News / Space News

    A ‘Super-Earth’ in the Habitable Zone

    A “super-Earth” ripe for further investigation orbits a small, reddish star that is, by astronomical standards, fairly close to us – only 137 light-years away. The same system also might harbor a second, Earth-sized planet.



    This illustration shows one way that planet TOI-715 b, a super-Earth in the habitable zone around its star, might appear to a nearby observer. Photo: NASA/JPL-Caltech


    The bigger planet, dubbed TOI-715 b, is about one and a half times as wide as Earth, and orbits within the “conservativehabitable zone around its parent star. That’s the distance from the star that could give the planet the right temperature for liquid water to form on its surface.

    Several other factors would have to line up, of course, for surface water to be present, especially having a suitable atmosphere.

    But the conservative habitable zone – a narrower and potentially more robust definition than the broader “optimistic” habitable zone – puts it in prime position, at least by the rough measurements made so far.

    The smaller planet could be only slightly larger than Earth, and also might dwell just inside the conservative habitable zone.

    Astronomers are beginning to write a whole new chapter in our understanding of exoplanets – planets beyond our solar system.

    The newest spaceborne instruments, including those onboard NASA’s James Webb Space Telescope, are designed not just to detect these distant worlds, but to reveal some of their characteristics. That includes the composition of their atmospheres, which could offer clues to the possible presence of life.

    The recently discovered super-Earth, TOI-715 b, might be making its appearance at just the right time. Its parent star is a red dwarf, smaller and cooler than our Sun; a number of such stars are known to host small, rocky worlds. At the moment, they’re the best bet for finding habitable planets.

    These planets make far closer orbits than those around stars like our Sun, but because red dwarfs are smaller and cooler, the planets can crowd closer and still be safely within the star’s habitable zone.

    The tighter orbits also mean those that cross the faces of their stars – that is, when viewed by our space telescopes – cross far more often.

    In the case of planet b, that’s once every 19 days, a “year” on this strange world. So these star-crossing (“transiting”) planets can be more easily detected and more frequently observed.

    That’s the case for TESS (the Transiting Exoplanet Survey Satellite), which found the new planet and has been adding to astronomers’ stockpile of habitable-zone exoplanets since its launch in 2018.

    Observing such transits for, say, an Earth-sized planet around a Sun-like star (and waiting for an Earth year, 365 days, to catch another transit) is beyond the capability of existing space telescopes.

    Planet TOI-175 b joins the list of habitable-zone planets that could be more closely scrutinized by the Webb telescope, perhaps even for signs of an atmosphere.

    Much will depend on the planet’s other properties, including how massive it is and whether it can be classed as a “water world” – making its atmosphere, if present, more prominent and far less difficult to detect than that of a more massive, denser and drier world, likely to hold its lower-profile atmosphere closer to the surface.

    If the possible second, Earth-sized planet in the system also is confirmed, it would become the smallest habitable-zone planet discovered by TESS so far. The discovery also exceeded early expectations for TESS by finding an Earth-sized world in the habitable zone. (NASA)

    FEBRUARY 5, 2024



    YOU MAY ALSO LIKE

    Planet more than 13 times as massive as Earth orbits the 'ultracool' star LHS 3154.
    On Jan. 19, 2024, at 10:20 a.m. EST, the JAXA (Japan Aerospace Exploration Agency) Smart Lander for Investigating Moon (SLIM) landed on the lunar surface.
    Researchers have discovered the oldest black hole ever observed, dating from the dawn of the universe, and found that it is ‘eating’ its host galaxy to death.
    Researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, have discovered X-ray activity that sheds light on the evolution of galaxies.
    Infrared emission from methane suggests atmospheric heating by auroral processes.
    Researchers may have identified the missing component in the chemistry of the Venusian clouds that would explain their colour and 'splotchiness' in the UV range, solving a longstanding mystery.

    © 1991-2024 The Titi Tudorancea Bulletin | Titi Tudorancea® is a Registered Trademark | Terms of use and privacy policy
    Contact