Fourteen years ago, NASA caused a stir when it revealed certain analysis results of observations from the defunct Spitzer telescope for observing in the infrared range. As Futura explained in the following article, Spitzer had found indirect evidence for the existence of rocky planets associated with binary star systems. Since binary stars represent the majority in the Milky Way, we might conclude that at least some could be habitable and that some form of intelligent life could contemplate double sunsets on these planets, like in the mythical Star Wars scenes with Luke Skywalker on the planet Tatooine.
The number of known exoplanets in the Milky Way has increased significantly since then, and some of them are actually part of a binary star system. If the formation of planets indeed seems to be the rule around the stars, this was not obvious in binary stars, as we might assume that the attractive forces of the two stars could cause phenomena not conducive to the formation or survival of planets in particular due to collisions caused by the manifestation of chaos theory in celestial mechanics.
From this perspective, we could ask questions about the habitability of terrestrial exoplanets around the stars. Wouldn't fluctuations in the orbits and rotations of these exoplanets often lead to drastic and chaotic changes in climate, climate, or habitability, for example turning a formerly habitable planet into an ice planet and killing all life?
Researchers working with data from NASA's Transiting Exoplanet Survey Satellite (Tess) discovered the mission's first circumbinary planet, a planet orbiting two stars, several years ago. The planet, called TOI 1338b, is about 6.9 times larger than Earth, or about the size of Neptune and Saturn. It is located in a system 1,300 light-years away in the constellation Pictor. The system's stars form an eclipsing binary star system, which occurs when companion stars orbit each other in our plane of view. One is about 10% more massive than our Sun, while the other is colder, dimmer and only a third of the Sun's mass. TOI 1338b's transits are irregular – every 93 to 95 days – and vary in depth and duration due to the orbital motion of its stars. To get a reasonably accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then click on “Subtitles” and finally “Auto-translate”. Select “French”. © NASA Goddard Space Flight Center
Do planetary systems like to move toward an ordered configuration?
A recent paper published in the Astronomical Journal and freely available on arXiv by Malena Rice, assistant professor of astronomy at the Yale School of Arts and Sciences and lead author of the new study, and her colleagues Konstantin Gerbig, a graduate student in astrophysics at Yale, and Andrew Vanderburg, assistant professor of Physics at MIT (Massachusetts Institute of Technology) is interesting for exobiology in this respect.
As the Yale communication for publication in the Astronomical Journal explains, according to the authors, there are more climate-friendly planets in binary star systems than previously thought. That's why Malena Rice says: “We show for the first time that there is an unexpected collection of systems in which everything is coordinated.” The planets rotate in exactly the same direction as the first star, and the second star orbits this system same level as the planets.
This could suggest that planetary systems like to move toward an ordered configuration.
This is also good news for the life that forms in these systems. Star companions that are aligned differently can wreak havoc on planetary systems, disrupting them or warming the planets over time. »
The research team discovered that nine of the 40 systems examined (specifically using data from ESAESA's Gaiasatellite Gaia satellite) had “perfect” alignment. For those interested in what an intelligent life form on Tatooine with a temperate climate would actually see, Yale's statement on the subject is particularly clear: “At certain times of the year it was continuously daytime, and a star illuminated one side of the planet. while the other star illuminated the other half of the planet. But that sunlight wouldn't always be hot because one of the stars would be much further away.
At other times of the year, both suns illuminated the same side of the planet, with one appearing much larger than the other. »
Are we alone in the Universe? Maybe you've asked yourself the question before… We find answers in films, literature or science fiction comics and our imaginations are populated by alien creatures! But what does science say about this? The AstrobioEducation website invites you to discover exobiology, an interdisciplinary science whose aim is to study the origin of life and its research elsewhere in the universe. On an educational journey divided into 12 stages, researchers from various disciplines will help you understand how science works to answer the fascinating questions about the origin of life and its research elsewhere than on Earth. © French Society of Exobiology
In the video: Double sunsets would be the rule in the universe
Article by Laurent SaccoLaurent Sacco, published on April 13, 2007
The universe is definitely full of surprises. According to studies using NASA's Spitzer satellite, double sunsets like those contemplated by Luke Skywalker in Star Wars are not the exception, but rather the rule!
The Copernican Revolution is not dead, it is very much alive! Having moved our planet from the center of the solar system and reduced our star to the rank of a dwarf star, a common dwarf star in the galaxy, everything seems to indicate that a planetary system will preferably form around a binary star system. We might already suspect this, since binary stars represent the majority in the cosmos, but were the laws of celestial mechanics favorable for the formation of planetary systems in such an environment?
To answer this question, Spitzer's infrared capabilities were required. We can't detect Earth-like planets yet, CorotCorot is expected to do so soon, but we can detect disks of dust around stars. You could even almost say that Spitzer was designed specifically for this purpose.
The strategy was therefore to look for dust disks, remnants of accretion disks, planet-forming accretion disks around the binary systems (see the artist's illustration below). The presence of such disks should be related to the existence of an asteroid belt in which collisions and fragmentation still occur. It is the results of this research that astrophysicists such as John Stansberry, David Trilling and G. Bryden published in a joint article in the Astrophysical Journal.
These refer to the study of 69 binary systems between 50 and 200 light years around the Sun, with stars slightly younger and more massive than ours. We already knew that certain binary stars had dust disks more than 1,000 astronomical units (AU) apart, but here astrophysicists focused on cases with stars smaller than 500 AU, which almost never happens was.
40% of these systems have a dust disk, which means that planetesimals must have formed and therefore most likely telluric planets, stelluric planets and not gas giants, gas giants, orbit these stars. This number is slightly higher than that observed for individual stars. However, if we consider that binary stars make up almost two-thirds of the stars in the galaxy, the conclusion follows itself: Planets where we can observe double sunsets like Tatooine must be more common than terrestrial planets with a single sunset!
To get a reasonably accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then click on “Subtitles” and finally “Auto-translate”. Select “French”. © NASA/JPL
What amazed researchers most was that close binary systems, where the two stars are particularly close to each other, accounted for more than 60% of the cases recorded. While stars 3 to 50 AU apart have, on the contrary, a deficit of detectable dust disks. Surprisingly, the formation of close binary star systems would therefore favor the formation of a planetary system. Finally, from 50 to 500 AU we discover disks again, but around a single star of the pair, as shown in the diagram below.
Which led David Trilling to say: “Binary systems have historically been largely ignored because they are the most difficult to study. but they could well be the most common places where planets form in our galaxy “. Information that will certainly benefit the participants of the SETISETI program and delight fans of the Yoko Tsuno series.