Centauri Dreams 9 Sep 2019, 17:49 UTC Our thinking on how planetary systems form includes the accretion of rocky bodies within a disk surrounding a young star, and we’re examining such disks in numerous systems, such as the well studied Beta Pictoris. But the idea of accretion leaves many issues unsettled, such as what happens when large rocky bodies collide in the violent endgame of system formation. The Earth evidently underwent such a collision, with our own Moon being the tangible result.
Forbes articles by Brian Koberlein 9 Sep 2019, 15:26 UTC The Boomerang Nebula is expanding so quickly it is literally colder than deep space.
Bad Astronomy 9 Sep 2019, 13:00 UTC The north pole of Mars has an ice cap with some complex features. There's a relatively permanent deposit (called a basal unit) of sand and dust embedded in water ice that's a kilometer or so thick. On top of that is the polar layered deposit, which is what it sounds like: Zillions of layers of ice with some dust mixed in, probably deposited seasonally layer-by-layer. There's also a thin layer of carbon dioxide ice that gets deposited every winter and which sublimates (turns directly to gas) every spring and summer.
SPACE.com 9 Sep 2019, 10:53 UTC Astronomers have detected a rare pattern in the X-ray bursts coming from a neutron-star system no more than 16,300 light-years away. That star system, MAXI J1621−501, first turned up on Oct. 9, 2017, in data from the Swift/XRT Deep Galactic Plane Survey as an odd point in space flashing unpredictably with X-rays. That was a sign, researchers wrote in a new paper, of a binary system containing both a normal star and either a neutron star or black hole. Both neutron stars and black holes can create unpredictable X-ray patterns as they absorb matter from their companion stars, but in very different ways.
EarthSky Blog 9 Sep 2019, 10:07 UTC Japan’s Hayabusa2 spacecraft – launched in December, 2014 – traveled some 200 million miles to near-Earth asteroid Ryugu. It closed to within 12 miles (20 km) of the asteroid’s surface in June 2018. Hayabusa2 will continue traveling with this asteroid until December 2019, when it’ll begin making its way back to Earth. It’s due to return a sample of the asteroid to scientists in December 2020. In the meantime – in two studies published this summer – the Hayabusa2 mission has already given us valuable information about asteroids like Ryugu. Among other things, it showed that, if an asteroid like Ryugu were headed toward Earth – and if we on Earth decided to send a spacecraft out in an attempt to divert the asteroid – we’d need to take “great care” in the attempt.
Bob Moler's Ephemeris Blog 9 Sep 2019, 04:01 UTC Ephemeris for Monday, September 9th. Today the Sun will be up for 12 hours and 50 minutes, setting at 8:05, and it will rise tomorrow at 7:15. The Moon, 4 days past first quarter, will set at 3:29 tomorrow morning. Two Harvard University astronomers who have studied the interstellar asteroid or comet that was discovered last year ‘Oumuamua are proposing to observe small interstellar meteoroids with a lunar orbiting satellite when they hit the Moon.
The New York Times 8 Sep 2019, 12:10 UTC NEW DELHI — A day after India lost contact with a robotic spacecraft that was launched toward the moon’s South Pole, the chairman of the country’s space agency said on Sunday that the lander had been detected on the moon’s surface. K. Sivan, the director of the Indian Space Research Organization, told national news outlets that a thermal image had been taken by the Chandrayaan-2 mission’s orbiter. He said it was still unclear whether the lander was damaged, though he expected it had experienced a “hard landing.”
SPACE.com 8 Sep 2019, 11:41 UTC Don't be alarmed, but the Fireworks galaxy is exploding. To be fair, it's been exploding for a while — at least since 1917 (give or take the 25 million years that light takes to travel from that galaxy to Earth), when astronomers first glimpsed a large star erupting into a supernova there. Since then, scientists have detected nearly a dozen stellar explosions in the busy galaxy, but none quite like the mysterious green blotch of X-ray light visible in the image above.