Not all planetary systems are the same. There in the Big, Vast Galaxy, a number of different formations have been observed, some of which are very different from our home system. These include extrasolar planets, or exoplanets, that revolve not around one star, but two stars, like a fantasy star Wars Tatooine’s world.
Now, for the first time, astronomers have been able to detect the tiny gravitational force that an exoplanet exerts on a host star, giving us a new tool for exploring and exploring these exotic worlds.
The exoplanet itself is not a new discovery. Its name is Kepler-16b, and it is located 245 light-years away, and Its discovery was announced in 2011..
It has been hailed as the first confirmed and unambiguous discovery of an exoplanet orbiting two stars in what we call a circular orbit. As such, it has been looked at by astronomers a lot, and we know a lot about it.
This makes it ideal for trying something new – in astronomy, using a well-characterized and well-thought-out target is a good way to see if the techniques are working.
In this case, a team led by astronomer Amaury Triaud of the University of Birmingham in the UK wanted to see if they could detect the planetary system by wobbling one of its stars, a technique known as radial velocity.
“Kepler-16b was first discovered 10 years ago by NASA’s Kepler satellite using the transit method,” Explanation of the astronomer Alexander Santern from the University of Marseille in France.
“This system was the most unexpected discovery made by Kepler. We chose to operate our telescope and restore Kepler-16 to validate the radial velocity methods.”
When we search for exoplanets, there are a number of different ways, but two are the most common. By far the most productive method is what we call the transit method. The space telescope will peer into a patch of sky, looking for faint, regular dips in starlight that indicate an exoplanet passing between a star and us.
As mentioned earlier, the second fruitful method is the radial velocity method, and this depends on the gravitational complexity of a planetary system. Stars, as you can see, are not stationary, stationary bodies, around which exoplanets revolve. Each planet exerts its own gravitational pull on the star, causing the star to vibrate slightly, like a disk ejector. The sun does this too, mainly influenced by Jupiter.
This movement changes the observed light from the star. As the star moves away, the wavelengths stretch and increase slightly toward the red end of the spectrum; As it approaches, the wavelengths are compressed and shifted towards the blue end of the spectrum. Astronomers can use these changes to discover the presence of an exoplanet orbiting the solar system.
Previously, this was only done on individual stars. Binary stars are a more complex possibility; Since they orbit each other, they have much greater motions through space, which makes detecting the much smaller gravitational pull of any exoplanets orbiting the Solar System more difficult.
To circumvent the problems that arose from trying to separate the spectra of two bright stars, the team targeted a system with one brighter star and one fainter star. It worked. The 1.93-meter telescope at the Haute-Provence Observatory in France detected a radial velocity signal from the brighter star.
This can help us learn a lot. For one thing, radial velocity measurements show how much the star is moving, which can give astronomers accurate measurements of one of the main properties of an exoplanet — its mass.
The team’s measurements showed that Kepler-16b is about one-third the mass of Jupiter, consistent with previous estimates.
In turn, this information can help us learn how circular worlds formed, which is difficult to explain using current planetary formation models. Around a single star, a disk of dust and gas called a protoplanetary disk — remnants of the star’s own formation — is thought to clump together into planet-forming clumps.
“Using this standard interpretation, it is difficult to understand how circular planets exist. This is because the presence of two stars interferes with the protoplanetary disk, and this prevents dust from clumping into the planets, a process called accretion,” Clarified Triod.
“Perhaps the planet formed far from the two stars, where their influence is weaker, and then moved inland in a process called disk-driven migration—or, alternatively, we may find that we need to review our understanding of the process of planetary accretion.”
More detailed information about the types of exoplanets in circular (or even circumferential) orbits may help astronomers solve this problem. The team hopes that their work will pave the way for future discoveries, and indeed discoveries, of circular worlds.
The search was published in Monthly Notices of the Royal Astronomical Society.
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