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New Earth-like planet discovered in Big Dipper constellation

Astronomers recently unveiled the discovery of an Earth-like planet, younger and closer than any previously identified, named HD 63433d.

This exceptionally hot world offers an unparalleled opportunity to study planetary evolution, given its proximity to our planet and a sun-like star.

Melinda Soares-Furtado, a NASA Hubble Fellow at the University of Wisconsin–Madison soon to be an astronomy professor, and Benjamin Capistrant, a recent graduate now studying at the University of Florida, led this extraordinary study.

Their findings, detailed in The Astronomical Journal, were supported by a global team of co-authors.

Soares-Furtado highlights the significance of HD 63433d, stating, “It’s a useful planet because it may be like an early Earth.”

This comparison paves the way for understanding early planetary conditions and evolutionary processes.

Characteristics of Earth-like planet HD 63433d

HD 63433d is the third planet orbiting a star named HD 63433. Its orbit is remarkably short, completing a full revolution around its star every 4.2 days. This proximity has intriguing implications.

“Even though it’s really close-orbiting, we can use follow-up data to search for evidence of outgassing and atmospheric loss that could be important constraints on how terrestrial worlds evolve,” explains Soares-Furtado.

However, she notes, “that’s where the similarities [with Earth] end — and end dramatically.”

The planet is likely tidally locked, meaning one side perpetually faces the star. This results in extreme conditions: one side may reach temperatures up to 2,300 degrees Fahrenheit.

At these temperatures, HD 63433d could possibly host flowing lava, while the other remains in eternal darkness.

HD 63433: The star of the show

The star HD 63433 shares similarities with our sun in size and type but is significantly younger, at roughly 400 million years old.

It’s located about 73 light years away, in the constellation Ursa Major, which includes the Big Dipper.

“On a dark night in Madison, you could see [HD 63433] through a good pair of binoculars,” Soares-Furtado remarks.

HD 63433d’s discovery is a part of the THYME planet-hunting project. Utilizing data from NASA’s Transiting Exoplanet Survey Satellite (TESS), the team initially identified two mini-Neptune-sized planets in 2020.

Continued observations led to the detection of HD 63433d as it transited between its star and the satellite.

What’s next in the study of HD 63433d

The research team, including UW–Madison’s Andrew C. Nine, Alyssa Jankowski, and Professor Juliette Becker, is enthusiastic about the future study of HD 63433d.

Its young, vibrant star is visible from both the Northern and Southern hemispheres, allowing for extensive observation using various instruments like the South African Large Telescope and the WIYN Observatory in Arizona, projects UW–Madison played a role in developing.

The proximity of HD 63433d offers unique opportunities for studying gas escape from the planet and possibly measuring its magnetic field.

Soares-Furtado emphasizes the excitement of this discovery, “This is our solar backyard, and that’s kind of exciting. What sort of information can a star this close, with such a crowded system around it, give away? How will it help us as we move on to look for planets among the maybe 100 other, similar stars in this young group it’s part of?”

This fascinating discovery sheds light on a new world, while opening doors to a deeper understanding of the cosmos, especially regarding young, Earth-like planets.

The full study was published in The Astronomical Journal.


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