3 New Super-Earths Could Accelerate Our Search for ET Life
Orange dwarfs are intriguing stellar candidates for supporting life, as they’re less active than Red dwarfs, but produce less radiation that Yellow dwarfs.
A new study from an international team of scientists discovered three Super-Earths orbiting a nearby Orange dwarf only 55 light-years away.
The team discovered these planets using a technique called “radial velocity” by using a spectrograph to monitor a star’s changing spectrum as it experiences subtle gravitational tugs from its orbiting bodies.
When searching the cosmos for extraterrestrial life, scientists often go with a “go-with-what-you-know" approach. Unfortunately, when it comes to examples of life flourishing in the universe, we’re working with a sample size of one, but even with this limited dataset, astronomers continue to find compelling star systems that just might be ripe for life.
One of the key criteria that scientists look for is a rocky exoplanet comfortably nestled in its star’s “Goldilocks zone”—an area some particular distance for the host star (it depends on the type) where a world could contain liquid water. Now, scientists using the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph on the Canary Islands have found three potential Super-Earths (rocky planets similar to Earth, but more massive) orbiting a star only 55 light-years away.
In terms of galactic distance, that’s definitely in our Solar System’s neighborhood.
This star, which is uninspiringly named HD 48498, is a K-type main sequence star, also known as an Orange dwarf. It’s a kind of middle sibling between M-type, or Red dwarfs, and G-type stars known as Yellow dwarfs, of which our Sun is a proud member. Some astronomers believe Red dwarfs could be compelling candidates to host life because of their long lifespans (though maybe too many solar flares)—and obviously we know Yellow dwarfs can get the job done—but Orange dwarfs could have them both beat as they’re less active than M-type stars, but produce less radiation than G-types.
According to a new study published in the journal Monthly Notices of the Royal Astronomical Society, these newly discovered have orbital periods of 7, 38, and 151 Earth days. Crucially, the outermost of these three planets is in the Goldilocks zone, meaning the exoplanet is a compelling candidate for extraterrestrial life.
“The discovery of this Super-Earth in the habitable zone around an orange star is an exciting step forward in our quest to find habitable planets around solar-type stars,” Exeter University’s Shweta Dalal, a co-author of the study, said in a press statement. “This discovery highlights the importance of long-term monitoring and advanced techniques in uncovering the secrets of distant star systems.”
These worlds were discovered via the HARPS-N Rocky Planet Search program, which leverages a technique known as “radial velocity” to discover exoplanets. Over the course of a decade, the team collected 190 high-precision measurements that tracked Star HD 48498 small movements as it was tugged by its orbiting bodies. This subtle movement altered the spectrum of light, blueshifting as it moved toward us and redshifting as it moved away. If the study is correct, this would be the closest known system to host Super-Earths around a star that’s very much like our own Sun.
Of course, a planet being in the Goldilocks zone doesn’t guarantee that life will flourish on its surface. Mars, for example, is technically on the far edge of the Sun’s habitable zone and doesn’t host any life at all (at least not that we know of). However, with these three interesting exoplanets now identified, astronomers can turn their gaze on this compelling star system and see what other secrets it might be hiding.
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