Astronomers have noticed a strange, first-of-its-kind exoplanet, meaning a planet orbiting the solar system outside ours. Exoplanet HR 5183 b, a gas giant three times the mass of Jupiter, orbits its parent star on a distant, ovoid path that hesitates to be near and then away from the sun. For comparison, if HR 5183 b were in our solar system, its orbit would carry it from the asteroid belt to the orbit of Neptune, the farthest planet in our Sun.
The planet is especially unique given what we know about solar systems, conventional wisdom and observations suggest that circular orbits, such as those occupied by planets in our solar system (including Earth), are the most stable in the long run and in this is most commonly observed in mature solar systems. If planets violently orbit in a manner similar to HR 51
The planets of the Sun – and the protoplanets that preceded them – may have had much more chaotic, elliptical orbits in the days of the early solar system. In truth: more than 4 billion years ago, the Earth was struck by a Mars-sized body named Thea. Due to the current stable orbits of the bodies of the solar system, such massive collisions (thankfully) are no longer possible.
These findings will be published shortly in a study in the Astronomical Journal. Other giant planets with a slingshot-like orbit have been found around other stars in different solar systems, but none of those worlds have been located at the outer edges of their star systems like this.
"This planet is different from the planets in our solar system, but more than that, it is unlike any other exoplanet we have found so far," Sarah Blunt, lead author of a recently released study, said in a media statement. "Other planets discovered far from their stars tend to have very low eccentricities, which means their orbits are more circular."
Blunt added because this planet is so unique, it "speaks of some difference in the way it has either evolved or evolved over other planets. "
Co-author Michael Endle of the McDonald Observatory agreed.
" This new exoplanet is extremely and very interesting in many ways, "he said in a statement. a record orbital period of over 50 years, which is much longer than for other planets discovered by this technique. And it orbits its star in a very elongated, ovate orbit. ”
Researchers discovered exoplanets using the radial velocity method, a method of discovery that identifies new worlds by tracking their parent stars 'oscillating' in response to gravitational tugs from these planets. Andell said "something dramatic must have happened to change its orbit."
Since the 1990s, astronomers have been observing HR 5183, the planet's parent star. It is said that the planet orbits its star approximately every 45 to 100 years. HR 5183 b spends most of its time moving in the outer part of its star's planetary system, then accelerating and slinging around its star, in accordance with Kepler's laws for the motion of the planet.
"For almost 20 years, our data shows no sign of a planetary satellite," said Endle. "And then we watched a sling that lasted only about two years."
It's strange to imagine a huge sling on the planet. around her star, not unlike a comet. Asked what this solar system might look like, Avi Loeb, chairman of the Harvard astronomy department, told Salon via email: "To bring a planet launched into such an extended orbit by initially a circular orbit, it has to move the orbit to another giant, or a passing star. "
Regarding why this never happened in our own solar system, Loeb stated that the orbits of Jupiter and Saturn are not approaching enough to make Jupiter make Saturn
"The force of gravity during the meeting of the two planets must exceed the force that holds the ejected planet in a circular orbit around the Sun," Loeb said. "Since the Sun is a thousand times more massive than Jupiter, the disturbing planet must travel very close to the planet struck."
He added: "If a passing star gives a boost, the passage may be comparable to the separation of the struck planet. a planet from its host star. "
Endle says that we usually think that a planet is orbiting, but" a close encounter with another massive planet may have thrown it one long way around the star. "
Researchers said that this planet repeats how little we understand about planets outside our solar system. Before 1995, the year the first exoplanet was discovered, we didn't even know if there were planets in other solar systems. Nearly two decades later, 4,000 exoplanets have been discovered.
"In order to understand planetary systems throughout our galaxy, we need to find and study examples of the full range of possible systems," Philip McQueen, Technology Lead and Observer for M cDonald Observatory Planet Search, said in a statement. "While thousands of systems have been found by spacecraft, a system such as HR 5183 is unlikely to be found by past or present spacecraft."