Post by Andrei Tchentchik on Jun 22, 2019 14:33:04 GMT 2
(.#206).- A new planet discovered in a ‘’habitable zone’’.
A new planet discovered in a ‘’habitable’’ zone.
By Tristan Vey - Updated on 25/08/2016 at 11:19
Artist's impression of the surface of the planet Proxima Centauri b. Credit: ESO / M. Kornmesser / ESO / M. Kornmesser
This rocky world orbiting our nearest neighbor, Proxima Centauri, is located in an area compatible with the existence of liquid water.
Sci-fi enthusiasts no longer believed in it: a planet is really spinning around the nearest star, Proxima Centauri. Which makes it de facto the closest exoplanet of the Earth and therefore the best candidate for a putative extrasolar exploration mission. Better, it is probably rocky and located in the zone "habitable" of its star, that is to say at a distance compatible with the existence of liquid water on its surface, announces today an international team in the journal Nature. Caution remains in place. This does not mean that the water is flowing on its surface, much less that little green men floundering in it. Let us remember that Venus and Mars, as well as the Moon, are also located in the "habitable" zone around our Sun. However, they do not harbor rivers or oceans. As for life in any form whatsoever ...
But it is not forbidden to dream a little and it could be quite different on Proxima Centauri b - the name of our new neighbor. "It is impossible to give a formal answer to this question for the moment," explains Franck Selsis, head of the team [exo] Terres at the astrophysics laboratory in Bordeaux. In several companion papers currently being published, researchers around the world have begun to formulate hypotheses about the possible landscape on the surface of the newcomer.
"Not a twin of the Earth"
It is necessary to be content with conjectures. To this day, everything is imaginable: it could as well shelter gigantic oceans as be completely devoid of atmosphere. Be completely frozen or hot as an oven. Although it is closest to us astronomically, Proxima Centauri b remains a little more than four light years away, a little less than 40,000 billion kilometers. It was detected only by the gravitational influence it exerted on its star, a red dwarf almost ten times less massive than our Sun and 1000 times less luminous. "When a planet revolves around its star, it causes it to oscillate very slightly back and forth, which changes its color by Doppler effect," explains Julien Morin, researcher at the Universe and Particle Laboratory of Montpellier, co-author of the discovery.
It is these very slight changes in the red of Proxima Centauri that betrayed the presence of the small planet after more than two months of daily observations in early 2016 with the telescope of Silla (3.6 meters in diameter), located in Chile and property of the European Southern Observatory (ESO). "If it had not been previously detected despite its proximity, it is because Proxima du Centaure, like many red dwarfs, is a very active star that can produce these color changes" naturally ", details Julien Morin. It was not easy to make sure that was not the case. "
If you had your feet on the surface of the planet, you would see a red sun almost three times bigger than ours, accompanied by two other small suns.
This method of detection does not allow to know the radius of the planet but only a minimum mass. In this case, 1.3 times that of the Earth. The planet could also weigh up to several land masses. Despite this uncertainty, it is likely to remain rocky. Proxima Centauri b is also 20 times closer to its star than the Earth of the Sun. If you had your feet on the surface, you would see a red sun nearly three times bigger than ours, accompanied by two other small suns, the Alpha Centauri stars a and b that accompany our nearest neighbor. The planet must also undergo tidal forces (caused by the gravitational attraction of its star) considerable. It is also probable that it is for this reason "forced" to always present its same face to its star (in the same way that the Moon presents the Earth always the same side). This would induce very particular constraints on its possible atmosphere.
"Proxima Centauri b will not be a twin of the Earth, warns Franck Selsis. His sun too is very different. It emits many more extreme X-rays and UV rays. "The whole question is whether this radiation and the wind of very intense particles emitted by the red dwarf have or have not fully blown its atmosphere. "If this is the case, the difference in temperature between the illuminated and the dark side may be large enough for the future American space telescope JWST to detect," said Martin Turbet, a researcher at the Laboratory of Dynamic Meteorology, Paris.
In the case, more favorable to the presence of liquid water, where the planet would still have an atmosphere, it will be necessary to wait for the E-ELT (European Extremely Large Telescope) under construction in Chile, to study it. Scheduled for 2024, this 39 meter behemoth will be the only one able to distinguish the small planet in the light of its star. It should then be possible to detect its possible atmosphere and determine its composition. With this hope a little crazy: that there are traces of the first extraterrestrial life.
If you leave now, you will arrive in the year 21 016 ...
By Cyrille Vanlerberghe
Proxima Centauri may be the closest star to the Sun, 4.2 light years away, the potentially habitable planet that revolves around is still inaccessible. To have an order of magnitude of the colossal distances at stake, it would take 19,000 years to reach the destination with the fastest object ever sent by a rocket, the probe Helios 2 of NASA, which reached a speed of 240,000 km / h. We must go faster.
With a nuclear propulsion, under study for decades to shorten the trip to Mars, the trip to Proxima would only last "1000". Still too long? We must then turn to even more futuristic technologies, close to science fiction. The thermonuclear fusion, which one seeks to domesticate for the Iter reactor in the south of France, could in theory make it possible to reach 12% of the speed of the light. The trip to Proxima would then last 36 years.
Russian billionaire Yuri Milner believes, however, that it will be possible to send a tiny automatic probe (mass: 1 g) to Proxima as early as 2035, propelling it with an extremely powerful laser shot. At 20% of the speed of light, the trip would only take 20 years. But the huge acceleration at the start makes the technology unthinkable for an inhabited flight.
F I N .
A new planet discovered in a ‘’habitable’’ zone.
By Tristan Vey - Updated on 25/08/2016 at 11:19
Artist's impression of the surface of the planet Proxima Centauri b. Credit: ESO / M. Kornmesser / ESO / M. Kornmesser
This rocky world orbiting our nearest neighbor, Proxima Centauri, is located in an area compatible with the existence of liquid water.
Sci-fi enthusiasts no longer believed in it: a planet is really spinning around the nearest star, Proxima Centauri. Which makes it de facto the closest exoplanet of the Earth and therefore the best candidate for a putative extrasolar exploration mission. Better, it is probably rocky and located in the zone "habitable" of its star, that is to say at a distance compatible with the existence of liquid water on its surface, announces today an international team in the journal Nature. Caution remains in place. This does not mean that the water is flowing on its surface, much less that little green men floundering in it. Let us remember that Venus and Mars, as well as the Moon, are also located in the "habitable" zone around our Sun. However, they do not harbor rivers or oceans. As for life in any form whatsoever ...
But it is not forbidden to dream a little and it could be quite different on Proxima Centauri b - the name of our new neighbor. "It is impossible to give a formal answer to this question for the moment," explains Franck Selsis, head of the team [exo] Terres at the astrophysics laboratory in Bordeaux. In several companion papers currently being published, researchers around the world have begun to formulate hypotheses about the possible landscape on the surface of the newcomer.
"Not a twin of the Earth"
It is necessary to be content with conjectures. To this day, everything is imaginable: it could as well shelter gigantic oceans as be completely devoid of atmosphere. Be completely frozen or hot as an oven. Although it is closest to us astronomically, Proxima Centauri b remains a little more than four light years away, a little less than 40,000 billion kilometers. It was detected only by the gravitational influence it exerted on its star, a red dwarf almost ten times less massive than our Sun and 1000 times less luminous. "When a planet revolves around its star, it causes it to oscillate very slightly back and forth, which changes its color by Doppler effect," explains Julien Morin, researcher at the Universe and Particle Laboratory of Montpellier, co-author of the discovery.
It is these very slight changes in the red of Proxima Centauri that betrayed the presence of the small planet after more than two months of daily observations in early 2016 with the telescope of Silla (3.6 meters in diameter), located in Chile and property of the European Southern Observatory (ESO). "If it had not been previously detected despite its proximity, it is because Proxima du Centaure, like many red dwarfs, is a very active star that can produce these color changes" naturally ", details Julien Morin. It was not easy to make sure that was not the case. "
If you had your feet on the surface of the planet, you would see a red sun almost three times bigger than ours, accompanied by two other small suns.
This method of detection does not allow to know the radius of the planet but only a minimum mass. In this case, 1.3 times that of the Earth. The planet could also weigh up to several land masses. Despite this uncertainty, it is likely to remain rocky. Proxima Centauri b is also 20 times closer to its star than the Earth of the Sun. If you had your feet on the surface, you would see a red sun nearly three times bigger than ours, accompanied by two other small suns, the Alpha Centauri stars a and b that accompany our nearest neighbor. The planet must also undergo tidal forces (caused by the gravitational attraction of its star) considerable. It is also probable that it is for this reason "forced" to always present its same face to its star (in the same way that the Moon presents the Earth always the same side). This would induce very particular constraints on its possible atmosphere.
"Proxima Centauri b will not be a twin of the Earth, warns Franck Selsis. His sun too is very different. It emits many more extreme X-rays and UV rays. "The whole question is whether this radiation and the wind of very intense particles emitted by the red dwarf have or have not fully blown its atmosphere. "If this is the case, the difference in temperature between the illuminated and the dark side may be large enough for the future American space telescope JWST to detect," said Martin Turbet, a researcher at the Laboratory of Dynamic Meteorology, Paris.
In the case, more favorable to the presence of liquid water, where the planet would still have an atmosphere, it will be necessary to wait for the E-ELT (European Extremely Large Telescope) under construction in Chile, to study it. Scheduled for 2024, this 39 meter behemoth will be the only one able to distinguish the small planet in the light of its star. It should then be possible to detect its possible atmosphere and determine its composition. With this hope a little crazy: that there are traces of the first extraterrestrial life.
If you leave now, you will arrive in the year 21 016 ...
By Cyrille Vanlerberghe
Proxima Centauri may be the closest star to the Sun, 4.2 light years away, the potentially habitable planet that revolves around is still inaccessible. To have an order of magnitude of the colossal distances at stake, it would take 19,000 years to reach the destination with the fastest object ever sent by a rocket, the probe Helios 2 of NASA, which reached a speed of 240,000 km / h. We must go faster.
With a nuclear propulsion, under study for decades to shorten the trip to Mars, the trip to Proxima would only last "1000". Still too long? We must then turn to even more futuristic technologies, close to science fiction. The thermonuclear fusion, which one seeks to domesticate for the Iter reactor in the south of France, could in theory make it possible to reach 12% of the speed of the light. The trip to Proxima would then last 36 years.
Russian billionaire Yuri Milner believes, however, that it will be possible to send a tiny automatic probe (mass: 1 g) to Proxima as early as 2035, propelling it with an extremely powerful laser shot. At 20% of the speed of light, the trip would only take 20 years. But the huge acceleration at the start makes the technology unthinkable for an inhabited flight.
F I N .
