Starship Asterisk*

bystander wrote:Smoke Ring for a Halo (DI Cha)
ESA Hubble Picture of the Week | 2015 Oct 26

[img3="Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt (geckzilla.org)"]http://www.spacetelescope.org/static/ar ... w1543a.jpg[/img3][hr][/hr]

Two stars shine through the centre of a ring of cascading dust in this image taken by the NASA/ESA Hubble Space Telescope. The star system is named DI Cha, and while only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.

As this is a relatively young star system it is surrounded by dust. The young stars are moulding the dust into a wispy wrap.

The host of this alluring interaction between dust and star is the Chamaeleon I dark cloud — one of three such clouds that comprise a large star-forming region known as the Chamaeleon Complex. DI Cha's juvenility is not remarkable within this region. In fact, the entire system is among not only the youngest but also the closest collections of newly formed stars to be found and so provides an ideal target for studies of star formation.

[img3="Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt (geckzilla.org)"]http://www.spacetelescope.org/static/ar ... w1543a.jpg[/img3][hr][/hr]

Two stars shine through the centre of a ring of cascading dust in this image taken by the NASA/ESA Hubble Space Telescope. The star system is named DI Cha, and while only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.

As this is a relatively young star system it is surrounded by dust. The young stars are moulding the dust into a wispy wrap.

The host of this alluring interaction between dust and star is the Chamaeleon I dark cloud — one of three such clouds that comprise a large star-forming region known as the Chamaeleon Complex. DI Cha's juvenility is not remarkable within this region. In fact, the entire system is among not only the youngest but also the closest collections of newly formed stars to be found and so provides an ideal target for studies of star formation.

[img3="Credit: ESO, A. M. Lagrange (Université Grenoble Alpes)"]http://cdn.eso.org/images/large/potw1543a.jpg[/img3][hr][/hr]

Observations by ESO’s planet-finding instrument, SPHERE, a high-contrast adaptive optics system installed on the third Unit Telescope of ESO’s Very Large Telescope, have revealed the edge-on disc of gas and dust present around the binary star system HD 106906AB.

HD 106906AB is a double star located in the constellation of Crux (The Southern Cross). Astronomers had long suspected that this 13 million-year-old stellar duo was encircled by a debris disc, due to the system’s youth and characteristic radiation. However, this disc had remained unseen — until now! The system’s spectacular debris disc can be seen towards the lower left area of this image. It is surrounding both stars, hence its name of circumbinary disc. The stars themselves are hidden behind a mask which prevent their glare from blinding the instrument.

These stars and the disc are also accompanied by an exoplanet, visible in the upper right, named HD 106906 b, which orbits around the binary star and its disc at a distance greater than any other exoplanet discovered to date — 650 times the average Earth–Sun distance, or nearly 97 billion kilometres. HD 106906 b has a mammoth mass of up to 11 times that of Jupiter, and a scorching surface temperature of 1500 degrees Celsius.

Thanks to SPHERE, HD 106906AB has become the first binary star system to have both an exoplanet and a debris disc successfully imaged, providing astronomers with a unique opportunity to study the complex process of circumbinary planet formation.

bystander wrote:Starburst Galaxy Messier 94
ESA Hubble Picture of the Week | 2015 Oct 19

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This image shows the galaxy Messier 94, which lies in the small northern constellation of the Hunting Dogs (Canes Venatici), about 16 million light-years away.

Within the bright ring around Messier 94 new stars are forming at a high rate and many young, bright stars are present within it – thanks to this, this feature is called a starburst ring.

The cause of this peculiarly shaped star-forming region is likely a pressure wave going outwards from the galactic centre, compressing the gas and dust in the outer region. The compression of material means the gas starts to collapse into denser clouds. Inside these dense clouds, gravity pulls the gas and dust together until temperature and pressure are high enough for stars to be born.

[c][attachment=0]potw1542a[1].jpg[/attachment][/c][hr][/hr]

This image shows the galaxy Messier 94, which lies in the small northern constellation of the Hunting Dogs (Canes Venatici), about 16 million light-years away.

Within the bright ring around Messier 94 new stars are forming at a high rate and many young, bright stars are present within it – thanks to this, this feature is called a starburst ring.

The cause of this peculiarly shaped star-forming region is likely a pressure wave going outwards from the galactic centre, compressing the gas and dust in the outer region. The compression of material means the gas starts to collapse into denser clouds. Inside these dense clouds, gravity pulls the gas and dust together until temperature and pressure are high enough for stars to be born.

[img3="Credit: K. Wagner, D. Apai (U Arizona), M. Kasper (ESO), M. Robberto (STSci)"]http://cdn.eso.org/images/screen/potw1542a.jpg[/img3][hr][/hr]

ESO’s SPHERE, a planet-hunting instrument installed on the Very Large Telescope in Chile, has uncovered an unusual structure around a nearby adolescent star named HD 100453.

HD 100453 lies over 350 light-years away in the constellation of Centaurus (The Centaur), and is engulfed by a swirling disc of gas and dust, visible in red and white in this image. Tantalisingly, two faint spiral arms can be seen extending from the disc, possibly formed due to the influence of as-yet-unseen planets lurking within. This spiral disc is uniquely symmetrical, and is one of the smallest spiral discs ever observed around another star — an impressive demonstration of SPHERE’s capabilities.

SPHERE is a powerful planet finder, letting us directly image alien worlds, and the dusty discs in which they form around stars in the Milky Way. It does this by blocking out the dazzling light from the parent star, which would be found at the centre of the image (in place of the black circle, which is hiding the star and its closest surrounding). Exploring the regions around young stars such as HD 100453 can provide critical clues as to how planets and stars form and grow throughout our galaxy.

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Dark smudges almost block out a rich star field in this new image captured by the Wide Field Imager camera, installed on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. The inky areas are small parts of a huge dark nebula known as the Coalsack, one of the most prominent objects of its kind visible to the unaided eye. Millions of years from now, chunks of the Coalsack will ignite, rather like its fossil fuel namesake, with the glow of many young stars.

The Coalsack Nebula is located about 600 light-years away in the constellation of Crux (The Southern Cross). This huge, dusky object forms a conspicuous silhouette against the bright, starry band of the Milky Way and for this reason the nebula has been known to people in the southern hemisphere for as long as our species has existed.

The Spanish explorer Vicente Yáñez Pinzón first reported the existence of the Coalsack Nebula to Europe in 1499. The Coalsack later garnered the nickname of the Black Magellanic Cloud, a play on its dark appearance compared to the bright glow of the two Magellanic Clouds, which are in fact satellite galaxies of the Milky Way. These two bright galaxies are clearly visible in the southern sky and came to the attention of Europeans during Ferdinand Magellan’s explorations in the 16th century. However, the Coalsack is not a galaxy. Like other dark nebulae, it is actually an interstellar cloud of dust so thick that it prevents most of the background starlight from reaching observers. ...