Exoplanet Showcases Strong Influence of its Star HAT-P-2 as detected by Spitzer Space Telescope

Exoplanet Showcases Strong Influence of its Star HAT-P-2 as detected by Spitzer Space Telescope

Astronomers have noticed heartbeat-like vibrations from star HAT-P-2 nearly 370 light years away from us. The exoplanet of star HAT-P-2 is having a strange influence on the star as it approaches close to it in the orbit as noticed by Spitzer Space Telescope. Astronomers noticed that star HAT-P-2 vibrates every 87 minutes and this is possibly caused by an exoplanet that orbits HAT-P-2. The details of the findings of research team have been published in Astronomical Journal Letters.

The exoplanet takes 5.8 days to complete a single orbit but the star pulsates every 87 minutes. The research team said that there is a physical link between the planet and its host star but they aren’t able to explain it at this stage. Astronomers have noticed star-on-star pulsations in the past but this is the first time they have noticed star-planet pulsations. The exoplanet codenamed HAT-P-2b is having an elliptical orbit. It is a massive planet with gravitational pull nearly 24 times that of our planet Earth.

Researchers have collected nearly 350 hours worth of data from Spitzer Space Telescope between July 2011 and November 2015. The research was led by Julien Wit, a postdoc at MIT’s Department of Earth, Atmospheric and Planetary Sciences.

During its closest approach to its host star, exoplanet HAT-P-2b is 4.9 million miles away from HAT-P-2 and at its farthest, it is 15.4 million miles away from host star. Astronomers believe that exoplanet HAT-P-2b absorbs enormous amount of heat when it is near its host star and expels it as it goes far from it. The exoplanet is just 1/100th of the size of its host star and it is quite small to have a strong impact on its host star.

Talking about strange relationship between the exoplanet and its host star, Wit added, “We thought that planets cannot really excite their stars, but we find that this one does. There is a physical link between the two, but at this stage, we actually can’t explain it. So these are mysterious pulsations induced by the star’s companion.”

“It’s a mystery, but it’s great, because it demonstrates our understanding of how a planet affects its star is not complete,” added de Wit. “So we’ll have to move forward and figure out what’s going on there.”

The research paper informed, “The observations show no sign of orbit-to-orbit variability nor of orbital evolution of the eccentric planetary companion, HAT-P-2 b. The extensive coverage allows us to better differentiate instrumental systematics from the transient heating of HAT-P-2 b's 4.5 micron photosphere and yields the detection of stellar pulsations with an amplitude of approximately 40 ppm. These pulsation modes correspond to exact harmonics of the planet's orbital frequency, indicative of a tidal origin. Transient tidal effects can excite pulsation modes in the envelope of a star, but, to date, such pulsations had only been detected in highly eccentric stellar binaries.”