Scholz's star - shown in this artist's impression - is currently 20 light-years away. But it once came much closerExcerpt from bbc.comAn alien star passed through our Solar System just 70,000 years ago, astronomers have discovered. No othe...
Tag: oort cloud
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.
The Mars Reconnaissance Orbiter captures images of Comet C/2013 A1, also known as Sliding Spring after the observatory which discovered it, as it flies past Mars on October 19th. The comet originated in the Oort Cloud, which is located in the distant reaches of our solar system.
These images were taken by the Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera while the comet flew approximately 86,000 miles from Mars at a speed of 35,700 miles per hour (57,400 km/h) relative to the planet.
Greg Giles
Astrophotographer Damian Peach captures Siding Spring (green smudge at lower-centre) on approach to Mars (saturated star-like object)bbc.comA recently discovered comet has whizzed past Mars, giving scientists a unique chance to study an object from...
Excerpt from
astronomy.com
Comet Siding Spring will pass within about 87,000 miles (139,500 kilometers) of the Red Planet on October 19.
NASA’s extensive fleet of science assets, particularly those orbiting and roving Mars, have front-row seats to image and study a once-in-a-lifetime comet flyby Sunday, October 19.
Comet C/2013 A1, also known as Comet Siding Spring, will pass within about 87,000 miles (139,500 kilometers) of the Red Planet — less than half the distance between Earth and our Moon and less than one-tenth the distance of any known comet flyby of Earth.
Siding Spring’s nucleus will come closest to Mars around 2:27 p.m. EDT, hurtling at about 126,000 mph (56 kilometers per second). This proximity will provide an unprecedented opportunity for researchers to gather data on both the comet and its effect on the martian atmosphere.
Siding Spring came from the Oort Cloud, a spherical region of space surrounding our Sun and occupying space at a distance between 5,000 and 100,000 astronomical units (1 AU is the average Earth-Sun distance). It is a giant swarm of icy objects believed to be material left over from the formation of the solar system.
Siding Spring will be the first comet from the Oort Cloud to be studied up close by spacecraft, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago.
Some of the best and most revealing images and science data will come from assets orbiting and roving the surface of Mars. In preparation for the comet flyby, NASA maneuvered its Mars Odyssey orbiter, Mars Reconnaissance Orbiter, and the newest member of the Mars fleet, Mars Atmosphere and Volatile EvolutioN (MAVEN), in order to reduce the risk of impact with high-velocity dust particles coming off the comet.
In addition, Earth-based and space telescopes, including NASA’s iconic Hubble Space Telescope, will be in position to observe the unique celestial object. The agency’s astrophysics space observatories — Kepler, Swift, Spitzer, Chandra — and the ground-based Infrared Telescope Facility on Mauna Kea, Hawaii —will be tracking the event.
Comet C/2013 A1, also known as Comet Siding Spring, will pass within about 87,000 miles (139,500 kilometers) of the Red Planet — less than half the distance between Earth and our Moon and less than one-tenth the distance of any known comet flyby of Earth.
Siding Spring’s nucleus will come closest to Mars around 2:27 p.m. EDT, hurtling at about 126,000 mph (56 kilometers per second). This proximity will provide an unprecedented opportunity for researchers to gather data on both the comet and its effect on the martian atmosphere.
Siding Spring came from the Oort Cloud, a spherical region of space surrounding our Sun and occupying space at a distance between 5,000 and 100,000 astronomical units (1 AU is the average Earth-Sun distance). It is a giant swarm of icy objects believed to be material left over from the formation of the solar system.
Siding Spring will be the first comet from the Oort Cloud to be studied up close by spacecraft, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago.
Some of the best and most revealing images and science data will come from assets orbiting and roving the surface of Mars. In preparation for the comet flyby, NASA maneuvered its Mars Odyssey orbiter, Mars Reconnaissance Orbiter, and the newest member of the Mars fleet, Mars Atmosphere and Volatile EvolutioN (MAVEN), in order to reduce the risk of impact with high-velocity dust particles coming off the comet.
In addition, Earth-based and space telescopes, including NASA’s iconic Hubble Space Telescope, will be in position to observe the unique celestial object. The agency’s astrophysics space observatories — Kepler, Swift, Spitzer, Chandra — and the ground-based Infrared Telescope Facility on Mauna Kea, Hawaii —will be tracking the event.
NASA’s asteroid hunter, the Near-Earth Object Wide-field Infrared Survey Explorer, has been imaging and will continue to image the comet as part of its operations. And the agency’s two Heliophysics spacecraft, Solar Terrestrial Relations Observatory and Solar and Heliophysics Observatory, will image the comet. The agency’s Balloon Observation Platform for Planetary Science, a suborbital balloon-carried telescope, already has provided observations of the comet in the lead-up to the close encounter with Mars.
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