NASA Goddard / Robert Simmon (Earth), NASA / JPL
Astronomers have discovered an exoplanet twice as large as the Earth, which can be an ideal candidate for observations using the James Webb space telescope, which is scheduled to be launched in 2021. Now scientists know quite a few smaller planets, but the new exoplanet has two advantages: it is relatively close to the Earth and its mother star is bright enough to allow Webb to measure the spectral characteristics of the planetary atmosphere, according to an article published on the ArXiv.org website. and accepted for publication in The Astronomical Journal.
Today, astronomers often discover planets that are many times larger than ours, such as hot Jupiters or super-neptuns. However, celestial bodies that would be 1.5-2 times larger than the Earth are relatively rare, which is largely due to the technical limitations of modern telescopes that can not always catch a weak signal from the transit of a medium-sized planet.
Canadian researcher Merrin Peterson (Merrin Peterson) together with colleagues analyzed the last set of data received by the Kepler telescope during the mission K2. The researchers found periodic dips in the light curve of the star Wolf 503, which is in the constellation of the Virgin and is 145 light years away from us. This is an orange dwarf of the spectral class K3.5V, by mass slightly inferior to the Sun. Around it, as analysis has shown, the planet, called Wolf 503b, rotates – it caused regular changes in the brightness of the star. Its radius is only twice as large as that of the Earth, but it is almost 10 times closer to the light than Mercury to the Sun.
To ensure the reliability of the discovery, scientists received images of the system at the Palomar Observatory, and also checked the archival data. This allowed us to reject the hypothesis of a possible companion star. In the future, astronomers intend to measure the radial velocity of Wolf 503 to determine the mass of the planet: the larger it is, the stronger its gravitational effect on the light. Knowing the mass of Wolf 503b and its radius, researchers will be able to estimate its density, which, in turn, will tell about the possible structure of the celestial body. For example, to be similar to the Earth, it should have 14 times the mass. If this is a mini-neptune, then this value will be much smaller.
In the future, the Wolf 503 will be an ideal candidate for research using the James Webb telescope, which is scheduled for launch in 2021. Today, there are quite a few planets of similar size that would revolve around such bright stars – they are more often found in more dim red dwarfs. During transit, the passage between the star and the observer, “James Webb” due to the brightness of the star will be able to get the spectrum of its atmosphere, which will allow scientists to determine its composition.
Recently, the communication systems of the James Webb space telescope have successfully passed the test tests. Nevertheless, the device still continues to pass various tests. It is expected that after the beginning of the work it will help scientists to obtain density estimates for a number of planets, as well as answer fundamental questions regarding their atmospheres.