Sunday, June 25, 2017

The N44 Superbubble

What created this gigantic hole? The vastemission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250light-year hole and astronomers are trying to figure out why. One possibility is particle windsexpelled by massive stars in the bubble's interior that are pushing out the glowing gas. This answer was found to be inconsistent with measured wind velocities, however. Another possibility is that the expanding shells of oldsupernovas have sculpted the unusual space cavern. An unexpected clue of hot X-rayemitting gas was recently been detected escaping the N44 superbubble. The featured image was taken in three very specific colors by the huge 8-meter Gemini South Telescope onCerro Pachon in Chile.
Image Credit & CopyrightGemini Obs.AURA,NSF

Hubble uses Gravitational Lens to Capture Disk Galaxy

Acting as a “natural telescope” in space, the gravity of the extremely massive foreground galaxy cluster MACS J2129-0741 magnifies, brightens, and distorts the far-distant background galaxy MACS2129-1 in the upper-right corner of this image. (View an annotated image highlighting the gravitationally-lensed galaxy.)

By combining the power of this "natural lens" in space with the capability of NASA's Hubble Space Telescope, astronomers made a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang.  Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, say researchers. This is the first direct observational evidence that at least some of the earliest so-called "dead" galaxies — where star formation stopped — somehow evolve from a Milky Way-shaped disk into the giant elliptical galaxies we see today.

Read more: Hubble Captures Massive Dead Disk Galaxy that Challenges Theories of Galaxy Evolution

Image Credit: NASA, ESA, M. Postman (STScI), and the CLASH team

Hubble Space Telescope

Markarian's Chain to Messier 64

Top to bottom, this colorful and broad telescopic mosaic links Markarian's Chain of galaxies across the core of the Virgo Cluster to dusty spiral galaxy Messier 64. Galaxies are scattered through the field of view that spans some 20 full moons across a gorgeous night sky. The cosmic frame is also filled with foreground stars from constellations Virgo and the well-groomed Coma Berenices, and faint, dusty nebulae drifting above the plane of the Milky Way. Look carefully for Markarian's eyes. The famous pair of interacting galaxies is near the top, not far from M87, the Virgo cluster's giant elliptical galaxy. At the bottom, you can stare down Messier 64, also known as the Black Eye Galaxy. The Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Virgo Cluster galaxies are about 50 million light-years distant, but M64 lies a mere 17 million light-years away.
Image Credit & CopyrightRogelio Bernal Andreo (Deep Sky Colors)

Tuesday, June 20, 2017

The Massive Stars in Westerlund

Star cluster Westerlund 1 is home to some of the largest and most massive stars known. It is headlined by the star Westerlund 1-26, a red supergiant star so big that if placed in the center of our Solar System, it would extend out past the orbit of Jupiter. Additionally, the young star cluster is home to 3 other red supergiants, 6 yellow hypergiant stars, 24 Wolf-Rayet stars, and several even-more unusual stars that continue to be studied. Westerlund 1 is relatively close-by for a star cluster at a distance of 15,000 light years, givingastronomers a good laboratory to study the development of massive stars. The featured image of Westerlund 1 was taken by the Hubble Space Telescope toward the southernconstellation of the Altar (Ara). Although presently classified as a "super" open cluster,Westerlund 1 may evolve into a low massglobular cluster over the next billion years.
Image Credit: ESA/Hubble & NASA

Hubble Space Telescope

Thursday, June 15, 2017

Eliptical Galaxy with Outer Shells and Plumbs

Can you see them? This famous Messier object M89, a seemingly simple elliptical galaxy, is surrounded by faint shells and plumes. The cause of the shells is currently unknown, but possibly tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years. Alternatively the shells may be like ripples in a pond, where a recent collision with another large galaxy created density waves that ripple through this galactic giant. Regardless of the actual cause, the featured imagehighlights the increasing consensus that at least some elliptical galaxies have formed in the recent past, and that the outer halos of most large galaxies are not really smooth but have complexities induced by frequent interactions with -- and accretions of -- smaller nearby galaxies. The halo of our own Milky Way Galaxy is one example of suchunexpected complexityM89 is a member of the nearby Virgo cluster of galaxies which lies about 50 million light years distant.
Image Credit & Copyright: Mark Hanson

Tuesday, June 13, 2017

The Great Nebula in Carina

In one of the brightest parts of Milky Way lies a nebula where some of the oddest things occur. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebulas. The Keyhole Nebula (NGC 3324), the bright structure just to the right of the image center, houses several of these massive stars and has itself changed its appearance. The entire Carina Nebulacaptured here, spans over 300 light years and lies about 7,500 light-years away in the constellation of CarinaEta Carinae, themost energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, butthen faded dramatically. While Eta Carinae itself maybe on the verge of a supernova explosion,X-ray images indicate that much of the Great Nebula in Carina has been a veritable supernova factory.
Image Credit & Copyright: Amit Ashok Kamble

Monday, June 12, 2017

IC 418: The Spirograph Nebula

What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing toolplanetary nebula IC 418 showspatterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 was probably a well-understood star similar to our Sun. Only a few thousand years ago, IC 418 was probably a common red giantstar. Since running out of nuclear fuel, though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star, visible in the imagecenter. The light from the central core excites surrounding atoms in the nebula causing them to glow. IC 418 lies about 2000 light-years away and spans 0.3 light-years across. This false-color image taken from the Hubble Space Telescope reveals the unusual details.
Image Credit: NASAESA, and the Hubble Heritage Team (STScI/AURA);Acknowledgement: R. Sahai (JPL) et al.

Hubble Space Telescope

Saturday, June 10, 2017

Saturn in the Milky way

Saturn is near opposition in planet Earth's sky. Rising at sunset and shining brightly throughout the night, it also lies near a line-of-sight to crowded starfields, nebulae, and obscuring dust clouds along the Milky Way. Whitish Saturn is up and left of center in this gorgeous central Milky Way skyscape, a two panel mosaic recorded earlier this month. You can find the bright planet above the bowl of the dusty Pipe nebula, and just beyond the end of a dark riverto Antares, alpha star of the constellation Scorpius. For now the best views of the ringed giant planet are from the Saturn-orbiting Cassini spacecraft, though. Diving close, Cassini's Grand Finale orbit number 8 is in progress.
Image Credit & CopyrightMohammad Nouroozi

M27 not a Comet

While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of agaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula.This spectacular color image incorporates broad and narrowband observations recorded by the 8.2 meter Subaru telescope.
Image Credit &Copyright:Data;Subaru, NAOJ,Assembly and Processing;Roberto Colombari

Tuesday, June 6, 2017

Beneath the Jupiter

Jupiter is stranger than we knew. NASA's Juno spacecraft has now completed its sixth swoop past Jupiter as it moves around its highlyelliptical orbit. PicturedJupiter is seen from below where, surprisingly, the horizontal bandsthat cover most of the planet disappear intoswirls and complex patterns. A line of white oval clouds is visible nearer to the equator.Recent results from Juno show that Jupiter's weather phenomena can extend deep below its cloud tops, and that Jupiter's magnetic fieldvaries greatly with location. Juno is scheduled to orbit Jupiter 37 times with each orbit taking about six weeks.
Image Credit: NASAJunoSwRIMSSSGerald Eichstädt & Seán Doran


Saturday, June 3, 2017

Spiral Galaxy NGC 6744

Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo appearing as a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight. This remarkably distinct and detailed galaxy portraitcovers an area about the angular size of the full moon. In it, the giant galaxy's yellowish core is dominated by the light from old, cool stars. Beyond the core, spiral arms filled with young blue star clusters and pinkish star forming regions sweep past a smaller satellite galaxy at the lower left, reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.
Image Credit & CopyrightDaniel Verschatse