Even after its mission ended in 2018, data from NASA’s Kepler Space Telescope continues to yield new insights into the vast universe beyond our solar system. Astronomers recently announced the revelation of HD 137010 b, a rocky exoplanet roughly the size of Earth orbiting a distant star 146 light-years away. The finding, published January 27 in The Astrophysical Journal Letters, represents a notable step in the ongoing search for habitable worlds and underscores the enduring legacy of the Kepler mission.
Astronomers have identified a potentially Earth-like exoplanet using data collected by NASA’s now-retired Kepler Space Telescope. The discovery, announced January 27, adds to a growing catalog of planets beyond our solar system and fuels the search for habitable worlds. The ability to find planets resembling Earth is a key step in understanding our place in the universe and the potential for life elsewhere.
The exoplanet, designated HD 137010 b, is a rocky world slightly larger than Earth and orbits a star approximately 146 light-years away. Scientists continue to analyze data from the Kepler Space Telescope, which concluded its mission in 2018, yielding new discoveries years after its decommissioning.
HD 137010 b’s orbital period is estimated to be around one year, similar to Earth’s. It resides near the outer edge of its star’s habitable zone – the region around a star where temperatures could allow for liquid water to exist on a planet’s surface, given the right atmospheric conditions.
Exoplanets are planets orbiting stars other than our Sun. This particular planet is notable because it transits, or passes in front of, its sun-like star from our perspective, and the star is bright and close enough to Earth to allow for further observation. This transit method was key to the discovery.
However, HD 137010 b receives less than a third of the energy and light that Earth receives from the Sun. Its star is cooler and dimmer than our Sun, resulting in an estimated surface temperature of around -90 degrees Fahrenheit (-68 degrees Celsius). For comparison, the average surface temperature on Mars is approximately -85 degrees Fahrenheit (-65 degrees Celsius).
Currently considered a candidate planet, HD 137010 b requires further observation to confirm its planetary status. Astronomers utilize various techniques to identify exoplanets, and this discovery relies on the detection of a “transit” – the slight dimming of a star’s light as a planet passes in front of it.
Even a single transit event allows researchers to estimate the candidate planet’s orbital period. They track the time it takes for the planet’s shadow to cross the star’s surface and compare it to models of the star system. Confirmation requires observing these transits repeatedly to ensure they are caused by a genuine planet.
Observing additional transits will be challenging due to the planet’s Earth-like orbital distance. This distance results in less frequent transit events compared to planets orbiting closer to their stars, making such discoveries more difficult to confirm. The rarity of Earth-like exoplanets is directly related to the difficulty in detecting them.
Despite the potentially frigid climate, researchers suggest that HD 137010 b could potentially harbor a milder climate or even liquid water with a sufficiently dense atmosphere containing a higher concentration of carbon dioxide than Earth’s.
According to models, the planet has a 40% probability of residing within the “conservative” habitable zone and a 51% probability of being within the broader “optimistic” habitable zone. Conversely, there is approximately a 50% chance that the planet falls entirely outside the habitable zone.
The findings were published in The Astrophysical Journal Letters.
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