Astronomers have discovered an exoplanet orbiting an old star for the first time. The last telescope to be found is the Kepler telescope, which is intended to orbit around its growing star until they crush it and destroy it.
By giving us our first glimpse of a planetary system late in its life cycle, this discovery sheds new light on the slow process of planetary decay. Many worlds, including Earth, are predicted to experience interstellar death in the next 5 billion years. Kepler-1568b is an exoplanet with less than 3 million years left.
First author Shreyas Vissapragada said, “We’ve seen evidence of exoplanets moving toward their stars, but we’ve never seen such a planet orbiting an evolved star.”
“For stars like the sun, “evolution” means that they have fused all the hydrogen into helium and moved on to the next stage of their life. In this case, the star has begun to expand into a subgiant. Theory predicts that evolved stars are very efficient at dissipating energy from their planets, and now we can put those theories to the test.”
The inactive exoplanet is known as Kepler-1658b. Its discovery was made possible by the Kepler telescope, a planet-hunting mission that began in 2009. As it is the first candidate for a new exoplanet that Kepler has ever seen, it was given the name KOI 4.01, or the fourth object of interest discovered by Kepler.
KOI 4.01 was initially dismissed as false. Before scientists learned that the data did not match the model, scientists believed they were modeling a Neptune-sized object orbiting a sun-sized star; ten years would pass as it saw the ripples traveling through its star. After scientists showed that the planet and its star were larger than originally thought, the object was officially added as the 1658th object to the Kepler catalog.
Kepler-1658b is a so-called hot Jupiter. Kepler-1658b is only the eighth object in the distance between our Sun and Mercury, which has one of its closest orbits. Kepler-1658b orbits its star in just 3.8 days, as opposed to Mercury’s 88-day cycle.
Kepler-1658b is about two billion years old and is in the last 1% of its life. Its star has reached the point in its stellar life cycle where it has begun to grow, as our Sun was predicted to do, and has entered what astronomers call a phase small. The basic structure of evolved stars, unlike hydrogen-rich stars like our Sun, should easily result in the elimination of tidal energy received from the orbits of the orbiting planets, according to study estimates . As a result, the orbital decay process would accelerate, making human-relevant time exploration much easier.
Orbital decay and collisions are impossible for hot Jupiter and other planets close to their Sun. But because this process is so slow, determining whether exoplanets orbit their star’s orbits has proven difficult. According to the current analysis, Kepler-1658’s orbital period is decreasing by 131 milliseconds (thousandth of a second) every year.
Scientists have observed, “Recognizing this decline took many years of careful observation. The clock started with Kepler and was picked up by the Hale Telescope at the Palomar Observatory in Southern California and, finally, the Transiting Exoplanet Survey Telescope, or TESS, launched in 2018. These three instruments captured transits, the term for when an exoplanet transits the earth the face of its star and causes a very small dimming of the star’s light. Over the past 13 years, the interval between Kepler-1658 transits has decreased slightly but slowly.
“The same action responsible for the daily rise and fall of the Earth’s oceans: ocean currents.”
“The friction distorts the structure of each body, and energy is released as the planets and stars respond to these changes. Depending on the distance between them, their size, and their rate of rotation, these tidal interactions can cause bodies to push against each other – like the Earth and Moon slowly moving forward – or in, like Kepler-1658b to it. star.”
“Many researchers still don’t understand this force, especially in the planetary context, so astronomers are eager to learn more about the Kepler-1658 system.”
Ashley Chontos, Henry Norris Russell Postdoctoral Fellow in Astrophysics at Princeton said, “Although physically, this exoplanet system is very different from our own solar system – our home – it can still tell us a lot about the efficiency of these tidal dispersion processes and whether these planets can live long.”
Reference Journal:
- Shreyas Vissapragada et al. A Possible Effect of the Tidal System of Kepler’s First Planetary System. Astrophysical Journal Letters. DOI: 10.3847/2041-8213/aca47e