Brown Dwarf

BrownDwarfThis animation shows the coldest brown dwarf found to date. It also the fourth closest system to our Sun. WISE J085510.83-071442.5 is a very dim object that was noticed because of its rapid motion across the sky. It first showed up in two infrared images taken six months apart in 2010 by the Wide-field Infrared Survey Explorer, or WISE (the orange triangles). Two more images of the object were taken with the Spitzer Space Telescope in 2013 and 2014 (green triangles). Because the two satellites are in different orbits, their data could be used to calculate the distance to the brown dwarf: 7.2 light-years. The Spitzer data were used to show that the body appears to be roughly the same temperature as the Earth’s North Pole (-48 to -13 °C).

Image Credit: NASA

A “Young” Supernova Remnant

g306_wideAstronomers estimate that a supernova explosion occurs perhaps a couple of times a century in the Milky Way. The expanding blast wave and hot stellar debris slowly dissipate over hundreds of thousands of years, eventually mixing with and becoming indistinguishable from interstellar gas. The Swift satellite uncovered the previously unknown remains of a shattered star during an X-ray survey of the galaxy’s central regions. The new object, named G306.3-0.9 after it’s coordinates in the sky,is among the youngest of the 300+ known supernova remnants in the Milky Way. Analysis indicates that G306.3–0.9 is probably less than 2,500 years old. That would make it one of the 20 youngest supernova remnants identified.

This composite image of G306.3–0.9 (the blob in the lower left) was stitched together using data from Chandra X-ray observations (blue), infrared data acquired by the Spitzer Space Telescope (red and cyan) and radio observations (purple) from the Australia Telescope Compact Array.

G306_Swift_XRTjpgThe image on the left was taken in February, 2011, using Swift’s X-ray Telescope as part of the Galactic Plane Survey. The dots in the image indicate where X-rays struck the detector. Despite this short 8.5-minute exposure, the extended circular patch of G306.3–0.9 stands out quite nicely.

Image Credits: NASA