A star with planets is like a treasure. Hot Jupiters can make their parent stars appear younger than they really are, according to new results from NASA’s Chandra X-ray Observatory studying multiple systems.
Like humans, many external conditions affect the vitality of a star, and all stars slow down their rotation and bursts of activity as they age. In the past, we have known that the tidal forces of a hot Jupiter can affect the host star, causing the parent star to rotate faster than a star without a hot Jupiter system, and the parent star will therefore be more active, produce more X-rays, and behave like an energetic Young stars.
But calculating a star’s age accurately is challenging, and astronomers have had a hard time determining whether a star is active because it’s being influenced by a nearby planet, or if it’s actually really young.
A team led by astronomer Nikoleta Ilic of the Leibniz Institute for Astrophysics in Germany recently addressed this question by observing multiple binary star systems. In these systems, only one of the stars is orbited by a hot Jupiter, and the hot Jupiter cannot affect the other star, so the researchers can directly use the two stars as the experimental group and the control group to study the behavior differences of stars of the same age.
The results of the analysis of more than 30 systems show that stars with hot Jupiters tend to be brighter in X-ray wavelengths, representing more activity than companion stars without hot Jupiters.
Now we finally have statistical evidence that some planets do influence their parent stars and keep them young.
The new paper is published in the Monthly Notices of the Royal Astronomical Society.
(First image source: Chandra X-ray Observatory)
New technological knowledge, updated from time to time