TOI-715b: The “Super-Earth”

Blog Credit: Trupti Thakur

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TOI-715b: The “Super Earth”

 

American space agency NASA has discovered a “super-Earth” planet, dubbed TOI-715 b, that could potentially support life. It is located 137 light-years away and was found by NASA’s planet-hunting Transiting Exoplanet Survey Satellite (TESS) mission. The super-Earth is around one and a half times as wide as Earth and orbits a smaller, cooler red dwarf star. It completes a full orbit in just 19 days.

Characteristics of Planet TOI-715b

The planet TOI-715 b resides within the star’s “conservative habitable zone,” meaning liquid water could potentially exist on its surface given the right atmospheric conditions. While several factors must align for surface water, including a suitable atmosphere, the conservative habitable zone makes conditions ripe for further investigation. NASA notes the planet could be slightly larger than Earth and may be a “water world,” making its atmosphere more prominent.

Properties of Parent Star

The super-Earth orbits a red dwarf star, which is smaller and cooler than our Sun. Red dwarfs are known to host small, rocky worlds in very close orbits compared to planets around Sun-like stars. But due to cooler temperatures, these tight orbits can remain safely in the habitable zone. More transits also occur due to tight orbits, enabling better detection and study of planets.

Follow-up Plans to Study Viability

NASA plans further scrutiny of TOI-715 b by the James Webb Space Telescope, which will characterize the planet based on additional properties. Much depends on the planet’s mass, whether it has an atmosphere, and any water content. These factors impact both habitability and the ability to study its atmosphere from Earth-based telescopes if present.

Earth Like Planets

While Earth is the only known place harboring life, estimates of habitable zones and discoveries of thousands of exoplanets suggest there may be many more habitable places in the Universe. Based on Kepler data, there could be 40 billion Earth-sized planets in habitable zones of Milky Way stars, including 11 billion orbiting Sun-like stars. The nearest such potentially habitable exoplanet may be just 12 light-years away. As of 2024, more than 60 potentially habitable exoplanets have been confirmed, though more await discovery.

About Transiting Exoplanet Survey Satellite (TESS)

Transiting Exoplanet Survey Satellite (TESS) is a NASA mission designed to search for exoplanets or planets around other stars. The mission was launched in 2018 and has made significant progress so far. Its mission objective is to discover new planets that periodically block part of the light from their host stars, events called transits. TESS has identified over 5,000 candidate exoplanets, 173 of which have been confirmed. TESS has found a number of rare exoplanet discoveries early like TOI 700 d, a potentially habitable Earth-sized world; AU Mic b, a nearby Neptune-sized planet; and LTT 9779b, a planet slightly bigger than Neptune with two suns.

The discovery of a nearby “super Earth” has astronomers raring to learn more about the large planet – particularly whether it has the conditions to support life.

Observed orbiting a small, reddish star just 137 light-years away from Earth, the planet is located in what scientists call the habitable zone, an area of the cosmos where planets have the potential to harbor water. The planet dubbed TOI-715 b, which is about 1½ times as wide as Earth, is just the latest exoplanet astronomers have observed and theorized could support life.

The same system where an international team of scientists observed the planet also might harbor a second, Earth-sized planet, NASA said in a news release. If this theoretical second planet in the system is confirmed, it would become the smallest habitable-zone planet discovered by TESS, NASA’s exoplanet-detecting satellite.

Georgina Dransfield, an astronomer at the University of Birmingham in the United Kingdom, led the team of scientists, who used an array of facilities housing powerful space telescopes to make their findings, which were published in January in the academic journal Monthly Notices of the Royal Astronomical Society.

What is the habitable zone?

Star-orbiting exoplanets beyond our solar system have the potential to support life if they are located in the habitable zone.

In this region, water could remain in liquid form and pool on the planet’s surface, providing a key ingredient for life to flourish.

But sustaining life is a finicky, temperamental business. In a nod to the classic fairy tale, astronomers even refer to habitable zones as “Goldilocks’ zones” because conditions have to be just right – neither too hot nor too cold – for life.

What do we know about this ‘super Earth?’

Telescope arrays on the ground and instruments traveling through space are only just beginning to give astronomers a full understanding of exoplanets that exist beyond Earth’s solar system.

Just last week, NASA unveiled images captured by its spaceborne James Webb Space Telescope of spiral galaxies brimming with stars and even supermassive black holes.

The technology is not simply designed to detect these distant worlds but to also reveal the characteristics of their atmospheres that could offer clues about the presence of life. Occasionally, astronomers are even able to learn more about previously discovered planets, such as one discovered in 2015 that was only recently found to be a possible life-supporting ocean world.

NASA said that planets such as the recently discovered TOI-715 b represent humanity’s best bet of finding habitable planets.

Because it orbits so close to its parent red dwarf star – which is smaller and cooler than our sun – a year on the strange world is equal to 19 Earth days, NASA said. That rapid orbit makes it easier for astronomers to detect and more frequently observe such planets as compared to Earth, which of course takes 365 days between transits.

Astronomers hope to use the Webb telescope to make further observations about the super Earth to determine whether life could – or even does – exist upon its surface.

 

 

 

Blog By: Trupti Thakur