[ad_1]
Of the nearly one million Kepler telescope stars, few have attracted as much attention as KIC 8462852, also known as the Boyajian star. New research suggests that its sporadic gradation is not caused by comet swarms or extraterrestrial megastructure, but rather by an abandoned exomoon trapped in annihilation.
The Boyajian star, also known as Tabby Star, was discovered nearly 130 years ago, but its unusual gradation behavior was first detected in 2015 by Tabetha Boyajian, an astrophysicist from the University of California. State of Louisiana State, whose star now bears the name.
Located about 1500 light-years away from Earth, this star is otherwise normal, except for its intermittent attenuations. The brightness of the star has decreased up to 22%, and these brightness changes can last a few days or weeks. Archival data collected by LSU astronomer Bradley Schaefer suggests that the Boyajian star is becoming less luminous, with a 14% decrease in brightness between 1890 and 1989.
These observations gave rise to a multitude of possible explanations, including a swarm of comets, an irregular band of dust, the remains of a freshly destroyed planet and a deformed star. The sightings were so strange that astronomer Jason Wright of Penn State had proposed the presence of an extraterrestrial megastructure.
A team of astronomers from Columbia University offered another possible explanation. It's actually pretty wild, although not so wild that it's not taken seriously by outside experts.
In the new article, published in the Monthly Notices of the Royal Astronomical Society, astronomers Brian Metzger, Miguel Martinez and Nicholas Stone present a scenario in which an orphan moon, thrown by her damned mother planet, slows her melting when she gets pounded. radiation from its host host. Fragments of the disintegrating exomoon regularly leak into space, creating a dusty ring around the Boyajian star. Seen from the Earth, this ring causes the blocking of starlight.
"This document is an important contribution to the subject. It does detailed work analyzing much of the dynamics of such a chaotic system, and the results look promising for this theory, "said Boyajian, who did not participate in the discussions. new study, in an email to Gizmodo.
Kevel Stassun astronomer of Vanderbilt University also appreciated the new study, claiming that the proposed explanation for mitigation was "plausible and interesting," though slightly speculative.
"Everything, everywhere, ends up dying. One of the great legacies of the Kepler Space Telescope is that it has revealed the amazing variety of ways used by the content of other solar systems – planets, moons, comets, and so on. – the disappearance of the experience in the hands of the stars that they orbit, "said Stassun, who was not involved in the new research, in an email to Gizmodo. "This new study adds an additional chapter to the growing body of astronomers on Grimm's stories of how solar systems are achieving their critical goal."
As Metzger and his colleagues explain in their new paper, the beginning of the picky ending begins with an exoplanet and its associated exomoon, both in orbit around Boyajian's Star, and by an unfortunate encounter with the forces of gravitation intense exoplanet by a massive exoplanet inhabiting the same solar system. The resulting gravitational disturbance caused the mother planet to enter an extremely eccentric orbit that placed it on a collision course with the host star. At the same time, the interaction also resulted in "tidal detachment," as researchers in the study described it, according to which the Moon was permanently separated from its mother planet.
By conducting computer simulations of this scenario, researchers at Columbia University have shown that in cases involving exoplanets breaking their host stars, most exomoons would join their parent planets in a show of apocalyptic solidarity. But the models also showed that about 10% of orphaned moons would survive their mother planet, staying in orbit around the host star but at an uncomfortable proximity. As a result, and as the researchers assume in this case, an intense stellar radiation from Boyajian's Star removes material from the surface of the orphaned exomoon, resulting in the aforementioned dust ring. According to the new study, it will take some millions of years for the exoem to disappear completely.
Similar to the way comets evaporate in our own solar system, the exomoon releases a solid material in the form of small and large particles, Metzger told Gizmodo in an email.
"The small particles – those with a diameter of less than one micron – are very opaque, but feel strong radiation pressure from the star because they are light," Metzger said. "Although potentially forming a temporary" cloud "in the immediate vicinity of the moon, possibly contributing to the" hollow "observed when passing in front of the star," the cloud of dust "will eventually be removed from the star system," That is, "blown by the radiation pressure and therefore, will not stay long enough to cause long-term dimming."
At the same time, Metzger said that larger particles would not be subjected to strong radiation pressure, which would leave them in orbit around the star. This is important because large particles will slowly be driven to the star over hundreds, if not thousands of years, he said. The accumulation of these large particles will create a ring-shaped disk, very similar to the rings of Saturn, which can slowly block parts of the star's light on a longer time scale, Metzger explained. .
According to Metzger, these details are important, but the "potentially more interesting" aspect of his team's research was to propose a natural mechanism for explaining the observed lows, ie the capacity of an orphaned exomoon. deposit rich materials in orbit around a star.
Schaefer explained to Gizmodo in an email that what is interesting in this article is that it provides the "first reasonable model" to explain the lows in the star, while previous attempts to explain the anomaly were not "astrophysically reasonable".
"For the most striking example," the idea of the comet "could have perhaps created such hollows, but it was very improbable to have deep troughs ", so many" super-super-sized comets "were necessary for the proper functioning of the theory, besides no good theory explained why a single star on a million suddenly exposed these dips, said Schaefer, who has not participated in the new research.
"Now, for the first time, we have a model that does not just claim an improbable assertion," Schaefer told Gizmodo. The new document "provides a plausible mechanism for obtaining several troughs at the same time, as well as a plausible mechanism for obtaining enough dust during a recent singular event (for each dive), and explains why the troughs on the Boyajian star should be: very rare, but not so rare that it is probably never seen 'in the many stars observed by the Kepler Space Telescope. "The new document provides detailed and realistic calculations in support of their plausibility arguments."
Apart from this eulogy, it should be emphasized that the speculations made in the document are only speculations. Yes, the "natural mechanism" proposed by the authors is corroborated by computer models and mathematics, but additional evidence is needed to reinforce the argument, such as the visual or spectrographic observations of the dusty disk itself. The additional evidence will have to take the form of more empirical observations, both at Boyajian's Star and elsewhere.
Our galaxy is bursting with habitable examinations
There are eight planets in our solar system (sorry Pluto), but collectively, these planets harbor …
Read more
The good news is that this phenomenon, though rare, would not be so rare that we should not see it spawning around another star. And although we do not yet have to prove definitively the existence of exomoons outside our solar system, astronomers have good reason to believe that our galaxy abounds. But since the Boyajian Star is (apparently) one in a million, we will have to be patient.
[ad_2]
Source link