Beer Brotherhood in the constellation Aquarius

radjab By radjab, 24th Feb 2017 | Follow this author | RSS Feed | Short URL http://nut.bz/cmb7ql0d/
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So, what happened? Speaking briefly, then the red dwarf 2MASS J23062928-0502285 (his second name TRAPPIST-1) found 4 new exoplanets, size, density and estimated surface temperature of Earth-like and Mars. And now explain each word of this sentence.

To tell about the discovery of new exoplanets in TRAPPIST-1 system

A day after an extraordinary press conference, NASA's, at which representatives of the US space agency announced the discovery of new Earth-like planets (a word, by the way, not mentioning the great contribution made by the European telescopes), we decided to write in detail about this event, as far as possible without using the word " sensation "or" the first time in the history of mankind. " Still, this discovery not so grand as the registration of gravitational waves in the last year, though still a big step forward - especially in understanding the processes of formation of planets around stars of various types, the study of the chemical composition of planetary systems, comparing the characteristics of our solar system and all the new and newly discovered systems around other stars.

Where did the stars double name?

Why do the stars and the two names as all the same right: 2MASS J23062928-0502285 or TRAPPIST-1? The fact that the modern rules of the name assigned to the object by name or telescope observing program, which it opened. The star of the constellation of Aquarius was discovered during a survey of the entire sky in infrared light in the program 2MASS at the end of the 1990s. It was identified as unremarkable red dwarf of spectral type M8 - like objects in 2MASS catalog is now more than 500 million - and no longer be disturbed for several years. So far in 2015, long-term observations at the telescope TRAPPIST not led to the discovery of three planets orbiting this star. Then, to select it from a million such, she was given the additional name - TRAPPIST-1,

What a strange name for a telescope? This, of course, high technology acronym which stands for transiting Planets and planetesimals the Small Telescope , ie "Small telescope to search for transiting planets and planetesimals", but the Belgians who installed him in the observatory of La Silla in Chile, do not hide the fact that it is also homage to the famous monastery ale , which has long been brewed in their country. Telescope This, incidentally, is quite small, the diameter of its main mirror is only 60 centimeters - as much as, for example, and on the observation station Lighthouses near Odessa. It was built under the scheme Ritchey-Chretien (as telescopes "Hubble" or "Spitzer") - it allows him to take pictures without distortion of large parts of the sky (eg, the entire surface of the moon at a time). In addition, the presence of only two reflective surfaces hardly attenuates the light and allows you to monitor even very faint objects (in popular among amateur astronomers Schmidt telescopes and Maksutov established at least four reflecting or refracting surface). This is important because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. In addition, the presence of only two reflective surfaces hardly attenuates the light and allows you to monitor even very faint objects (in popular among amateur astronomers Schmidt telescopes and Maksutov established at least four reflecting or refracting surface). This is important because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. In addition, the presence of only two reflective surfaces hardly attenuates the light and allows you to monitor even very faint objects (in popular among amateur astronomers Schmidt telescopes and Maksutov established at least four reflecting or refracting surface). This is important because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. the presence of only two reflective surfaces hardly attenuates the light and allows you to monitor even very faint objects (in popular among amateur astronomers Schmidt telescopes and Maksutov established at least four reflecting or refracting surface). This is important because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. the presence of only two reflective surfaces hardly attenuates the light and allows you to monitor even very faint objects (in popular among amateur astronomers Schmidt telescopes and Maksutov established at least four reflecting or refracting surface). This is important because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it. because the main purpose of TRAPPIST telescope - search for comets, extrasolar planets, observation of small bodies of the solar system (for example, a telescope studied the dwarf planet Eris and Makemake ). Telescope the robot is controlled directly from the University of Liege in Belgium, and if you read the news day in Russia, then certainly at this time in Chile, he continues to search for new exoplanets, and you can even live to see how he does it.

What is the transit method?

As the first three bodies were discovered in the star TRAPPIST-1? Transit method , which is used by most hunters exoplanets, such as a telescope, "Kepler". The method consists of tracking the apparent brightness of the star (as it is not known in advance, in which the star has a planet, it is best suited here telescopes with a wide viewing angle, it is like TRAPPIST). If the star has a planet, and the plane of its orbit parallel to the line of sight of the telescope (that is, we see the "edge" orbit), then sooner or later, as the circulation in its orbit, the planet will close a part of the star, and for us it will be a little dimmer. It is still the most productive method: 24 February 2017 with the help of 3453 opened in 2707 exoplanets. But it has its drawbacks. In addition to the aforementioned restrictions on the inclination of the orbit, it is impossible to determine a number of important parameters such as the elongation of the orbit. In addition, if the exoplanet is far away from the star (and thus orbits slowly), the telescope must monitor this portion of the sky for a long time to notice it. If aliens suddenly try to find all nine planets of the solar system, they will have to watch out for us no less than 160 years, and still it will give them only one signal from Neptune.

Simple in words, the method requires very careful observations, as well as algorithms for filtering changes apparent brightness of the star that is not associated with exoplanets (for example, caused by turbulence in Earth's atmosphere).

However, in the case of system TRAPPIST-1, it does not become a hindrance - surveys conducted since 2013, have allowed to register multiple periodic changes in brightness of the star, which could not be caused by any other reasons other than the passage of exoplanets by its disc. According to the research in 2016 it was published the release of the European Space Agency, and we detail covered . It seemed that was all new and unexpected, this star is no longer fraught - until four days ago there appeared a message on emergency NASA press conference.

How to detect new exoplanets?

How can I detect just four new exoplanets have seemingly already well-studied star? The fact that after the discovery of the first three planets, the team of astronomers led by Michael Gillonnay received observing time on the Very Large Telescope in Chile (yes, it is called: Very Large Telescope), and after the article was published in 2016 found that a signal that they were originally taken for the passage of the planet TRAPPIST-1d (each new discovered planet gets the name of the host star and unoccupied following the letter of the Latin alphabet starting with «b»), is in fact a superposition of signals from three planets at once. It was so unexpected for the scientific community that the team identified several observational time on the world's largest telescopes, including 20 days (that's a lot!) of continuous use of the space telescope "Spitzer". The work of such giants as two-meter Liverpool Telescope on La Palma, the 3.8-meter telescope UKIRT in Hawaii, four-meter telescope William Herschel in the Canary Islands, together with a number of smaller telescopes gave few new signals from unknown objects passing across the stellar disk and partially eclipsing her. But just 20 days of the "Spitzer" gave 34 new signal in September 2016, which allowed accurately establish the existence of three new planets - all them were six. Moreover, the imposition of the original signal was not random - the orbits of these planets are in resonance.

These laws, as the authors note, indicate that the planet is likely to have formed in the same cloud of gas and dust in the used of lshem distance from the star and gradually lose angular momentum, migrated from near the orbit. Such theories have been put forward over ten years ago, they are now well developed, and surveillance TRAPPIST-1 system in line perfectly with the predictions. Something like this, for example, was supposed to happen with the satellites of Jupiter - and Michael Gillonnay stresses in the article that TRAPPIST-1 weight as many times greater than the mass of all the planets, as Jupiter in the mass of his companions. Indeed, it is believed that Europe, Io, Callisto and Ganymede also formed from a flat disc, consisting of dust and gas that surrounded the young Jupiter. Thus, the study of the gas giant,

We should also say that "Spitzer" saw another signal - once at 75 minutes TRAPPIST-1 became fainter at 0.35 per cent, and no longer see the world could not be the cause. According to astrophysicists, it indicates the presence of another, the seventh planet. At the time of the press conference, none of the participating telescopes could not register a signal of the second passage, so the orbit, and the planet parameters have to be judged according to these two numbers - the eclipse time gives the planet orbital velocity (and, according to the laws of Kepler , orbit radius ), and reduction of the visible star's brightness helps to set about the dimensions of the seventh planet.

What new exoplanets consist?

Now, knowing the number of planets, their orbits and the approximate radius, can you say something about the composition of planets - of which they are composed, is there water on them? To do this, you need to know the mass of each planet. Above we said that directly determine its transit method does not allow. However TRAPPIST-1, we were lucky the system: all of its planets are so close to each other (all their orbits are much closer to the star than Mercury's orbit to the Sun), they gravitationally interact with each other, then speeding up, then slowing its movement in orbits. This is manifested in the fact that each planet eclipses a star at different time intervals. During observations of the difference in the passage of the same planet on stellar disk reached 30 minutes. It orbits to that in the absence of disturbances remain unchanged for billions of years! Such variations in the transit time helped scientists to build analytical and numerical solutions and calculate the most probable mass of the planets. The reliability of these methods is highly dependent on the number of measurements, so the accumulation of new signal values ​​of the masses will be updated, but as long as they are in the range from one-half to one and a half Earth masses.

Knowing the mass and size of planets, you can calculate its density, and therefore, to speculate on what it is made. It is clear that there are great errors, but it appears that the five planets density differs from the Earth no more than 20 percent. This means that they must be rocky and are likely to contain water. The water connection is not as exotic as it may seem - it was detected on the surface of comets and asteroids, arrives to us from the backwoods of the solar system. Therefore, it may well turn out to be a part of the planets, which, as we know, were formed at a distance from the star TRAPPIST-1. It is proof of the existence of water on these planets we do not have, but I want to warn the reader against unreasonable skepticism: the hypothesis of scientists are taken not from the ceiling, and built on the results of the use of models with a variety of input parameters.

Comparison of densities detected exoplanets (colored dots) with the densities of the planets of the solar system (gray dots). Vertical postponed radius of planets across - their mass. It is evident that the planet TRAPPIST-1 system can have a structure similar to the Earth, Venus or Mars. However, it is worth paying attention to measurement error (horizontal colored lines) - they are very important and does not allow us to speak confidently about the composition of the planets.

if their climate is similar to the Earth?

And now it is possible and on the climate. The system is unique in the fact that six, or maybe seven planets fall in the habitable zone - the conditional range of distances from the star, where it warms the planet so that there could be unfrozen water. Most likely, all of the planet experienced a tidal capture by TRAPPIST-1, that is, make one revolution around its axis at the same time with a turn around the star. This means that, as the Earth and the Moon, they always turned to one side of it, in which the temperature is always higher than the other side dark. Theoretical calculations performed by different groups studying exoplanets suggest that this should not be an obstacle for the existence of liquid water - in the presence of a sufficiently dense atmosphere,

Professor of the Department of Theoretical Mechanics MIPT Vladislav V. Sidorenko explains how this can happen: "The fact that the planets orbit in TRAPPIST-1 have small radii contributes to gravitational capture - the establishment of a regime of motion when the planet is turned to a star of the same party. In this case, deformation of the planet tidal determined eccentricity of its orbit. Although the eccentricities of planets in TRAPPIST-1 low, coupled with the close position to the star having strong tidal deformation, which may lead to the release of a significant amount of heat in the bowels of the planet, which could be enough to sustain a significant geological activity. " It turns out that a small radius of the orbit not only creates the problem of heat transfer from one side gravitationally captured by the planet to the other.

Is there life on exoplanets?

If we talk about even more hypothetical probability of life on any of the planets of this system, it is necessary to tell about TRAPPIST-1 the star itself. This is a very dim red dwarf, the mass of which is barely enough to maintain thermonuclear reaction in the heart of its core. The temperature at the surface of the star in half the sun, it emits mostly in the infrared range (which is why infrared 2MASS review was opened and not one of the many optical earlier reviews). However, the proximity of the planets to the star partially compensates for the lack of its radiation on their surface falls enough heat to, as we have said, water (if there) remained liquid. The problems come from the other side - in the article by Peter Wheatley, published in 2016, immediately after the opening of the first of three planets, presents data on ultraviolet and X-rays stars TRAPPIST-1. And it is almost not inferior to the sun. With that exoplanets are much closer to the star, and, most likely, are not protected by a strong magnetic field, radiation and hard radiation on the surface of the earth must greatly exceed the performance.

In addition, these stars are much less stable than the sun, and frequent flare emissions and prominences is also unlikely to contribute to the smooth and healthy tan trappistariantsev potential (?). The same (and even pessimistic) estimates are given and the newly published article, Jack O'Malley-James of the University of Cornell - only a very specific composition of the atmosphere of the planet is able to protect its surface from the damaging action of X-rays. Particularly important to have a large amount of ozone. As a consolation, we can say that the class M8 Star live 500 times longer than the sun (up to a trillion years, far exceeding the age of the universe) and, as the star is still very young - she was only 500 million years old, trappisterian have in stock a lot of (?) time to adapt to the aggressive environment.

What's next?

However, all this is just speculation. Astrophysicists from other research groups have already filed an application for the use of the telescope "Hubble" in an attempt to "transmission" of the atmosphere of planets at their next passage through the disk stars, and "Kepler" have been seeing TRAPPIST-1 by collecting new data on transit. Well, of course, the launch of a space infrared telescope, "James Webb", scheduled for next year, too, is expected to look great - its a huge mirror, which is six times greater than that of "Hubble", should be sufficient to obtain new information about this amazing system. | nplus1.ru

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Aquarius, Beer Brotherhood, Constellation

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