Even though the operational life of the Kepler Space Telescope, both the main mission and the follow on K2 mission, has come to an end, the results are still being examined and are continuing to amaze. NASA announced on Wednesday that the Kepler turned its attention to a white dwarf star called WD 1145+017 located 570 light years away in the constellation Virgo.
As usual, Kepler measured the dips in brightness coming from the white dwarf that indicates the presences of a planet passing between it and Earth. The space telescope found a planet, as well as something else that was strange and spectacular all at once, as Andrew Vanderburg, a graduate student from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts explained in a new paper published in Nature.
“A research team led by Vanderburg found an unusual, but vaguely familiar pattern in the data. While there was a prominent dip in brightness occurring every 4.5 hours, blocking up to 40 percent of the white dwarf’s light, the transit signal of the tiny planet did not exhibit the typical symmetric U-shaped pattern. It showed an asymmetric elongated slope pattern that would indicate the presence of a comet-like tail. Together these features indicated a ring of dusty debris circling the white dwarf, and what could be the signature of a small planet being vaporized.”
The upshot is that WD 1145+017 is tearing the planet apart due to its immense gravity. The scientists examining the data found some more evidence that this catastrophe was taking place 570 years ago when the light left the star on its way to Earth.
“Due to intense gravity, white dwarfs are expected to have chemically pure surfaces, covered only with light elements of helium and hydrogen. For years, researchers have found evidence that some white dwarf atmospheres are polluted with traces of heavier elements such as calcium, silicon, magnesium, and iron. Scientists have long suspected that the source of this pollution was an asteroid or a small planet being torn apart by the white dwarf’s intense gravity.”
Sure enough, it looks like that these heavier elements are polluting the atmosphere of WD 1145+017, just as theory predicts.
As Space.com notes, white dwarfs are what many stars become at the end of their lives. Small to medium-sized stars, such as the sun, swell up into red giants. Then they shed their outer layers and collapse into white dwarfs, about the size of the Earth but with the mass and gravity of the sun. By this time, no hydrogen fusion is taking place. Most white dwarves eventually burn themselves out, becoming black dwarfs, burnt out husks of their former selves.