NGC 1512

NGC 1512 is a barred spiral galaxy around 38 million light-years from Earth in the constellation Horologium. It has a double ring structure with a so-called nuclear ring around the galactic nucleus and a second ring further out in the main disk. When viewed in UV light, the galaxy shows at least 200 clusters recent star formation activity.

Image Credit: NASA / ESA

A Bright Pearl

A hazy nebulaThis is a false color image from Hubble’s Wide Field Planetary Camera 2 of NGC 1501, a complex planetary nebula located in the constellation of Camelopardalis (The Giraffe). NGC 1501 is a planetary nebula that is just under 5,000 light-years away from us. It has a central star shining brightly from within the nebula’s cloud. This bright pearl embedded in its glowing shell gives rise to the nebula’s popular nickname—the Oyster Nebula.

While NGC 1501’s central star blasted off its outer shell long ago, it still remains very hot and luminous, but it can be difficult to spot through modest telescopes. The star seems to be pulsating, varying quite significantly in brightness over a timescale of just half an hour. While variable stars are not unusual, it is unusual to find one at the heart of a planetary nebula.

Image Credit: ESA / NASA

An Irregular Dwarf

content/uploads/2015/04/i_zwicky_18.jpg”>I_Zwicky_18I Zwicky 18 is a dwarf irregular galaxy located about 59 million light years away. Spectroscopic observations with ground-based telescopes showed that I Zwicky 18 to be almost completely made up of hydrogen and helium, the main ingredients created in the Big Bang, and galaxies with I Zwicky 18’s youthful appearance are typically found only in the early universe. Initial observations with the Hubble Space Telescope suggested an age of 500 million years, but later Hubble observations found faint, older stars in the galaxy, suggesting its star formation started at least one billion years ago and possibly as much as ten billion years ago. It’s possible that the galaxy may have formed around the same time as most other galaxies.

Image Credit: NASA / ESA

A Neighborhood Dwarf

A case of suspended animation?The speckling of stares in this image taken by the Hubble Space Telescope image seems to show an array of different cosmic objects, actually forms a single body—the nearby dwarf galaxy known as Leo A. Its few million stars are so sparsely distributed that distant galaxies in the background can be seen behind it. Leo A is about 2.5 million light-years from Earth and is a member of the Local Group of galaxies, a group that includes the Milky Way.

Image Credit: NASA / ESA

Some Really Big Stars

R136 observed with WFC3This Hubble image shows the central region of the Tarantula Nebula in the Large Magellanic Cloud. The young and dense star cluster R136 can be seen the lower right of the image. This cluster contains hundreds of young blue stars. One of them is the most massive star detected in the universe to date.

Dozens of stars in the cluster exceed 50 solar masses, and nine very massive stars are all more than 100 times more massive than the Sun. The most massive is R136a1—weighing in at more than 250 solar masses.

Image Credit: NASA / ESA

A Chaotic Dwarf

The mysteries of UGC 8201The galaxy UGC 8201 is classified as a dwarf irregular galaxy because of its small size and chaotic structure. It’s a bit less than15 million light-years away in the constellation of Draco (the Dragon). As with most dwarf galaxies, it is a member of a larger group of galaxies, in this case, the M81 galaxy group. This group is one of the nearby neighbors to the Local Group of galaxies which contains our galaxy, the Milky Way.

Image Credit: ESA / NASA

Galactic Photobombing

The galaxies NGC 4496A and NGC 4496B dominate this image, but despite appearing to be side-by-side, they actually very far apart, NGC 4496A is 47 million light-years from Earth, and NGC 4496B is 212 million light-years away. They only appear to overlap because of a chance alignment. They are too far from each other to interact.

Image Credit: NASA / ESA

Stardust

Planck's DustNot the Hoagy Carmichael tune. The real dust out among the stars. The European Space Agency Planck Space Telescope‘s ability to measure the temperature of the coldest dust particles provides a better understanding of the physical processes at play in the spaces between stars, and in regions of star formation.

This image covers a portion of the sky about 50 degrees square. It is a false-color combination constructed from Planck‘s two highest frequency channels (557 and 857 Gigahertz, corresponding to wavelengths of 540 and 350 µm), and an image obtained at 100 µm with NASA’s Infrared Astronomical Satellite. Red corresponds to temperatures as cold 12° above absolute zero, and white to significantly warmer ones (on order a few tens of degrees) in regions where massive stars are currently forming. These dust structures “local” within 500 light-years of the sun.

Image Credit: ESA/NASA

NGC 6217

NGC 6217 is a barred spiral galaxy located about 67 million light years away in the constellation Ursa Minor. It’s characterized as a starburst galaxy undergoing a higher rate of star formation than a typical galaxy. As a result, the galaxy’s spectrum is dominated by stellar photoionization from young, hot stars.

Image Credit: NASA / ESA

Mergers and Acquisitions

One from manyThis is an odd galaxy known as NGC 1487. It’s not a single galaxy but two or more galaxies in the act of merging. Each of the old galaxies has lost almost all traces of its original appearance as the stars and gas have been thrown about by gravitational interactions. Unless one of the merging galaxies is very much bigger than the other(s), galaxies are always disrupted by the violence of the merging process, so it’s essentially impossible to determine exactly what the original galaxies looked like or how many of them there were. In this case, it may be that this NGC 1487 is the merger of several dwarf galaxies that were previously part of a small group.

Although older yellow and red stars can be seen in the outer regions of the new galaxy, its general appearance is dominated by bright blue stars that probably formed in a burst of star formation triggered by the merger.

Image Credit: ESA / NASA

Mergers and Acquisitions and Blue Blobs

galex-view-m81_m82The Hubble Space Telescope has resolved some strange objects nicknamed “blue blobs” and found them to be brilliant blue clusters of stars born in the swirls and eddies of a galactic smashup 200 million years ago. These “blue blobs” exist along a wispy bridge of gas strung among three colliding galaxies, M81, M82, and NGC 3077about 12 million light-years away from Earth. This is not a place astronomers expect to find star clusters because the gas filaments should be too thin to allow enough material to accumulate and actually build so many stars. The star clusters in this diffuse structure might have formed from gas collisions and subsequent turbulence which locally enhanced the density of the gas streams.

Image Credit: NASA, ESA

A Top Down View of a Spiral Galaxy

NGC1309_HLANGC 1309 lies on the banks of the constellation Eridanus (The River) about 100 million light-years away. It about 30,000 light-years across or about one third the size of our Milky Way galaxy. Bluish clusters of young stars and dust lanes trace out NGC 1309’s spiral arms, winding around an older yellowish star population at the galaxy’s core.

NGC 1309’s recent supernova and Cepheid variable stars have been used to derive calibration data for the expansion of the Universe.

Image Credit: NASA / ESA

frEGGs

Free-floating Evaporating Gaseous Globules (frEGGs) were first seen in Hubble’s famous image of the Eagle Nebula. Because these knots of cold interstellar gas are dark, we only notice them near where new stars are forming and emitting intense UV light which erodes away. most of the neighboring gas.

This Hubble image also features a pair of young, giant stares. The one on the left is a giant O-type blue-white; the one right is a supergiant B-type. Both types burn their fuel quickly, and supergiants end up as supernovae.

Image Credit: NASA / ESA

A Holiday Wreath in Space

RS PuppisThis Hubble Space Telescope image resembles a holiday wreath full of sparkling lights. The bright star RS Puppis is at the center of the image and is wrapped in a cocoon of reflective dust lit by the star. RS Puppis is huge, ten times more massive than our sun and 200 times larger. It’s one of the most luminous stars in the class of known as Cepheid variables and brightens and dims over a six-week cycle. Its average intrinsic brightness is 15,000 times greater than our Sun’s.

The surrounding nebula flickers in brightness as pulses of light from the Cepheid move outwards. Hubble has taken a series of photos of light flashes rippling across the nebula in a phenomenon known as a “light echo.” Several can be seen in this picture, most easily the ones moving toward seven o’clock. Even though light travels at around 300,000 km/s, the nebula is so large that reflected light can actually be photographed traversing the nebula. Using these reflections, astronomers are able to measure these light echoes and accurately compute the distance to RS Puppis—6,500 light-years (with a margin of error of only one percent).

Image Credit: NASA