around 20 000 years ago — is expanding at a rate of around 220 000 kilometres per hour! Unfortunately, the lifecycle of a Wolf–Rayet star is only a few hundred thousand years — the blink of an eye in cosmic terms. Despite beginning life with a mass at least 20 times that of the Sun, Wolf–Rayet stars typically lose half their mass in less than 100 000 years. And WR 31a is no exception to this case. It will, therefore, eventually end its life as a spectacular supernova, and the stellar material expelled from its explosion will later nourish a new generation of stars and planets.

Name: WR 31a
Type: Milky Way : Star : Type : Wolf-Rayet
Category: Stars
Constellation: Carina
Distance: 30000 light years
Release date: 22 February 2016, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt

A stellar fingerprint: Showcased at the centre of this NASA/ESA Hubble Space Telescope image is an emission-line star known as IRAS 12196-6300. Located just under 2300 light-years from Earth, this star displays prominent emission lines, meaning that the star’s light, dispersed into a spectrum, shows up as a rainbow of colours marked with a characteristic pattern of dark and bright lines. The characteristics of these lines, when compared to the “fingerprints” left by particular atoms and molecules, can be used to reveal IRAS 12196-6300’s chemical composition. Under 10 million years old and not yet burning hydrogen at its core, unlike the Sun, this star is still in its infancy. Further evidence of IRAS 12196-6300’s youth is provided by the presence of reflection nebulae. These hazy clouds, pictured floating above and below IRAS 12196-6300, are created when light from a star reflects off a high concentration of nearby dust, such as the dusty material still remaining from IRAS 12196-6300’s formation.

Name: IRAS 12196-6300
Type: Milky Way : Star
Category: Stars
Constellation: Crux
Distance: 2300 light years
Release date: 29 February 2016, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (Geckzilla)