Astronomers Detect Potential Planet in Habitable Zone of Hottest Star Yet
The celestial body, if confirmed, would be the first planet discovered orbiting such a scorching star.
Scientists have identified a potential exoplanet, designated HD 156295 b, within the habitable zone of HD 156295, a star significantly hotter and larger than our sun. This discovery, detailed in The Astrophysical Journal, marks a potential milestone in the search for planets orbiting extreme stellar environments.
HD 156295, located approximately 140 light-years from Earth, has a surface temperature of about 13,500 degrees Fahrenheit, making it substantially hotter than the sun's surface temperature of roughly 10,000 degrees Fahrenheit. The star is also described as being twice the size and nine times more luminous than our sun, appearing bluish-white and visible to the naked eye.
Despite the star's intense heat, HD 156295 b has been found within its habitable zone, the region where conditions might allow for the existence of liquid water. Researchers noted that if confirmed, HD 156295 would be the hottest star ever to host a planet in its habitable zone.
However, the planet itself is not expected to be Earth-like. Preliminary assessments suggest it is a gas giant, potentially six times the size of Jupiter. Its orbit is also considerably farther from its star than Earth's is from the sun, at approximately four times the Earth-sun distance. HD 156295 b completes one orbit around its star every 2,200 days.
The detection of this potential exoplanet involved analyzing data from NASA's Transiting Exoplanet Survey Satellite (TESS), which monitors Delta Scuti stars. These stars pulsate in brightness, acting like cosmic metronomes. The research team examined 16,500 such stars, narrowing their focus to nine star systems, including the one containing HD 156295 b.
Scientists employed a method called pulsation timing, which measures variations in the time it takes for a star's light to reach Earth. This technique helps identify irregularities in a star's cadence that could be caused by the gravitational influence of orbiting bodies, such as planets. The steady pulsation of HD 156295 allowed researchers to detect such anomalies.
The existence of HD 156295 b is currently estimated to have a probability of just over 50%, described as akin to a coin toss. If confirmed, the discovery would be significant, as only a small fraction of known exoplanets orbit luminous and hot A-class stars like HD 15629.