However, Integral's observations revealed that a slow-spinning neutron star, with an unusually strong magnetic field has likely just begun feeding on material from a neighboring red giant star
Summary: TEHRAN (FNA)- An international team of astronomers has produced the first detailed images of the surface of a giant star
outside our solar system, revealing a nearly circular, dust-free atmosphere with complex areas of moving material, known as convection cells or granules, according to a recent study.
Jim Fuller (Caltech) and colleagues used these changes to study a few dozen red giant stars
that had been monitored for years by the Kepler spacecraft.
The shape and the size of its orbit are also unusual for a planet like Kepler-432b that is revolving around a giant star
. In less than 200 million years, this "red giant" will most likely swallow up the planet.
At issue, explained lead study author and doctoral student Ben Shappee, is the identity of the white dwarf's companion - is it another white dwarf, or a giant star
, or even a star like our sun?
"No giant star
had ever been discovered with copious amounts of dust in its planetary system," Melis says.
Red giant stars
, on occasion, collide with their companion star and that could lead to removal of up to 90 percent of the red giant stars
' mass.A How the star loses so much mass has yet to be explained but the new type of pulsating star discovered by the astronomers could offer up some new clues about stellar collisions.
But does that white dwarf draw material from a Sun-like star, an evolved red giant star
, or from a second white dwarf, or is something more exotic going on.
Astronomers had thought that material ejected by supernovas or giant stars
would come to rest after about 100,000 years, slowed down by shock waves and collisions with other interstellar material.
The researchers say three of the tiny grains they studied formed in the winds of aging giant stars
. Another one apparently came from an especially old star that was poor in heavy elements.
Normally, a white dwarf packs the equivalent of the sun's mass into a ball roughly the size of a modest planet, while neutron stars -- the crushed relics of supernova explosions of giant stars
-- can have similar masses but diameters of 40 kilometers or less.
This old astrophysical mystery may have been solved by very long baseline radio interferometry of four old giant stars
that turn out to have unexpectedly strong magnetic fields.