Excerpt from americanlivewire.com
A low-mass red dwarf star passed through the outer Oort Cloud 70,000 years back in the closest approach made by any star into our system, discovers a team of researchers from various countries.
Lying in the constellation Monoceros and known as Scholtz’s star, it is a part of a binary system and has 8% the mass of the sun. Its companion, a brown dwarf, is said to have 6%.
The lowest end of the stellar spectrum, brown dwarfs are larger than gas giants but not as much so as to sustain hydrogen fusion for a larger period of time.
Due to its faint appearance, Scholtz’s star was discovered only a year ago by astronomer Ralf Dieter-Scholz in Potsdam, Germany, through the use of NASA’s WISE (Wide Field Infrared Survey Explorer), which mapped the entire sky in infrared during the years 2010 and 2011.
At the same time, the radial velocity of the star depicted that it was moving away from the solar system much faster than expected.
These motions led the researchers to conclude that either the star is headed toward our system, or moving away from it.
After analyzing the data, Mamajek concluded, “…The radial velocity measurements were consistent with it running away from the Sun’s vicinity–and we realized it must have had a close flyby in the past.”
Through the use of computer models, it was seen that the star passed about 5 trillion miles from our solar system around 70,000 years ago.
Mamajek and his team are 98 percent certain Scholtz’s star traveled through the outer Oort Cloud.
Although Scholtz’s star is 10th magnitude, too dim to be seen with the naked eye, it is magnetically active, which can cause it to flare at times and become significantly brighter. If this happened during its close approach to our solar system, prehistoric humans might have actually seen it.
The researchers published their findings in Astrophysical Journal Letters.
The lowest end of the stellar spectrum, brown dwarfs are larger than gas giants but not as much so as to sustain hydrogen fusion for a larger period of time.
Due to its faint appearance, Scholtz’s star was discovered only a year ago by astronomer Ralf Dieter-Scholz in Potsdam, Germany, through the use of NASA’s WISE (Wide Field Infrared Survey Explorer), which mapped the entire sky in infrared during the years 2010 and 2011.
At the same time, the radial velocity of the star depicted that it was moving away from the solar system much faster than expected.
These motions led the researchers to conclude that either the star is headed toward our system, or moving away from it.
After analyzing the data, Mamajek concluded, “…The radial velocity measurements were consistent with it running away from the Sun’s vicinity–and we realized it must have had a close flyby in the past.”
Through the use of computer models, it was seen that the star passed about 5 trillion miles from our solar system around 70,000 years ago.
Mamajek and his team are 98 percent certain Scholtz’s star traveled through the outer Oort Cloud.
Although Scholtz’s star is 10th magnitude, too dim to be seen with the naked eye, it is magnetically active, which can cause it to flare at times and become significantly brighter. If this happened during its close approach to our solar system, prehistoric humans might have actually seen it.
The researchers published their findings in Astrophysical Journal Letters.
Spacecraft found on Mars – and it’s ours
Excerpt from skyandtelescope.com
By Kelly Beatty
On December 25, 2003, a British-built lander dropped to the Martian surface and disappeared without a trace. Now we know what happened to it. It's hard to overstate how valuable the main camera aboard the Mars Reconnaissance Orbiter has been. The craft's High-Resolution Imaging Science Experiment, or HiRISE, uses a 20-inch (0.5-m) f/24 telescope to record details on the Martian surface as small as 0.3 m (about 10 inches).
Primarily it's a powerful tool for studying Martian geology at the smallest scales, and NASA scientists sometimes use it to track the progress (and even the arrivals) of their rovers. Beagle 2 on Mars The clamshell-like Beagle 2 lander weighed just 30 kg, but it was well equipped to study Martian rocks and dust — and even to search for life. Beagle 2 consortium But the HiRISE team has also been on a years-long quest to find the remains of Beagle 2, a small lander that had hitchhiked to the Red Planet with the European Space Agency's Mars Express orbiter. It descended to the Martian surface on Christmas Day in 2003 and was never heard from again. Space aficionados have debated its fate ever since. Did parachute failure lead to a crash landing? Did strong surface winds flip the saucer-shaped craft upside down? Did the Martians take it hostage? Now, thanks to HiRISE, we know more of the story.
Images taken in February 2013 and June 2014 of the landing area in Isidis Planitia showed promising blips near the edge of each frame. A follow-up color view, acquired on December 15th and released three days ago, show a bright spot consistent with Beagle 2. The fully-opened lander would have been less than 2 m (6½ feet) across, so the craft is only barely resolved. Apparently the spacecraft made it to the surface intact, opened its clamshell cover, and had partially deployed its four petal-shaped solar-cell panels before something went awry. Beagle 2 seen from orbit by HiRISE
One encouraging clue is that the bright reflection changes position slightly from image to image, consistent with sunlight reflecting off different lander panels. Two other unusual spots a few hundred meters away appears to be the lander's parachute and part of the cover that served as a shield during the 5½-km-per-second atmospheric descent...
It's hard to overstate how valuable the main camera aboard the Mars Reconnaissance Orbiter has been. The craft's High-Resolution Imaging Science Experiment, or HiRISE, uses a 20-inch (0.5-m) f/24 telescope to record details on the Martian surface as small as 0.3 m (about 10 inches). Primarily it's a powerful tool for studying Martian geology at the smallest scales, and NASA scientists sometimes use it to track the progress (and even the arrivals) of their rovers.
Beagle 2 consortium
Now, thanks to HiRISE, we know more of the story. Images taken in February 2013 and June 2014 of the landing area in Isidis Planitia showed promising blips near the edge of each frame. A follow-up color view, acquired on December 15th and released three days ago, show a bright spot consistent with Beagle 2. The fully-opened lander would have been less than 2 m (6½ feet) across, so the craft is only barely resolved. Apparently the spacecraft made it to the surface intact, opened its clamshell cover, and had partially deployed its four petal-shaped solar-cell panels before something went awry.
NASA / JPL / Univ. of Arizona / Univ. of Leicester
The initial images didn't just show up. They'd been requested and searched by Michael Croon of Trier, Germany, who'd served on the Mars Express operations team. Croon had asked for specific camera targeting through a program called HiWish, through which anyone can submit suggestions for HiRISE images. Read more about this fascinating sleuthing story.
"Not knowing what happened to Beagle 2 remained a nagging worry," comments Rudolf Schmidt in an ESA press release about the find. "Understanding now that Beagle 2 made it all the way down to the surface is excellent news." Schmidt served as the Mars Express project manager at the time.
Built by a consortium of organizations, Beagle 2 was the United Kingdom's first interplanetary spacecraft. The 32-kg (73-pound) lander carried six instruments to study geochemical characteristics of the Martian surface and to test for the presence of life using assays of carbon isotopes. It was named for HMS Beagle, the ship that carried a crew of 73 (including Charles Darwin) on an epic voyage of discovery in 1831–36.
- See more at: http://www.skyandtelescope.com/astronomy-news/beagle-2-lander-found-on-mars-01192015/#sthash.5KSZ8V6W.dpuf