Post by Andrei Tchentchik on Jun 26, 2019 18:28:15 GMT 2
(.#225).- The first asteroid from another star has a "hallucinating" form.
The first asteroid from another star has a "hallucinating" form.
By Tristan Vey - Updated on 21/11/2017 at 09:02
For the first time, astronomers have discovered an interstellar asteroid. Astronomers will study this asteroid before it leaves the Solar System. They have already observed its luminosity, its color and its movement through the sky thanks to a telescope from the Asutral European Observatory. This asteroid is unlike any other, it is 400 meters long, has an elongated shape and dark and reddish colors. The asteroid continues its way in the Galaxy at a speed of 95000 km / h.
Detected in October, this strange interstellar visitor could be observed by the largest telescopes in the world, revealing a very elongated shape that surprised astronomers.
On October 19, the Pan-STARRS 1 telescope in Hawaii detects a curious object whose trajectory suggests that it does not come from our solar system. After several days of observation, the news is confirmed. This small body is not a comet from the confines of the solar system since it simply does not orbit around the Sun. It's just passing. It is the first extrasolar visitor we find in our neighborhood. Last week he was dubbed "Oumuamua" by his discoverers, meaning "scout" or "messenger" in Hawaiian. As it is the first "interstellar" asteroid identified, it bears the number 1 and the letter I. This gives 1I / 'Oumuamua in the official nomenclature of the International Astronomical Union invented for the occasion.
European Southern Observatory/ESO/M. Kornmesser
Less than a month after its discovery, the small body is the subject of its first scientific article in the journal Nature on Monday. An extremely short publication time which testifies to the symbolic importance of the discovery, but not only. "There are at least two remarkable things about this object," says Patrick Michel, an asteroid specialist at the Observatoire de la Côte d'Azur. "Its total absence of activity and its hallucinatory form."
The asteroid as it appears on the VLT images, one of the largest telescopes in the world. European Southern Observatory / ESO / K. Meech et al.
Let's start with its shape. It is obviously impossible to draw a portrait as detailed as the artist's view above. Nevertheless, the periodic and significant variations in brightness of the object indicate that it would have a very elongated shape, like a cigar, with a ratio of one in ten between its length and its width. If it were 400 meters long, it would be 40 meters wide, for example.
"It could also be 800m and 80," says Lucie Maquet, astronomer at the Institute of celestial mechanics and calculating ephemeris (IMCCE). "It all depends on how exactly it reflects light." It seems in all cases very dark, similar to coal. Kareen Meech, of the Hawaii Institute of Astronomy, first author of this work, evokes "a complicated, wavy appearance."
A dense and metallic asteroid
"There are elongated objects in the Solar System, but not so extreme," says Patrick Michel. This form is intriguing. It assumes that 'Oumuamua is relatively solid so as not to have disintegrated by the time he was driven out of his own planetary system. In all likelihood, this would have happened quite early in its history. "Its spectrum (the analysis of the light it returns, Ed) is very red and seems to point to a very primitive object when compared to our own solar system," says the specialist. "It would contain a lot of metal and organic matter."
The second surprise comes from its "lack of activity". The observations of the Very Large Telescope of the European Southern Observatory (ESO), located in Chile, like those of the Gemini telescopes, located in Chile and Hawaii, on which the authors of the Nature study are based, show that the asteroid is surrounded by no steam or dust. Its passage near the Sun, four times closer than the Earth's orbit, should have vaporized the residual ice of such an object. "This would indicate that it is an object that has formed near its star, which does not facilitate the ejection scenarios out of its planetary system," said Patrick Michel.
The trajectory of the first interstellar asteroid never detected 1I / 2017 U1 ('Oumuamua). European Southern Observatory / ESO / K. Meech et al.
There is not much time left to observe 'Oumuamua before it disappears from the sky. "Its very high speed, close to 90,000 km / h, does not facilitate its monitoring," says Lucie Maquet. The visitor thus departs inexorably from us. Its exact origin is still unclear. It seems to come from the region of the star Vega, but given its speed, it would have taken 300,000 years to reach us. But the star was not located at this point in the sky at this time ... The most likely hypothesis seems to date that the asteroid has wandered for millions of years in the Milky Way before it do not cross our road by chance.
Oumuamua may well be the first of a long series of interstellar visitors. According to astronomers, an object of this type could cross our Solar System each year. We just could not afford to watch them. Systematic telescopes such as Pan-STARRS would barely reach the sensitivity required to detect them. "Now that we have discovered the very first interstellar rock, we are preparing to observe others!" Enthuses Olivier Hainaut, astronomer at ESO.
F I N .
The first asteroid from another star has a "hallucinating" form.
By Tristan Vey - Updated on 21/11/2017 at 09:02
For the first time, astronomers have discovered an interstellar asteroid. Astronomers will study this asteroid before it leaves the Solar System. They have already observed its luminosity, its color and its movement through the sky thanks to a telescope from the Asutral European Observatory. This asteroid is unlike any other, it is 400 meters long, has an elongated shape and dark and reddish colors. The asteroid continues its way in the Galaxy at a speed of 95000 km / h.
Detected in October, this strange interstellar visitor could be observed by the largest telescopes in the world, revealing a very elongated shape that surprised astronomers.
On October 19, the Pan-STARRS 1 telescope in Hawaii detects a curious object whose trajectory suggests that it does not come from our solar system. After several days of observation, the news is confirmed. This small body is not a comet from the confines of the solar system since it simply does not orbit around the Sun. It's just passing. It is the first extrasolar visitor we find in our neighborhood. Last week he was dubbed "Oumuamua" by his discoverers, meaning "scout" or "messenger" in Hawaiian. As it is the first "interstellar" asteroid identified, it bears the number 1 and the letter I. This gives 1I / 'Oumuamua in the official nomenclature of the International Astronomical Union invented for the occasion.
European Southern Observatory/ESO/M. Kornmesser
Less than a month after its discovery, the small body is the subject of its first scientific article in the journal Nature on Monday. An extremely short publication time which testifies to the symbolic importance of the discovery, but not only. "There are at least two remarkable things about this object," says Patrick Michel, an asteroid specialist at the Observatoire de la Côte d'Azur. "Its total absence of activity and its hallucinatory form."
The asteroid as it appears on the VLT images, one of the largest telescopes in the world. European Southern Observatory / ESO / K. Meech et al.
Let's start with its shape. It is obviously impossible to draw a portrait as detailed as the artist's view above. Nevertheless, the periodic and significant variations in brightness of the object indicate that it would have a very elongated shape, like a cigar, with a ratio of one in ten between its length and its width. If it were 400 meters long, it would be 40 meters wide, for example.
"It could also be 800m and 80," says Lucie Maquet, astronomer at the Institute of celestial mechanics and calculating ephemeris (IMCCE). "It all depends on how exactly it reflects light." It seems in all cases very dark, similar to coal. Kareen Meech, of the Hawaii Institute of Astronomy, first author of this work, evokes "a complicated, wavy appearance."
A dense and metallic asteroid
"There are elongated objects in the Solar System, but not so extreme," says Patrick Michel. This form is intriguing. It assumes that 'Oumuamua is relatively solid so as not to have disintegrated by the time he was driven out of his own planetary system. In all likelihood, this would have happened quite early in its history. "Its spectrum (the analysis of the light it returns, Ed) is very red and seems to point to a very primitive object when compared to our own solar system," says the specialist. "It would contain a lot of metal and organic matter."
The second surprise comes from its "lack of activity". The observations of the Very Large Telescope of the European Southern Observatory (ESO), located in Chile, like those of the Gemini telescopes, located in Chile and Hawaii, on which the authors of the Nature study are based, show that the asteroid is surrounded by no steam or dust. Its passage near the Sun, four times closer than the Earth's orbit, should have vaporized the residual ice of such an object. "This would indicate that it is an object that has formed near its star, which does not facilitate the ejection scenarios out of its planetary system," said Patrick Michel.
The trajectory of the first interstellar asteroid never detected 1I / 2017 U1 ('Oumuamua). European Southern Observatory / ESO / K. Meech et al.
There is not much time left to observe 'Oumuamua before it disappears from the sky. "Its very high speed, close to 90,000 km / h, does not facilitate its monitoring," says Lucie Maquet. The visitor thus departs inexorably from us. Its exact origin is still unclear. It seems to come from the region of the star Vega, but given its speed, it would have taken 300,000 years to reach us. But the star was not located at this point in the sky at this time ... The most likely hypothesis seems to date that the asteroid has wandered for millions of years in the Milky Way before it do not cross our road by chance.
Oumuamua may well be the first of a long series of interstellar visitors. According to astronomers, an object of this type could cross our Solar System each year. We just could not afford to watch them. Systematic telescopes such as Pan-STARRS would barely reach the sensitivity required to detect them. "Now that we have discovered the very first interstellar rock, we are preparing to observe others!" Enthuses Olivier Hainaut, astronomer at ESO.
F I N .
