After several years of study Proxima Centauri Astronomers have finally found evidence that this star has a planet, and very similar to the Earth: the size of a little more. In addition, the orbit of the planet is in the habitable zone of the star, ie, on the surface of the water can exist in liquid form.
Modern audiences are no longer surprised by reports of exoplanet discovery. The emergence of effective detection methods and devices such as the Space Telescope, “Kepler”, the expense recorded ezkoplanetam in the thousands. Interest is the discovery of extrasolar planets and Earth-like exoplanets in star systems located close to the solar system. The current news, reported by the European Southern Observatory meets once both conditions. New Earth-like planets so close to Earth that’s nowhere close.
Found planet called Proxima b. It revolves around Proxima Centauri – a red dwarf star, one of the three components of Alpha Centauri. The distance from Earth to Proxima Centauri is 4.25 light years, there are no stars, which would be located even closer. The previous record for planets on which life may appear, was equal to 11.7 light years. He belonged to the Wolf 1061c planet in the constellation Ophiuchus.
On the opening of the journalists of the German weekly “Der Spiegel” reported for the first time in early August, citing an anonymous source. Astronomers have taken the time to confirm this news. However, earlier this week, the European Southern Observatory announced, and on 24 August held a press conference at which scientists have described in detail the Proxima b. Also, the results of their work are reflected in an article published in the journal Nature.
Observing Proxima Centauri scientists conducted using the High Accuracy Radial velocity Planet Searcher (HARPS) installed in the La Silla Observatory in Chile 3,6 meter telescope of the instrument. In 2012, with it discovered a planet that orbits around another component of the triple star – Alpha Centauri B, however, is now the existence of this planet called into doubt
In order to detect extrasolar planets HARPS uses spectrometric measurements of the radial velocities of the stars ( “. Doppler “) method. It allows you to record the motion of the star signs. Because, if the star has a planet, or several planets, they revolve around a common center of mass, the motion of the star allow us to calculate the invisible planet. Normally, to this effect was evident, it requires the presence of several planets or stars one, but a very large planets (such as the so-called “super-Jupiter”). If we are talking about Earth-like planets, their impact on the position of the stars would be negligible. The total mass of the star center of the system – the planet, in this case, is likely to be inside the star, so it will make only small fluctuations. But the proximity of Proxima Centauri to Earth to track and allowed them.
Scientists have observed signs of planet Proxima b for 60 nights in a row since January 2016. According to their calculations, the mass of the planet just 1.3 times the Earth’s mass, and around its star, it refers to the period of 11.2 days. Proxima b is located very close to the star, at a distance, is only 5% of the distance from Earth to the sun. But there is a chance that the surface of this planet did not look like a red-hot desert. The fact that Proxima Centauri – not too bright star. According to the calculations Proxima b receives only 65% of the energy that the Earth receives from the sun. So on the surface it can actually be liquid water. “There is a reasonable suspicion that this planet may be able to become a repository of life”, – said one of the authors of the discovery Guillem Anglada-Escudé (Guillem Anglada-Escudé) from Queen Mary University in London
But still. Proxima is unlikely to b particularly favorable conditions for life. The gravitational force is likely oriented it so that one hemisphere is always looking to Proxima Centauri, and the second – in the opposite direction, just as the moon is deployed in relation to the Earth. As a result, on one half of the planet’s permanent day and the next night, and the temperature difference between them is huge. While approximate calculations show that the average temperature on Proxima b must be equal to -40 ° C, if it is available on the atmosphere, then this figure will be higher. For comparison, the Earth, devoid of atmosphere and ocean average surface temperature would be equal to from -20 ° C to -30 ° C.
Due to its proximity to Proxima Centauri, the planet gets 100 times more high-energy radiation ( in ultraviolet and X-rays) than the Earth. This factor, too, is not conducive to the presence of life. Compounding situation and the fact that Prksima Centauri – flashing variable star, and during flares its luminosity can be increased several times. Protection against high-energy particles can serve as the magnetic field, but we do not know whether it is a planet Proxima b.
In addition to discussions about the possibility of having to Proxima b water and of life that seem to be still somewhat premature, the new planet and other mysteries are related. For example, the formation of rocky planets itself in such a short distance from the star it seems unlikely. By assumption, as expressed Gillemom Anglada-Escudé, Proxima b could be formed in another place, far away from the star, and then for unknown reasons, is to move to a closer orbit. If so, then the presence of water on the planet becomes more likely.
Now, astronomers began to try to fix the passages Proxima b against the starry disk of Proxima Centauri. Observation of such passages will allow them to more accurately determine the size and mass of the planet, and thus calculate its density, to test the hypothesis that it is rocky rather than gaseous planet. Star light passing through the atmosphere b Proxima, will enable scientists to find out what gases are included in its composition. But the chances to observe such passages in a small Proxima Centauri. Therefore, the main hopes for space telescopes, “James Webb” and TESS (Transiting Exoplanet Survey Satellite), which are only planning to run.
No comments:
Post a Comment