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Three planets with potential for life orbit a cold red dwarf close to the solar system

Lead researcher: "Systems orbiting tiny stars are the only places where we can detect life on an Earth-sized planet with our current technology. Therefore, if we want to find life elsewhere in the universe, this is where we should start looking."

An artist's rendering of a view from the surface of one of the three planets orbiting the cold dwarf star TRAPPIST-1 40 light-years away. CREDIT: ESO/M. KORNMESSER
An artist's rendering of a view from the surface of one of the three planets orbiting the cold dwarf star TRAPPIST-1 40 light-years away. CREDIT: ESO/M. KORNMESSER

A team of astronomers led by Michel Gillon, from the Institute of Astrophysics and Geophysics at the University of Liège in Belgium, used the TRAPPIST telescope (the TRAnsiting Planets and PlanetesImals Small Telescope) – a robotic telescope located at the Southern European Observatory in La Silla, Chile and operated by the University of Liège, to observe the star 2MASS J23062928-0502285, now known as TRAPPIST 1. They discovered that this dim and cool star is slightly faded at regular intervals, indicating that several objects are making their way between the star and Earth. A detailed analysis showed that these are three planets with sizes similar to those of the Earth.

TRAPPIST 1 is an extremely cold dwarf, much lighter and redder than the Sun and barely larger than Jupiter. Such stars are very common in the Milky Way and are long-lived, but this is the first time that planets have been found around one of them.

Despite being so close to Earth, this star is too dim and difficult to see with the naked eye or even with large telescopes. It lies in the direction of the Aquarius constellation.

Emanuel Jahin, one of the authors of the new study, is excited: "This is really a paradigm shift in regards to the population of Earth-like planets and in regards to the ways to find life in the universe so far. The existence of planets orbiting such 'red worlds' was only theoretical. But now we have not just one single star orbiting a faint red star but a whole system of three planets! "

Michal Gillon, the lead author explains the significance of the new findings: "The reason why we are trying to identify Earth-like planets around the coldest small stars in the neighborhood of the solar system is simple: systems surrounding tiny stars are the only places where we can detect life on a planet the size of Earth with our current technology. Thus, if we want to find life elsewhere in the universe, this is where we should start looking. "

Astronomers will look for signs of life by studying the spectrum of light coming from these planets to Earth. Planets of this size are usually flooded with starlight. Only in the case of ultracold and faint red dwarfs like this is the effect of life large enough to be detected.

Follow-up observations made with large telescopes, including HAWK-I at ESO's Very Large Telescope – ESO's eight-meter diameter telescope in Chile, showed the team that the planets orbiting TRAPPIST 1 are very similar in size to Earth. The two planets have a cycle time of 1.5 and 2.4 days respectively, while the cycle time of the third has not been determined and is still estimated in a fairly large range - 4.5 to 73 days.

Because of their short orbital period, their distance to their sun is 20 to 100 times closer than Earth is to the sun. The structure of this planetary system is much more similar to the lunar system of Jupiter than to our entire solar system," Gilon explained.

Although they orbit very close to their red dwarf host, the two inner planets receive only 4 and 2 times respectively the amount of radiation that Earth does, because their star is much fainter than the Sun. This puts them closer to the star relative to the habitable zone of this system, although life on them is still possible. Regarding the third planet whose orbit is still unknown, it probably receives less radiation than the Earth but in some scenarios at least it is still enough for it to be within the habitable zone.

"Thanks to huge telescopes currently under construction, including ESO's E-ELT and the James Webb Space Telescope shared by NASA, Europe and Canada, the first of which will be operational and the second of which will be launched in 2018, we will soon be able to study the composition of the atmospheres of these planets to search for them Traces of water or traces of biological activity. This will be a huge step in the search for life in the universe" concludes Julian de Wit, one of the authors of the article from MIT.

This research opens up a new direction for planet hunting, because about 15% of the stars near the solar system are extremely cold red dwarfs, and not just any planets, but even ones that could be habitable cousins ​​of Earth.

 

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13 תגובות

  1. It doesn't seem to me that 40 light years is "close enough" for this method... The radius of the earth in its orbit around the sun is 8 minutes light years, that is, the diameter of the rotation is 16 light minutes which is really, really negligible compared to 40 light years... It turns out a triangle with a square base And really, really, really long ribs... base angles of almost 90 degrees, not good enough.

    But maybe with the help of the second method listed there.

  2. Elementary question
    How do you measure the distances to the stars in the galaxy?
    After all, Hubble's law (expansion of the universe) does not work inside the galaxy?

  3. Yes, it's not far in astronomical terms, but the main point of the article was that this type of star allows for a more in-depth study of the planets around it, because you can get a stronger reading of their atmospheres by analyzing the light from the star passing through them.
    As long as we don't have the technology to travel at speeds close to light, or warp space-time, we'll probably have to make do.
    From this it can be concluded that we may have information on a number of worlds whose data suggests the invention of life on them, before we can actually visit them, if at all. A large number of them are around dim stars such as this one.
    But, it brings us one level closer to being an interstellar culture.

  4. There is an excellent and up-to-date lecture of about 80 minutes on YouTube on the subject of finding life on other planets:
    Innumerable Globes Like This One: The Search for Life Beyond the Solar System – YouTube
    https://www.youtube.com/watch?v=CdSyGpikn5I
    I will refer to 2 key points according to the lecture:
    So far, close to 2,000 constellations have been discovered around glasses or stars.
    According to a statistical analysis of these data, the first star found in the "living zone" will be 10 light years away from Earth.
    Statistically at a distance of 30 light years from Earth in any direction,
    25-30 planets are expected in the "living zone" around the bright star.

    To determine whether a planet is in the "life zone", i.e. temperatures suitable for liquid water, there are 4 data:
    The amount of sunlight reaching the star, the percentage of energy returned, the amount of sunlight "absorbed" and heating by greenhouse gases.
    In comparison, Venus receives almost double the amount of light compared to Earth because of its proximity to the Sun.
    The amount of energy returned from Manga is a little more than twice as much as the Earth, so the amount of energy absorbed is almost the same.
    But the difference of the greenhouse effect is significant: 33 degrees Celsius on Earth and 510 degrees in Venus.
    That's why the average temperature on Earth is 16 degrees and 470 degrees Celsius!
    In most of the technologies available today, only the first figure can be calculated, i.e. the amount of sunlight reaching the star.
    Therefore, it is still not possible to determine what the approximate temperature of the planet is.
    I don't think the speaker was referring to the cutting edge technology in question or viewing planets whose suns are so dim.

  5. really close
    If it will take 20 years to reach a distance of 4 light years then it can be extended just to explore it will take some 200 years if they start the journey today plus another 40 years to get the picture.

  6. A',

    Check Boint (digital section) there is also a parallel article on the subject, if I remember correctly 50 light years which is quite close.

  7. If they looked at our solar system from afar without knowing it, how many of our neighboring planets would they say have the potential to find life?

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