June 25, 2019

20.06.10: The Low Down on WASP-12b.

A bizarre exo-world just got stranger in the past month, but not in the way many news outlets would have you believe. WASP-12b is destined for a short life, one that we many have been fortunate enough to catch it in the middle of. The story starts in 2008, with the transiting exoplanet’s discovery by the UKs Wide Area Search for Planets (WASP) array. The primary star, WASP-12, is a yellow dwarf located 600 light years distant in the constellation Auriga. Even at that time, it was known that WASP-12b was strange; it whizzed around its star in only 26 hours and had to be sizzling. Now, follow-up measurements with the Hubble Space Telescope and its newly installed Cosmic Origins Spectrograph have indeed revealed a world in peril; at 2800° degrees Fahrenheit, WASP-12b is bloated up to three times the radius of Jupiter, although it only contains 1.4 times its mass. COS was able to identify manganese, tin, and aluminum in the spectra of the atmosphere as the planet transited its host star, using its sensitivity in the ultraviolet to pin down key measurements such as its diameter. This would put the Roche Limit of the planet well beyond what its own gravity can retain. WASP-12b is more than likely feeding material to its stellar host, an act it can’t maintain forever. Calculations show that WASP-12b will cease to exist in about 10 million years or so.  It does, however, give astronomers an opportunity to gather a spectrum for study of a hot Jupiter in action… The WASP-12b story also fueled an avalanche of bad science stories, along the lines of “Cannibal Star 600 Million Light Years Distant Consumes Planet!” as if such a star bent on evil were inbound or headed our way. Never let the facts get in the way of a good story, guys… you keep us science news bloggers employed!

12.06.10: Refurbished Hubble Catches Interstellar Speedster.

New instruments installed aboard the Hubble Space Telescope on the final repair mission are now starting to really show their stuff. Recently, astronomers revealed a new find; a massive star speeding away from the Tarantula Nebula. Located 170,000 light years distant in the Large Magellanic Cloud, this nebula is also sometimes referred to as 30 Doradus or NGC 2070. At the heart of the nebula is a star forming region known as R136. The star in question is speeding outward at an amazing 250,000 mph, or almost 70 miles a second. This would easily span the Earth-Moon distance in one hour! Already, the star has covered about 375 light years in its young estimated 1 to 2 million year long life. What accelerates a star to such a dizzying velocity? One event capable is a nearby supernova explosion. This is unlikely, because any of the siblings within 30 Dor would have been equally young. Another, more likely scenario is that this star had several early encounters with neighboring stars and promptly got flung out of the nebula. 30 Dor boasts several stars in the massive 100+ solar mass category, and is home to some of the largest stars known in the nearby universe.  First indentified in 2006 during a survey conducted at the Siding Spring Observatory in Australia, astronomers got a new view of the stellar runaway when they used it as a calibration target for the newly installed Cosmic Origins Spectrograph. They found a star perhaps 90 times the mass of our Sun unleashing furious stellar winds and carving an enormous bubble in space. COS conducts its observations primarily in the ultraviolet. Observations also confirmed that this star is one single massive entity, and not a close spectroscopic binary. Massive stars such as this are destined for a short life, ending its fusion role as a supernova and eventually leaving a remnant black hole.