Earth-sized planet discovered in our 'solar backyard'

“It's a useful planet because it might be like the early Earth.”

HD 63433d, a new Earth-sized planet discovered by astronomers, offers a rare glimpse into the early stages of the planet's evolution, given its close orbit around a young, Sun-like star.

A team of astronomers has discovered a planet closer and younger than any other Earth-sized world yet identified. It's a remarkably hot world, and its proximity to our planet and to a star like our Sun presents a unique opportunity to study how planets evolve.

The new planet was described in a new study recently published in the journal Astronomical magazine. Melinda Soares-Furtado, A NASA A Hubble Fellow at UW-Madison who will begin working as a professor of astronomy at the university in the fall, and recent UW-Madison graduate Benjamin Capistrant, now a graduate student at UW-Madison. University of Floridaco-led the study with co-authors from around the world.

The young, hot, Earth-sized planet HD 63433d lies close to its star in the constellation Ursa Major, while two nearby Neptune-sized planets — identified in 2020 — orbit farther away. Credit: Alyssa Jankowski

“It's an interesting planet because it could be like early Earth,” Soares-Furtado says.

Here's what scientists know about the planet:

• The planet is known as HD 63433d, and it is the third planet in orbit around a star called HD 63433.
• HD 63433d is very close to its star, completing its journey every 4.2 days.
• “Even though its orbit is really close, we can use follow-up data to look for evidence of outgassing and atmospheric loss, which could pose important constraints on how terrestrial worlds evolve,” Soares-Furtado says. “But that's where the similarities end — and end Significantly“.
• Based on its orbit, astronomers are relatively certain that HD 63433d is tidally locked, meaning one side of it is permanently facing its star.
• This side can reach a brutal 2300 degrees F It may flow with lava, while the other side is eternally dark.

What you should know about the planet star:

• HD 63433 is roughly the same size and type of star as our Sun, but (about 400 million years old) it is not even one-tenth the age of our Sun.
• The star is about 73 light-years from our sun, and is part of the group of stars moving together that form the constellation Ursa Major, which includes the Big Dipper.
• “On a dark night in Madison, you could see,” Soares-Furtado says [HD 63433] Through a good pair of binoculars.

The young, hot, Earth-sized planet HD 63433d lies close to its star in the constellation Ursa Major, while two nearby Neptune-sized planets — identified in 2020 — orbit farther away. Credit: Alyssa Jankowski

How scientists found the planet:

• The study's authors are collaborating on a planet-hunting project called THYME. In 2020, they used data from NASA's Transiting Exoplanet Survey satellite to identify two minor planets.Neptune– The size of the planets orbiting HD 63433.
• since then, he-goat It took four more looks at the star, collecting enough data for researchers to detect HD 63433d transiting between the star and the satellite.

What comes next:

• Researchers, including Andrew C. Nine, co-authors of the UW-Madison study, undergraduate student Alyssa Jankowski, and Juliet Becker, a professor of astronomy at UW-Madison, said there is a lot to learn from HD 63433d.
• The planet is in a unique position for further study. Its vibrant young star can be seen from both the northern and southern hemispheres, increasing the number of instruments, such as the Large Telescope in South Africa or the WIYN Observatory in Arizona (both of which the University of Wisconsin-Madison helped design and build) that can be trained on the system. .
• The star is much closer than Soares-Furtado studied, which may provide opportunities to develop new ways to study gases escaping from the planet's interior or measure its magnetic field.

“This is our backyard solar, and that's kind of exciting,” Soares-Furtado says. “What kind of information can a star this close, with such a crowded system around it, provide? How will that help us as we move on to search for planets among 100 other similar stars in this young group to which it belongs?”

Reference: “TESS Hunt for the Search for Young and Mature Exoplanets (THYME).” eleventh. “An Earth-sized planet orbiting a nearby solar-like host in the 400-million-year-old moving Ursa Major cluster” by Benjamin K. Capistrant, Melinda Soares-Furtado, Andrew Vanderberg, Alyssa Jankowski, Andrew W. Mann, Gabrielle Ross, Gregor Srduk, Natalie R. Hinkle, Juliette Becker, Christian Magliano, Mary Ann Limbach, Alexander P. Stephen, Andrew C. Nine, Benjamin M. Tofflemeyer, Adam L. Kraus, Stephen Giacalone, Joshua N. Wayne, Allison Perrella, Luke Gee. Poma, David R. Ciardi, Karen A. Collins, Giovanni Covon, Zoe L. De Bors, Chelsea X. Huang, John M. Jenkins, Laura Kreidberg, David W. Latham, Samuel N. Quinn, Sarah Seager, Avi Spurrer, Joseph. Dr.. Twicken, Bill Fuller, Roland K. Vandersbeek, Ricardo Yarza and Karl Ziegler, January 10, 2024, Astronomical magazine.
doi: 10.3847/1538-3881/ad1039

This research was supported in part by grants from NASA (HST-HF2-51493.001-A, 21-ASTRO21-0068 and XRP 80NSSC21K0393) and the National Science Foundation (AST-2143763, PHY-2210452 and 1745302).