Astronomers have recently identified a new exoplanet, HD 137010b, orbiting the nearby K dwarf star HD 137010, following the detection of a single shallow transit in archived data from NASA’s Kepler Expansion K2 mission.
HD 137010b is estimated to be 6% larger than Earth, with surface temperatures akin to those of Mars, possibly dipping below -70 degrees Celsius. Image credit: NASA/JPL-Caltech/Keith Miller, California Institute of Technology and IPAC.
HD 137010 is classified as a K3.5V dwarf star located approximately 146 light-years away in the constellation Libra.
This star’s age ranges between 4.8 billion and 10 billion years, and its low magnetic activity reflects its status as an old, relatively calm star.
Commonly referenced as BD-19 4097, HIC 75398, 2MASS J15242123-1944215, or TYC 6179-1111-1, HD 137010 has an apparent magnitude of 10.1 and is recognized as one of the brightest stars hosting an Earth-sized planet in temperate orbits.
The new exoplanet, designated HD 137010b, was observed during K2 Campaign 15 when NASA’s Kepler Space Telescope monitored its parent star for about three months in 2017.
“Most Earth-sized planets discovered in the habitable zone orbit red dwarfs, which are smaller and dimmer than the Sun,” explains lead author Astronomer Alexander Venner from the University of Southern Queensland.
“Concerns arise regarding these planets losing their atmospheres due to intense radiation from their host stars, rendering them uninhabitable for known life forms.”
“However, HD 137010b’s star shares characteristics more closely aligned with the Sun, increasing the likelihood that a stable atmosphere could be retained, according to current theoretical models.”
In their study, Venner and colleagues analyzed K2 data, light curves from nearby stars, archival images, and radial velocity measurements to clarify the nature of the transit signal, which lasted roughly 10 hours.
These evaluations strongly suggest that the observed transit is astrophysical and not a result of background interference, eclipsing binaries, or solar-system debris.
Astronomers have determined that the planet’s radius is approximately 1.06 times that of Earth based on the transit depth.
Considering the transit’s duration and the star’s properties, the orbital period of HD 137010b is estimated to be around 355 days.
At its distance from the host star, HD 137010b is estimated to receive about 29% of the stellar flux that Earth obtains from the Sun, placing it near the outskirts of the star’s habitable zone.
“If HD 137010b has an atmosphere similar to that of Earth or Mars, it could experience temperatures colder than Antarctica,” noted Dr. Venner.
“However, if the atmosphere thickens, conditions could warm up sufficiently for liquid water to exist, creating a potentially viable environment for life.”
“Current astronomical instruments are unable to fully characterize this newly discovered planet, but it stands out as a primary candidate for future radial velocity tools aimed at detecting Earth-like analogs.”
“Upcoming space missions, like NASA’s Habitable World Observatory, could also provide images of HD 137010b.”
This discovery is detailed in the following article: paper published in Astrophysics Journal Letters.
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Alexander Venner and others. 2026. A cool Earth-sized planet candidate orbiting a K2 magnitude K-dwarf star. APJL 997, L38; doi: 10.3847/2041-8213/adf06f
Source: www.sci.news
