Tidal forces tagged posts

Planets can force their host stars to act younger than their age, according to a new study of multiple systems using NASA’s Chandra X-ray Observatory. This may be the best evidence to date that some planets apparently slow down the aging process for their host stars.

While the anti-aging property of “hot Jupiters” (that is, gas giant exoplanets that orbit a star at Mercury’s distance or closer) has been seen before, this result is the first time it has been systematically documented, providing the strongest test yet of this exotic phenomenon.

“In medicine, you need a lot of patients enrolled in a study to know if the effects are real or some sort of outlier,” said Ni...

‘Shell structures’ are first of their kind found in the galaxy. Nearly 3 billion years ago, a dwarf galaxy plunged into the center of the Milky Way and was ripped apart by the gravitational forces of the collision. Astrophysicists announced today that the merger produced a series of telltale shell-like formations of stars in the vicinity of the Virgo constellation, the first such “shell structures” to be found in the Milky Way. The finding offers further evidence of the ancient event, and new possible explanations for other phenomena in the galaxy.

Astronomers identified an unusually high density of stars called the Virgo Overdensity about ...

This artist’s concept depicts “heartbeat stars,” which have been detected by NASA’s Kepler Space Telescope and others. Credits: NASA/JPL-Caltech

Discovered in large numbers by NASA’s Kepler, heartbeat stars are binary stars that got their name because if you were to map out their brightness over time, the result would look like an electrocardiogram. Scientists are interested in them because they are binary systems in elongated elliptical orbits. This makes them natural laboratories for studying the gravitational effects of stars on each other. In a heartbeat star system, the distance between the two stars varies drastically as they orbit each other. Heartbeat stars can get as close as a few stellar radii to each other, and as far as 10 times that distance during one orbit.

At the point of ...