Chapter 1: The TOI 451 Star System Unveiled

The TOI 451 star system, located approximately 400 light-years from Earth, hosts three exoplanets that were previously unknown to scientists, thanks to the TESS spacecraft.

A young star, TOI 451, moves through a stellar stream recently identified in late 2018, which spans a significant portion of the night sky. The Pisces-Eridanus stream consists of stars that are relatively young, averaging only about three percent of the age of our solar system.

Dr. Elisabeth Newton from Dartmouth College highlights the importance of this discovery: "This system checks many boxes for astronomers. At just 120 million years old and 400 light-years away, it allows us to conduct detailed observations of a young planetary system. The three planets, ranging from two to four times the size of Earth, present exciting opportunities for examining how planetary atmospheres develop."

Join us on Astronomy News with The Cosmic Companion on March 2, where Dr. Newton will discuss this groundbreaking discovery!

Section 1.1: TESS Observations

The TESS (Transiting Exoplanet Survey Satellite) was instrumental in identifying this trio of exoplanets, having been launched in 2018 to survey the entire sky for transiting exoplanets.

From 2019 to 2020, the infrared Spitzer Space Telescope followed up on these observations, although its mission ended in early 2020. Additional data from NASA’s NEOWISE satellite, collected between 2009 and 2011, also contributed to the findings.

The innermost planet is slightly under twice Earth's diameter and completes an orbit around TOI 451 every 46 hours. The middle exoplanet is over three times the size of Earth, with a year lasting just over nine days, while the largest planet, more than four times the size of Earth, circles its star every 16 days.

Section 1.2: Atmospheric Insights

These newly discovered planets orbit much closer to their star compared to our solar system's planets and experience extreme temperatures due to their proximity. The innermost planet, TOI 451 b, is estimated to have surface temperatures around 1,200 °C (2,200 °F), whereas TOI 451 d, the outermost planet, has surface temperatures near 450 °C (840 °F).

Due to their significant mass, researchers believe these planets may retain atmospheres, unlike smaller planets that could lose theirs under intense stellar pressure.

Chapter 2: The Dynamics of Stellar Streams

The star TOI 451 is believed to have two stellar companions located far beyond the orbits of its newly discovered planets. Dr. Newton notes, "The sun in this planetary system closely resembles our own, but it is much younger. By examining these planets alongside others, we can gain insights into planetary formation and evolution."

Stellar streams like the one containing TOI 451 form when groups of stars or small dwarf galaxies are disrupted by gravitational forces, causing them to spread out along their original paths. The Pisces-Eridanus stream currently extends 1,300 light-years and is visible across 14 constellations.

In 2019, a research team led by Jason Curtis from Columbia University studied stars within this stream observed by TESS. Younger stars rotate faster and exhibit darker sunspots compared to older stars, allowing astronomers to gauge their rotational rates.

This investigation revealed that the stream is approximately 120 million years old, significantly younger than previously estimated. This new age aligns with lithium measurements and excess ultraviolet light observed from the stars.

While astronomers have identified around 4,400 exoplanets since the first one was discovered in 1995, the TOI 451 system is only the eighth young planetary system where transiting planets have been observed.

Moreover, Dr. Newton and her team found indications of a potential debris disk within the TOI 451 system, possibly akin to the asteroid belt in our solar system but more diffuse and dust-laden. With the launch of the James Webb Space Telescope, astronomers look forward to studying exoplanet atmospheres in unprecedented detail.

"The planets present excellent opportunities for transmission spectroscopy with the Hubble and James Webb Space Telescopes, allowing us to explore atmospheres that may still be evolving," the researchers state in The Astronomical Journal.

As we embark on this thrilling new era of astronomy, we are set to uncover the mysteries of distant worlds for the very first time.

James Maynard, the founder and publisher of The Cosmic Companion, resides in Tucson with his wife, Nicole, and their cat, Max.