by A new catalog of 126 worlds outside the solar system features a cornucopia of newly discovered planets – some of which are extreme and exotic in nature, but others could support life as we know it.
The catalog’s mix of planets is further evidence of the wide and wild variety of worlds outside our cosmic backyard; it even shows that our solar system is perhaps a little boring. But, despite the fact that these planets are so different from Earth and its neighbors, perhaps they can help us better understand why our planetary system looks the way it does, revealing our place in the wider cosmos.
The catalog of exoplanets, or “exoplanets,” was created using data from NASA’s Transiting Exoplanet Survey Satellite (TSES) in collaboration with the WM Keck Observatory in Hawaii.
“With this information, we can begin to answer questions about where our solar system fits into the vast tapestry of other planetary systems,” said Stephen Kane, Principal Investigator of the TESS-Keck Survey and an astrophysicist at the University of California, Berkeley. Riverside, in a. statement.
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The new TESS-Keck Survey of 126 exoplanets stands out from previous exoplanet surveys because it contains complex data about most of the planets included.
“Very few of the previously known exoplanets have mass and radius,” Kane said. “The combination of these measurements tells us what the planets might be made of and how they formed.”
“See red” to measure exoplanet masses
The catalog was built over three years as the team used 13,000 measurements of tiny “wobbles” that planets make as they orbit their stars and exert a slight gravitational tug on them. This tug is caused by a star moving slightly away, then slightly towards Earth.
When stars are pulled away slightly, this stretches the wavelengths of light they emit, moving them towards the “red end” of the electromagnetic spectrum. When stars move toward Earth, the wavelength of the light they emit is slightly compressed, making it “blurrier.”
The exploitation of redshift and blueshift in this way is called the “radial velocity method” by astronomers. Because the strength of gravity exerted by a planet on a star is proportional to its mass, it is a good way to determine mass. Thus, the radial velocity method allowed Kane and the team to determine the masses of 120 confirmed exoplanets and six exoplanet candidates.
“These radial velocity measurements allow astronomers to detect and learn the properties of these exoplanetary systems,” said Ian Crossfield, a University of Kansas astrophysicist and catalog co-author. “When we see a star drifting regularly back and forth, we can infer the presence of an orbiting planet and measure the planet’s mass.”
Interestingly, some of the 126 exoplanets in the TESS-Keck Survey could deepen astronomers’ understanding of how a variety of planets form and evolve.
Weird Super Earths, sub-Saturns and more!
Two of the new planets seen in the TESS-Keck Survey orbit a sun-like star called TOI-1386, located about 479 light-years away.
One of these exoplanets has a mass and width somewhere between the solar system gas giant Saturn and the smaller and less massive ice giant Neptune. That planet, named TOI-1386 b, is a “sub-Saturn” planet and a great target for planetary scientists.
“There is an ongoing debate about whether sub-Saturn planets are really rare, or whether we are just bad at finding planets like this,” discoverer and UCR graduate student Michelle Hill said in the statement. “Therefore, this planet, TOI-1386 b, is an important addition to this demographic of planets.”
At a distance from its parent star, which is about 17% of the distance between Earth and the sun, TOI-1386 b takes only 26 Earth days to complete an orbit.
His newfound neighbor is a little more relaxed. TOI-1386 c is a puffy gas giant about as wide as Jupiter, but only 30% the mass of the largest planet in the solar system. It sits about 70% of the distance between Earth and the sun from its parent star, and has a year that lasts about 228 days on Earth.
Another remarkable world among this batch of exoplanets is about half the size of Neptune, with more than ten times the mass of Earth, it orbits TOI-1437 (also known as HD 154840), and is located about 337,000 light years away .
Named TOI-1437 b, the sub-Neptunian planet orbits its star at about 14% of the distance between Earth and the sun, and lasts a year of about 19 Earth days. Discovered by TESS through the tiny dip in light it produces as it crosses the face of its star, TOI-1437 b is one of the few sub-Neptunes known to host its star with a good mass and radius. defined by him.
TOI-1437 b also highlights a strange absence in our cosmic backyard.
“Planets smaller than Neptune but larger than Earth are the most common worlds in our galaxy, but they are absent from our own solar system,” discoverer and UCR graduate student Daria Pidhorodetska said in the statement. “Every time a new one is discovered, we are reminded of how diverse our universe is and that our lives in the cosmos may be more unique than we realize.”
Another interesting exoplanet detailed for the first time in this new catalog is TOI-1798 c, a super-Earth that orbits an orange dwarf star so close that its year lasts only about 12 Earth hours.
“One year on this planet is less than half a day on Earth,” study lead author Alex Polanski, a University of Kansas physics and astronomy graduate student, said in the statement. “Because of their proximity to their host stars, planets like this one are also very hot – receiving more than 3,000 times the radiation that Earth receives from the sun.”
This makes the TOI-1798 planetary system, which also hosts a sub-Neptune planet that completes an orbit in about eight days, one of the few star systems known to have an inner super-Earth planet with an ultra-short period (USP ) orbit.
“While most of the planets we currently know orbit their star faster than Mercury orbits the sun, USPs take this to extremes,” Pidhorodetska added. “TOI-1798 ca orbits a star so fast that one year on this planet lasts less than half an Earth day. Due to its proximity to its host star, USPs are also extremely hot – receiving more than 3,000 hour of radiation that the Earth receives from the sun.
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The release of the TESS-Keck Survey Mass Catalog means astronomers now have a way to delve deeply into the work of TESS, which launched in April 2018, and measure how it has changed our understanding of exoplanets.
With thousands of planets from the TESS mission alone yet to be confirmed, the release of exoplanet catalogs like this one is set to become more common.
“Are we unusual? The jury is still out on that one, but our new mass catalog represents a big step toward answering that question,” Kane said.
The exoplanets are described in the Thursday (May 23) issue of The Astrophysical Journal Supplement.
