We already knew about the ability of the James Webb Space Telescope to record unprecedented images of both the deep sky and our planets. neighbours in the solar system. But it’s not only capable of taking these pictures: it’s also been designed to analyze the infrared radiation of objects. cold very far. For example, extrasolar planets or exoplanets.
After studying the emission spectrum of the exoplanet VHS 1256b (located 40 light years from Earth and 19 times more massive than Jupiter), an international team of researchers came to the following conclusion: this giant extrasolar planet contains grains of sand in its atmosphere, as well as water, methane and carbon monoxide .
This is the first time that such a large number of molecules have been identified on a planet outside the solar system at the same time.
Before commenting on the new results, let’s delve into the world of extrasolar planets.
Outside the solar system
From school, we study the planets of the solar system (even singing their names, ordering them in proximity to the Sun).
Of this select group of eight (Pluto has come to be considered a dwarf planet, although controversy still exists), four are rocky planets (Mercury, Venus, Earth, and Mars), and the other four, the furthest from the Sun, are gas giants. (Jupiter, Saturn, Uranus and Neptune). In ancient times they were called wandering starsbecause his position in the firmament was not constant, as in the case of fixed stars.
Although astronomers have assumed the existence of planets outside the solar system, it was not until October 6, 1995 that the first exoplanet was discovered orbiting a main sequence star. It was the exoplanet 51 Pegasi b, larger than Jupiter and orbiting the star Helvetius about 50 light years away.
The finds never stopped growing. For example, super earth Gliese 876 d (one of the first terrestrial exoplanets) and the TRAPPIST-1 planetary system.
The top image is curious: seven rocky exoplanets (similar in size to Earth) orbit the red dwarf. As an indicative fact, the distance of these planets from their star is much less than the distance of the planet Mercury from the Sun.
A year on the most distant planet (TRAPPIST-1h) it lasts 18.8 Earth days, while the nearest one (TRAPPIST-1b) makes a revolution in just 1.5 days.
It is the recent TRAPPIST-1b study (based on infrared data collected by James Webb) that shows that the exoplanet no meaningful atmosphere with temperatures up to 230 degrees Celsius on the day side.
By 2022, NASA has confirmed about 5,000 exoplanets out of the hundreds of billions that our galaxy can host. The recent discovery of the exoplanet TOI 700 e (similar in size to Earth and within the so-called habitable zone) has become important, since liquid water can be on its surface. planets ideal for the development of life as we know it.
But how did astronomers manage to detect these exoplanets?
Methods for detecting exoplanets
It is likely that we are referring to the image of a planet in the solar system, taken by powerful ground or space telescopes (capable of capturing the light reflected by such objects). cold). For example, this image of Jupiter taken by the Hubble Space Telescope (and recorded in the visible, infrared, and ultraviolet) shows unprecedented detail in this gas giant.
Problem with this detection method straight lies in the difficulty of capturing very dim light reflected by a distant exoplanet (where in most cases they would be blinded by the parent star).
However, astronomers have been able to photograph an extrasolar planet (2M1207b) orbiting its star (2M1207).
On the other hand, indirect detection methods are widely used in astronomy. Two stand out:
-
Radial velocities: based on variations in the speed of the central star due to the gravitational effect of a planet (virtually invisible) orbiting it. This technique has proven to be very useful for detecting larger exoplanets near their central star.
-
Transits: Consists of observing the decrease in the intensity of light from a star as an exoplanet orbits in front of it. He was also very successful in discovering large extrasolar planets.
Turbulent exoplanet VHS 1256b
Returning to our exoplanet VHS 1256b, this gas giant orbits its two stars at four times the distance that Pluto makes around the Sun, completing one revolution in about 10,000 years.
Therefore, the light emitted from its atmosphere will not mix with the light from its parent stars. This allows very reliable results of its composition and dynamics to be obtained.
On the other hand, Webb did not analyze this planet using the indirect methods described above. Instead, he recorded the emission spectrum of his turbulent atmosphere (reaching a temperature of 815 ⁰C) using two onboard instruments.
Thus, the graph in the top figure shows the radiation emitted by the VHS 1256b as a function of the infrared wavelengths used by the NIRSpec (horizontal axis, 1 to 5 microns) and MIRI (5 to 5 microns) instruments. ).
It is known that for certain wavelength ranges, the curve represents emission maxima (associated with various chemical compounds present in the atmosphere of an exoplanet). In particular, James Webb was able to identify water, methane, carbon monoxide and silicates in the atmosphere of VHS 1256b.
The presence of these larger silicate grains is what the scientists behind this discovery classify as very hot sand particles. On the other hand, smaller grains can resemble tiny particles of smoke.
This is the largest number of molecules identified simultaneously on an extrasolar planet (due to the wide range of infrared wavelengths that the NIRSpec and MIRI instruments can measure).
Will James Webb be able to detect other molecules, such as oxygen or carbon dioxide, in the atmosphere of very distant planets? It’s almost certainly a matter of time.
Oscar del Barco Novillo, assistant professor. Department of Applied Physics, University of Zaragoza
This article was originally published on The Conversation. Read the original.
Source: RPP
I am Ben Stock, a passionate and experienced digital journalist working in the news industry. At the Buna Times, I write articles covering technology developments and related topics. I strive to provide reliable information that my readers can trust. My research skills are top-notch, as well as my ability to craft engaging stories on timely topics with clarity and accuracy.