Exoplanet discovered around the hottest star in history

Astronomers have opened the door to a unique discovery while analyzing data from the TESS space telescope. According to Ixbt.com, a potential exoplanet has been detected around a white-blue giant star named HD 156295 in the Draco constellation. If this signal is confirmed, this celestial body will become the hottest star in history to have a planet found in its habitable zone. This is reported by Ixbt.com reports.

It turns out that this star, which is 1.67 times more massive than the Sun, has a temperature of approximately 7,767 Kelvin. The star's luminosity is 9.16 times higher than the Sun's, and because it is located only 140 light-years away, it can be seen with the naked eye. The discovered object, named HD 156295 b, is about 6.3 times heavier than Jupiter, orbits the star at a distance of 4 astronomical units, and takes 2,200 days to complete a full orbit.

Scientific approach and new methods

Searching for a planet in this massive star system was no simple task. The commonly used transit method and radial velocities are almost ineffective for A-class subgiants, as their rapid rotation and lack of narrow spectral lines hinder this. Therefore, the research team used the pulsation timing method.

Stars in the Delta Scuti category pulsate with high stability. The gravitational force of a companion object slightly shifts the pulsation phase, and it is through these microscopic delays that the orbit of the second object is reconstructed. The authors have given a confidence rating of approximately 50 percent for this finding, as variations in pulsations can also mimic an orbital signal.

Future observations and prospects

Future steps have also been planned within the scope of the research. TESS data expected in 2027 will extend the observation base to 3,000 days, helping to clarify the existence of the exoplanet. Gaia DR4 astrometry will serve as an additional filter, covering the full orbital period with a 66-month base and is expected to record a 300-microarcsecond shift if the planet truly exists.

Also, within that same sample, 8 more brown dwarf candidates were found, ranging from 25 to 59 times the mass of Jupiter. Six of them fall directly into a statistically rare region known as the "brown dwarf desert." In the future, the PLATO telescope, designed for bright stars, is expected to drastically increase the accuracy of pulsation timing, allowing for the first-ever search for Jupiter-mass companions around hot A-type stars.