Post by Andrei Tchentchik on Jun 22, 2019 14:43:57 GMT 2
(.#208).- A super-Earth around the star of Barnard, closer neighbors.
A super-Earth around the Barnard star, one of our closest neighbours.
By Tristan Vey - Updated on 14/11/2018 at 19:21
Artist's impression of the surface of the exoplanet potentially orbiting the Barnard star. European Southern Observatory / ESO / M. Kornmesser.
This planet would weigh at least three times the mass of the Earth. If its existence is confirmed, it would be the second exoplanet closest to the Earth, after Proxima b.
Barnard's star is only six light years away from us. The door next to the scale of the universe. It is our closest neighbor in the galaxy after the Alpha Centauri A, B and C stars (the latter being more familiarly known as Centaur's Proxima). Astronomers have been searching for years to uncover potential planets orbiting this red dwarf, six times less massive than the Sun.
In a new study published in Nature this Wednesday, an international team led by Ignasi Ribas of the Institute of Space Sciences in Spain, provides the first solid evidence of the existence of a planet orbiting our planet. neighbor. This would make it the second closest exoplanet to Earth, after Proxima b (orbiting Proxima Centauri) to this day.
This newcomer would be potentially rocky (although it also remains to be confirmed) and weigh a minimum of three times the mass of the Earth. Which would put it in the category of "super-lands". It would be two times closer to its star than the Earth of the Sun (which would correspond to the distance that separates Mercury from our star) and would take a little more than 200 days to complete a revolution. Since Barnard's star is much less hot than the Sun, this places this planet just beyond the "ice line", ie in a zone so cold that the presence of liquid water would be, at best, highly improbable.
The location of Barnard's star in relation to the Sun and its nearest neighbors. IEEC / Science-Wave - Guillem Ramisa.
It took researchers 20 years of data, collected from eight different instruments, to reach these preliminary conclusions. "This is a very nice result," says Magali Deleuil, exoplanet specialist at the Laboratory of Astrophysics in Marseille. "In a media world where everything goes very fast, you can sometimes have the illusion that things happen almost easily. On the contrary, it reminds us that these objects remain very difficult to detect. The demonstration is encouraging, although it still needs to be confirmed. We have had cases of false detections in the past. The authors are right to remain cautious. "
For the moment, researchers are only evoking a "candidate" planet despite the considerable data set collected. "It's about how far we are at the boundaries of instrument detection capabilities," says Jean-François Donati, astronomer at IRAP in Toulouse, and scientific leader of the brand new SPIRou instrument installed on the Canada-France telescope. -Hawaii, who could confirm this detection one day. "Barnard's star is one of the things we're studying, but we'll need at least two years of observations before we can decide one way or the other."
Artist's impression of the candidate planet orbiting Barnard's star. IEEC / Science-Wave - Guillem Ramisa.
In the meantime, the Gaia satellite data could also be used in 2020. This European space observatory makes extremely precise astrometric measurements and should be able to detect the small lateral movements of a star caused by the ballet of the planets. turn him around. A technique radically different from the one used today, called the "radial velocity method". The latter consists in detecting the movements of a star back and forth, again provoked by the attraction of the planets which revolve around it. Astronomers use the Doppler effect for this: the light emitted by the star is "stretched" when it goes away - it blushes - then it is "compressed" when it gets closer - it turns blue.
A prime target for future telescopes
As for the method of transits, which is to detect micro-eclipses caused by the passage of the planet in front of its star, it is unlikely to work in this case. "It is not at all obvious that the planet orbits in the right plane compared to us," recalls Alexandre Santerne, assistant astronomer at the Laboratory of Astrophysics of Marseille. The American Kepler satellite, which discovered by this method a large majority of the 4000 exoplanets inventoried to date, did not observe this star anyway. But his replacement, TESS, American too will cover him all the sky. With a little - a lot - of luck ...
If astronomers are equally interested in Barnard's star, it is because the stars close to us are not legion. And the planets no longer blow. However, the development of new generations of instruments, be it the future American space telescope JWST or the gigantic European ELT terrestrial telescope, under construction in Chile, should allow to know much more about these worlds by directly analyzing the light that they reflect. "This new super-Earth is a billion times less luminous than its star, so it should be difficult, but it will make it an interesting target in the years and decades to come," promises François Bouchy, specialist of the detection and characterization of exoplanets at the University of Geneva.
F I N .
A super-Earth around the Barnard star, one of our closest neighbours.
By Tristan Vey - Updated on 14/11/2018 at 19:21
Artist's impression of the surface of the exoplanet potentially orbiting the Barnard star. European Southern Observatory / ESO / M. Kornmesser.
This planet would weigh at least three times the mass of the Earth. If its existence is confirmed, it would be the second exoplanet closest to the Earth, after Proxima b.
Barnard's star is only six light years away from us. The door next to the scale of the universe. It is our closest neighbor in the galaxy after the Alpha Centauri A, B and C stars (the latter being more familiarly known as Centaur's Proxima). Astronomers have been searching for years to uncover potential planets orbiting this red dwarf, six times less massive than the Sun.
In a new study published in Nature this Wednesday, an international team led by Ignasi Ribas of the Institute of Space Sciences in Spain, provides the first solid evidence of the existence of a planet orbiting our planet. neighbor. This would make it the second closest exoplanet to Earth, after Proxima b (orbiting Proxima Centauri) to this day.
This newcomer would be potentially rocky (although it also remains to be confirmed) and weigh a minimum of three times the mass of the Earth. Which would put it in the category of "super-lands". It would be two times closer to its star than the Earth of the Sun (which would correspond to the distance that separates Mercury from our star) and would take a little more than 200 days to complete a revolution. Since Barnard's star is much less hot than the Sun, this places this planet just beyond the "ice line", ie in a zone so cold that the presence of liquid water would be, at best, highly improbable.
The location of Barnard's star in relation to the Sun and its nearest neighbors. IEEC / Science-Wave - Guillem Ramisa.
It took researchers 20 years of data, collected from eight different instruments, to reach these preliminary conclusions. "This is a very nice result," says Magali Deleuil, exoplanet specialist at the Laboratory of Astrophysics in Marseille. "In a media world where everything goes very fast, you can sometimes have the illusion that things happen almost easily. On the contrary, it reminds us that these objects remain very difficult to detect. The demonstration is encouraging, although it still needs to be confirmed. We have had cases of false detections in the past. The authors are right to remain cautious. "
For the moment, researchers are only evoking a "candidate" planet despite the considerable data set collected. "It's about how far we are at the boundaries of instrument detection capabilities," says Jean-François Donati, astronomer at IRAP in Toulouse, and scientific leader of the brand new SPIRou instrument installed on the Canada-France telescope. -Hawaii, who could confirm this detection one day. "Barnard's star is one of the things we're studying, but we'll need at least two years of observations before we can decide one way or the other."
Artist's impression of the candidate planet orbiting Barnard's star. IEEC / Science-Wave - Guillem Ramisa.
In the meantime, the Gaia satellite data could also be used in 2020. This European space observatory makes extremely precise astrometric measurements and should be able to detect the small lateral movements of a star caused by the ballet of the planets. turn him around. A technique radically different from the one used today, called the "radial velocity method". The latter consists in detecting the movements of a star back and forth, again provoked by the attraction of the planets which revolve around it. Astronomers use the Doppler effect for this: the light emitted by the star is "stretched" when it goes away - it blushes - then it is "compressed" when it gets closer - it turns blue.
A prime target for future telescopes
As for the method of transits, which is to detect micro-eclipses caused by the passage of the planet in front of its star, it is unlikely to work in this case. "It is not at all obvious that the planet orbits in the right plane compared to us," recalls Alexandre Santerne, assistant astronomer at the Laboratory of Astrophysics of Marseille. The American Kepler satellite, which discovered by this method a large majority of the 4000 exoplanets inventoried to date, did not observe this star anyway. But his replacement, TESS, American too will cover him all the sky. With a little - a lot - of luck ...
If astronomers are equally interested in Barnard's star, it is because the stars close to us are not legion. And the planets no longer blow. However, the development of new generations of instruments, be it the future American space telescope JWST or the gigantic European ELT terrestrial telescope, under construction in Chile, should allow to know much more about these worlds by directly analyzing the light that they reflect. "This new super-Earth is a billion times less luminous than its star, so it should be difficult, but it will make it an interesting target in the years and decades to come," promises François Bouchy, specialist of the detection and characterization of exoplanets at the University of Geneva.
F I N .
