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

A Cosmic Smile

A smiling lensThis is is the galaxy cluster SDSS J1038+4849, and it seems to be smiling with its two orange eyes and white button nose. The two eyes are very bright galaxies, and the misleading smile lines are arcs caused by an effect known as strong gravitational lensing.

Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them. They act as cosmic lenses which can magnify, distort, and bend the light coming from behind them. In this special case of gravitational lensing, a ring—known as an Einstein Ring—is produced by this bending of light. The gaps in the ring are a consequence of the inexact and not-quite-symmetrical alignment of the source, lens, and observer.

Image Credit: ESA / NASA

A Carina Nebula Dust Pillar

Carina Dust PillarThis cosmic pillar of gas and dust is almost a couple of light-years wide. It’s a part one of our galaxy’s largest star forming regions, the Carina Nebula, visible in southern skies. The nebula is around 7,500 light-years away. While the pillar has been shaped by the winds and radiation of the nebula’s young, hot, massive stars, it’s interior is home to stars in the process of formation. A penetrating infrared view shows the pillar is dominated by two, narrow, energetic jets blasting outward from a hidden infant star.Carina Pillar IRImage Credits: ESA / NASA