A Dwarf Galaxy

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

A Top Down View

A young star takes centre stageThe reflection nebula spiraling out of this star looks a bit like a snail’s shell.The star V1331 Cyg is located in a dark cloud and is classified as a Young Stellar Object, but it is starting to contract to become a main sequence star similar to the Sun.

From our point of view V1331Cyg is special because we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from its circumstellar disc. In the case of V1331Cyg we are looking straight into the polar jet driven by the star that is clearing the dust. This point of view give us an almost undisturbed view of the star and its immediate surroundings, allowing astronomers to study it in greater detail and look for features that might suggest the formation of a very low-mass object (a planet) in the outer circumstellar disk.

Image Credit: ESA / NASA

A Dusty Galaxy

A galactic cloak for an exploding starThis is NGC 4424, a galaxy in the constellation of Virgo. It is not visible with the naked eye but has been captured here by the Hubble Space Telescope. Although it may not be obvious from this more or less edge-on image, NGC 4424 is a spiral galaxy.

To the left of NGC 4424 there are a couple of other bright objects. The brighter is another, smaller galaxy known as LEDA 213994, and the object closer to NGC 4424 is an star in our Milky Way.

Image Credit: ESA

Star Dust

BetaPictorisDustThus far, Beta Pictoris is the only star which astronomers have detected a giant planet orbiting in a directly-imaged debris disk. The planet, which was discovered at the European Souther Observatory in 2009, goes around the star once every 18 to 20 years. It is being watch to see how a large planet distorts the massive gas and dust encircling the star. These observations should yield new information about how planets are born around young stars. Beta Pictoris is only about 20 million years old.

The images above were taken with Hubble’s Space Telescope Imaging Spectrograph in its coronagraphic imaging mode.  The coronagraph blocks out the glare of the central star so that the disk can be seen. The visible-light images trace the disk to within about 650 million miles of the star. The giant planet orbits at around 900 million miles.

Comparison of the 1997 and 2012 images shows that the distribution of the dust has not changed much over 15 years despite the fact that the entire structure is moving in orbit the star. This implies that the disk’s structure has been smooth and continuous, at least over the period between the Hubble observations.

One more thing … The Beta Pictoris disk is exceptionally dusty. That may have been caused by recent major collisions among unseen planet and asteroid-sized objects in the disk. One bright glob of dust and gas could be the result of the pulverization of a Mars-sized object in a giant collision. (Marvin was unavailable for comment.)

Image Credit: NASA / ESA