Post by Andrei Tchentchik on Sept 3, 2020 15:26:46 GMT 2
(.#510).- We now know what passes in front of the star KIC 8462852.
We finally know what hides "the Tabby star", the most mysterious of the galaxy.
03/01/2018 18:30
By Grégory Rozières
Scientists and fans of aliens have been wondering for over two years what is going on in front of KIC 8462852.
NASA / JPL-CALTECH
We finally know what hides
SPACE - A little over two years ago, a mysterious star attracted the attention of a few scientists, then the media. KIC 8462852 was indeed very strange: it seemed that a gigantic object was passing through the space in front of it, covering the equivalent of a fifth of its surface when we observed it.
The classic explanations evoked comets, or even dust. But none of them fit perfectly with these bizarre observations. "Tabby's star", named after the astrophysicist who wrote the first article about it, Tabetha Boyajian, was the most mysterious in the galaxy.
Logically, this state of affairs ended up causing some astrophysicists to wonder if this oddity was not due to an extraterrestrial mega structure. This has attracted the attention of many curious people around the world, in the scientific community and elsewhere.
More than two years later, a study has just brought the answer that everyone expected. Disappointing, for all dreamers: it is indeed a gigantic amount of tiny dust that blocks the light of the star of Tabby, specify the more than 200 authors of the article, published this Wednesday, January 3 in the journal Astrophysical Journal Letters .
Citizen observation
Before looking at the results published by the researchers, we must understand why it took so long before having a definitive answer on what hid the view from the Tabby star, located about 1500 light years away. of the earth.
At the time, it was impossible to decide in the state. These sudden light shifts were recorded between 2011 and 2013 by the Kepler space telescope (which allowed us to identify thousands of planets outside the solar system). And if many theories, contradictory, have been developed, new observations were needed to unravel this mystery.
Tabetha Boyajian and her colleagues therefore raised 100,000 euros on Kickstarter to scrutinize this strange star daily, awaiting a sign, an anomaly.
And this is precisely what happened last May. As predicted by scientists' calculations, the Tabby star was again obscured. To realize this, it is "enough" for a telescope to record the light intensity of the star. If the brightness drops, something has happened on the path between the star and the Earth. Like during an eclipse. It is with this technique that we identify exo-planets around distant stars.
A matter of color
And when it happened again in May 2017, the astrophysicists were ready. Very quickly, a dozen different telescopes turned their lens on KIC 8462852. But by not observing the same thing: each objective works on a very specific wavelength, a different "color".
For months, 200 researchers have therefore analyzed all this data collected to try to understand what could possibly go past the star of Tabby.
The conclusion is therefore that of tiny dust, 100 times smaller than the diameter of a hair. Indeed, all the data observed in the different wavelengths stick with this analysis, specify the authors.
"If a solid, opaque object, like a mega structure passed in front of the star, it would block light in all colors in the same way. The opposite is observed," Tabetha Boyajian told National Geographic.
Many other mysteries to unravel
If the thesis of an extraterrestrial megastructure is definitively buried, the star of Tabby has not yet revealed all its secrets. Thus, specify the researchers, the dust solution "still challenges our creativity to develop a unified theory allowing to explain all the observations".
Indeed, if it is now clear that it is billions of tiny grains of matter that block the light of KIC 8462852, remains to understand where they come from and where they are going. Certain theories evoke objects, such as exo-comets, which would revolve around the star of Tabby on a very eccentric plane. Others wonder if it was not due to a gigantic planet collision, or even if the star would not have simply eaten one.
Hard to say at the moment. Especially since each drop in brightness is quite different from the others. Moreover, the four recorded in 2017 did not block more than 2.5% of the brightness of the Tabby star. Where as in 2013, 20% of its light was masked.
To learn more and solve the last mysteries of KIC 8462852, you will have to continue to observe it and be patient. If the cloud of dust passes well around every 750 days in front of the star, we should observe something in June 2019.
But again, nothing is less certain: new theories wonder if the event would not take place every 1500 days. The Tabby star should therefore keep its mysteries for a while longer.
F I N .
We finally know what hides "the Tabby star", the most mysterious of the galaxy.
03/01/2018 18:30
By Grégory Rozières
Scientists and fans of aliens have been wondering for over two years what is going on in front of KIC 8462852.
NASA / JPL-CALTECH
We finally know what hides
SPACE - A little over two years ago, a mysterious star attracted the attention of a few scientists, then the media. KIC 8462852 was indeed very strange: it seemed that a gigantic object was passing through the space in front of it, covering the equivalent of a fifth of its surface when we observed it.
The classic explanations evoked comets, or even dust. But none of them fit perfectly with these bizarre observations. "Tabby's star", named after the astrophysicist who wrote the first article about it, Tabetha Boyajian, was the most mysterious in the galaxy.
Logically, this state of affairs ended up causing some astrophysicists to wonder if this oddity was not due to an extraterrestrial mega structure. This has attracted the attention of many curious people around the world, in the scientific community and elsewhere.
More than two years later, a study has just brought the answer that everyone expected. Disappointing, for all dreamers: it is indeed a gigantic amount of tiny dust that blocks the light of the star of Tabby, specify the more than 200 authors of the article, published this Wednesday, January 3 in the journal Astrophysical Journal Letters .
Citizen observation
Before looking at the results published by the researchers, we must understand why it took so long before having a definitive answer on what hid the view from the Tabby star, located about 1500 light years away. of the earth.
At the time, it was impossible to decide in the state. These sudden light shifts were recorded between 2011 and 2013 by the Kepler space telescope (which allowed us to identify thousands of planets outside the solar system). And if many theories, contradictory, have been developed, new observations were needed to unravel this mystery.
Tabetha Boyajian and her colleagues therefore raised 100,000 euros on Kickstarter to scrutinize this strange star daily, awaiting a sign, an anomaly.
And this is precisely what happened last May. As predicted by scientists' calculations, the Tabby star was again obscured. To realize this, it is "enough" for a telescope to record the light intensity of the star. If the brightness drops, something has happened on the path between the star and the Earth. Like during an eclipse. It is with this technique that we identify exo-planets around distant stars.
A matter of color
And when it happened again in May 2017, the astrophysicists were ready. Very quickly, a dozen different telescopes turned their lens on KIC 8462852. But by not observing the same thing: each objective works on a very specific wavelength, a different "color".
For months, 200 researchers have therefore analyzed all this data collected to try to understand what could possibly go past the star of Tabby.
The conclusion is therefore that of tiny dust, 100 times smaller than the diameter of a hair. Indeed, all the data observed in the different wavelengths stick with this analysis, specify the authors.
"If a solid, opaque object, like a mega structure passed in front of the star, it would block light in all colors in the same way. The opposite is observed," Tabetha Boyajian told National Geographic.
Many other mysteries to unravel
If the thesis of an extraterrestrial megastructure is definitively buried, the star of Tabby has not yet revealed all its secrets. Thus, specify the researchers, the dust solution "still challenges our creativity to develop a unified theory allowing to explain all the observations".
Indeed, if it is now clear that it is billions of tiny grains of matter that block the light of KIC 8462852, remains to understand where they come from and where they are going. Certain theories evoke objects, such as exo-comets, which would revolve around the star of Tabby on a very eccentric plane. Others wonder if it was not due to a gigantic planet collision, or even if the star would not have simply eaten one.
Hard to say at the moment. Especially since each drop in brightness is quite different from the others. Moreover, the four recorded in 2017 did not block more than 2.5% of the brightness of the Tabby star. Where as in 2013, 20% of its light was masked.
To learn more and solve the last mysteries of KIC 8462852, you will have to continue to observe it and be patient. If the cloud of dust passes well around every 750 days in front of the star, we should observe something in June 2019.
But again, nothing is less certain: new theories wonder if the event would not take place every 1500 days. The Tabby star should therefore keep its mysteries for a while longer.
F I N .
