NASA Announces Discovery of 'Super Earth' in the Habitable Zone

NASA announced on Wednesday the discovery of a "super-Earth" named TOI-715 b, orbiting a tiny, reddish star "fairly close" to our planet - only 137 light-years away.

This newfound exoplanet, potentially the centerpiece of a binary planetary system, beckons exploration due to its unique attributes. TOI-715 b, the larger of the suspected pair, is approximately one and a half times as wide as Earth.

What adds to its allure is its placement within the "conservative" habitable zone around its stellar parent star.

NASA: 'Super-Earth' in Habitable Zone

The habitable zone signifies the region where conditions might be conducive for liquid water to exist on the planet's surface, a crucial factor for sustaining life.

Although suitable atmospheric conditions are imperative for this scenario, TOI-715 b finds itself strategically positioned within the conservative habitable zone, a prospect brimming with potential, according to NASA.

Accompanied by its larger counterpart, there is speculation about the existence of a second planet in this planetary duo. This prospective sibling might closely approximate Earth's size and reside within the same conservative habitable zone.

TOI-715 b orbits a red dwarf, a stellar type smaller and cooler than our sun, known to host rocky planets. Red dwarfs, due to their diminutive size and cooler temperatures, offer a promising avenue for locating habitable planets.

The proximity of these planets to their stars results in more frequent transits, where the planet crosses the star's face, rendering them more accessible for observation.

In the case of TOI-715 b, that's once every 19 days or a "year" on this strange planet, offering scientists a relatively high frequency of observational opportunities.

'Water World'

The discovery finds its roots in the Transiting Exoplanet Survey Satellite (TESS), a space telescope designed to detect these transiting planets.

TESS, launched in 2018, has been steadily expanding the catalog of habitable-zone exoplanets. TOI-715 b now joins the list of such planets, raising prospects for closer scrutiny, particularly by the James Webb Telescope.

The characteristics of TOI-715 b, including its mass and potential classification as a "water world," will determine the feasibility of atmospheric detection, a pivotal aspect of exoplanet exploration.

NASA noted that the confirmation of a second Earth-sized companion would represent a groundbreaking achievement, marking it as the smallest habitable-zone planet identified by TESS thus far, exceeding initial projections.

The discovery was made by an international team of scientists led by Georgina Dransfield of the University of Birmingham in the United Kingdom. They disclosed their findings in a January 2024 paper titled "A 1.55 R habitable-zone planet hosted by TOI-715, an M4 star near the ecliptic South Pole," published in the "Monthly Notices of the Royal Astronomical Society."

This scientific endeavor involved a collaborative effort among various observatories, such as Gemini-South, Las Cumbres Observatory telescopes, the ExTrA telescopes, the SPECULOOS network, and the TRAPPIST-south telescope, affirming the profound importance of this cosmic revelation.

Astronomers define a celestial body as a super-Earth in terms of size, which has to be smaller than Neptune and bigger than Earth. The term "super-Earth" does not necessarily mean that the exoplanet is habitable or similar to our Earth.