H5N1 squad of astronomers using the latest ready of information from ESA's Gaia mission to aspect for high-velocity stars beingness kicked out of the Galaxy were surprised to respect stars instead sprinting inwards -- possibly from some other galaxy. The report is published inwards the mag Monthly Notices of the Royal Astronomical Society.
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| The positions in addition to reconstructed orbits of 20 high-velocity stars, represented on go past times of an artistic thought of our Galaxy, the Milky Way. These stars were identified using information from the bit unloose of ESA’s Gaia mission.The 7 stars shown inwards ruby are sprinting away from the Galaxy in addition to could hold out travelling fast plenty to eventually escape its gravity. Surprisingly, the report revealed equally good 13 stars, shown inwards orange, that are racing towards the Milky Way: these could hold out stars from some other galaxy, zooming correct through our ain [Credit: ESA (artist’s impression in addition to composition); |
Marchetti et al. 2018 (star positions in addition to trajectories); NASA / ESA / Hubble (background galaxies)] Stars circle around our galaxy at hundreds of kilometres per second, in addition to their motions incorporate a wealth of information most the past times history of the Galaxy. The fastest shape of these stars are called hypervelocity stars, which are idea to kickoff their life close the Galactic centre, afterwards to hold out flung towards the border of the Galaxy via interactions alongside the dark hole at its centre.
Only a pocket-sized issue of hypervelocity stars accept always been discovered, in addition to Gaia's latterly published bit information unloose provides a unique chance to aspect for to a greater extent than of them.
"Of the 7 1000000 Gaia stars alongside sum 3D velocity measurements, nosotros institute 20 that could hold out travelling fast plenty to eventually escape from the Milky Way," explains Elena Maria Rossi, 1 of the authors of the novel study, based at Leiden University, inwards the Netherlands.
However, the squad were inwards for a surprise: "Rather than flight away from the Galactic centre, most of the high-velocity stars nosotros spotted appear to hold out racing towards it," adds co-author Tommaso Marchetti. "These could hold out stars from some other galaxy, zooming correct through the Milky Way."
It is possible that these intergalactic interlopers come upward from the Large Magellanic Cloud, a relatively pocket-sized galaxy orbiting the Milky Way, or they may originate from a galaxy fifty-fifty farther afield. If that is the case, they comport the imprint of their site of origin, in addition to studying them at much closer distances than their raise galaxy could supply unprecedented information on the nature of stars inwards some other galaxy -- like inwards a agency to studying Martian textile brought to our planet past times meteorites.
"Stars tin hold out accelerated to high velocities when they interact alongside a supermassive dark hole," Elena explains. "So the presence of these stars powerfulness hold out a sign of such dark holes inwards nearby galaxies. But the stars may equally good accept 1 time been business office of a binary system, flung towards the Galaxy when their companion star exploded equally a supernova. Either way, studying them could state us to a greater extent than most these kinds of processes inwards nearby galaxies."
An option explanation is that the newly identified sprinting stars could hold out native to our Galaxy's halo, accelerated in addition to pushed inwards through interactions alongside 1 of the dwarf galaxies that barbarous towards the Galaxy during its build-up history. Additional information most the historic stream in addition to composition of the stars could aid the astronomers clarify their origin.
New information volition aid to boom downwardly the nature in addition to rootage of these stars alongside to a greater extent than certainty, in addition to the squad volition role ground-based telescopes to respect out to a greater extent than most them. At to the lowest degree 2 to a greater extent than Gaia information releases are planned inwards the 2020s, in addition to each volition supply both to a greater extent than precise in addition to novel information on a larger ready of stars.
"We eventually await sum 3D velocity measurements for upward to 150 1000000 stars," explains co-author Anthony Brown, chair of the Gaia Data Processing in addition to Analysis Consortium Executive. "This volition aid respect hundreds or thousands of hypervelocity stars, sympathise their rootage inwards much to a greater extent than detail, in addition to role them to investigate the Galactic centre surround equally good equally the history of our Galaxy," he adds.
"This exciting lawsuit shows that Gaia is a truthful uncovering machine, providing the Earth for completely unexpected discoveries most our Galaxy," concludes Timo Prusti, Gaia projection scientist at ESA.
Source: Royal Astronomical Society [October 03, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
Only a pocket-sized issue of hypervelocity stars accept always been discovered, in addition to Gaia's latterly published bit information unloose provides a unique chance to aspect for to a greater extent than of them.
"Of the 7 1000000 Gaia stars alongside sum 3D velocity measurements, nosotros institute 20 that could hold out travelling fast plenty to eventually escape from the Milky Way," explains Elena Maria Rossi, 1 of the authors of the novel study, based at Leiden University, inwards the Netherlands.
However, the squad were inwards for a surprise: "Rather than flight away from the Galactic centre, most of the high-velocity stars nosotros spotted appear to hold out racing towards it," adds co-author Tommaso Marchetti. "These could hold out stars from some other galaxy, zooming correct through the Milky Way."
It is possible that these intergalactic interlopers come upward from the Large Magellanic Cloud, a relatively pocket-sized galaxy orbiting the Milky Way, or they may originate from a galaxy fifty-fifty farther afield. If that is the case, they comport the imprint of their site of origin, in addition to studying them at much closer distances than their raise galaxy could supply unprecedented information on the nature of stars inwards some other galaxy -- like inwards a agency to studying Martian textile brought to our planet past times meteorites.
"Stars tin hold out accelerated to high velocities when they interact alongside a supermassive dark hole," Elena explains. "So the presence of these stars powerfulness hold out a sign of such dark holes inwards nearby galaxies. But the stars may equally good accept 1 time been business office of a binary system, flung towards the Galaxy when their companion star exploded equally a supernova. Either way, studying them could state us to a greater extent than most these kinds of processes inwards nearby galaxies."
An option explanation is that the newly identified sprinting stars could hold out native to our Galaxy's halo, accelerated in addition to pushed inwards through interactions alongside 1 of the dwarf galaxies that barbarous towards the Galaxy during its build-up history. Additional information most the historic stream in addition to composition of the stars could aid the astronomers clarify their origin.
New information volition aid to boom downwardly the nature in addition to rootage of these stars alongside to a greater extent than certainty, in addition to the squad volition role ground-based telescopes to respect out to a greater extent than most them. At to the lowest degree 2 to a greater extent than Gaia information releases are planned inwards the 2020s, in addition to each volition supply both to a greater extent than precise in addition to novel information on a larger ready of stars.
"We eventually await sum 3D velocity measurements for upward to 150 1000000 stars," explains co-author Anthony Brown, chair of the Gaia Data Processing in addition to Analysis Consortium Executive. "This volition aid respect hundreds or thousands of hypervelocity stars, sympathise their rootage inwards much to a greater extent than detail, in addition to role them to investigate the Galactic centre surround equally good equally the history of our Galaxy," he adds.
"This exciting lawsuit shows that Gaia is a truthful uncovering machine, providing the Earth for completely unexpected discoveries most our Galaxy," concludes Timo Prusti, Gaia projection scientist at ESA.
Source: Royal Astronomical Society [October 03, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
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