{"id":10073,"date":"2024-02-01T00:00:58","date_gmt":"2024-02-01T04:00:58","guid":{"rendered":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/discovery-alert-a-super-earth-in-the-habitable-zone\/"},"modified":"2024-02-01T00:00:58","modified_gmt":"2024-02-01T04:00:58","slug":"discovery-alert-a-super-earth-in-the-habitable-zone","status":"publish","type":"post","link":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/discovery-alert-a-super-earth-in-the-habitable-zone\/","title":{"rendered":"Discovery Alert: A \u2018Super-Earth\u2019 in the Habitable Zone"},"content":{"rendered":"

Discovery Alert: A \u2018Super-Earth\u2019 in the Habitable Zone<\/h2>\n

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4 min read<\/p>\n

Discovery Alert: A \u2018Super-Earth\u2019 in the Habitable Zone<\/h1>\n<\/div>\n<\/div>\n<\/div>\n
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\"On<\/figure>
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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.<\/div>\n
NASA\/JPL-Caltech<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

The discovery:<\/strong>\u00a0A \u201csuper-Earth\u201d ripe for further investigation orbits a small, reddish star that is, by astronomical standards, fairly close to us \u2013\u00a0only 137 light-years away. The same system also might harbor a second, Earth-sized planet.<\/p>\n

Key facts:<\/strong>\u00a0The bigger planet, dubbed TOI-715 b, is about one and a half times as wide as Earth, and orbits within the \u201cconservative\u201d habitable zone around its parent star. That\u2019s 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 \u2013\u00a0a narrower and potentially more robust definition than the broader \u201coptimistic\u201d habitable zone \u2013\u00a0puts 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.<\/p>\n

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\n\t\tThe Planet That Shouldn\u2019t Be There <\/span>
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Details:<\/strong>\u00a0Astronomers are beginning to write a whole new chapter in our understanding of exoplanets \u2013 planets beyond our solar system. The newest spaceborne instruments, including those onboard NASA\u2019s 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.<\/p>\n

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\u2019re 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\u2019s habitable zone. The tighter orbits also mean those that cross the faces of their stars \u2013 that is, when viewed by our space telescopes \u2013 cross far more often. In the case of planet b, that\u2019s once every 19 days, a \u201cyear\u201d on this strange world. So these star-crossing (\u201ctransiting\u201d) planets can be more easily detected and more frequently observed. That\u2019s the case for TESS (the Transiting Exoplanet Survey Satellite), which found the new planet and has been adding to astronomers\u2019 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.<\/p>\n

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\u2019s other properties, including how massive it is and whether it can be classed as a \u201cwater world\u201d \u2013 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.<\/p>\n

Fun facts:\u00a0<\/strong>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.<\/p>\n

The discoverers:\u00a0<\/strong>An international team of scientists led by Georgina Dransfield of the University of Birmingham, United Kingdom, published a paper in January 2024 on their discovery, \u201cA 1.55 R\u2295<\/sub>\u00a0habitable-zone planet hosted by TOI-715, an M4 star near the ecliptic South Pole,\u201d in the journal, \u201cMonthly Notices of the Royal Astronomical Society.\u201d An international array of facilities used to confirm the planet included Gemini-South, Las Cumbres Observatory telescopes, the ExTrA telescopes, the SPECULOOS network, and the TRAPPIST-south telescope.<\/p>\n

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