Astronomers find evidence of a possible second-generation planet

Astronomers report evidence that a gas giant may have formed from material expelled by a dying star and now orbits the star’s remnant, a white dwarf. The interpretation, based on the white dwarf’s unusual chemical composition and changes in its brightness, would make the planet a possible first example of a second-generation planet around a white dwarf. Researchers say the finding remains to be confirmed. The white dwarf, identified as HS 02090832, appears to be drawing material from the nearby planet, according to the research team. The planet may be slightly more massive than Jupiter and is thought to circle its host about once every 4.4 days. At roughly 4 percent of the distance between Earth and the Sun, it is close enough for the white dwarf’s intense ultraviolet radiation to strip gas from its atmosphere, some of which then falls onto the star. The proposed origin rests in part on the white dwarf’s atmospheric chemistry. Researchers identified unusually high amounts of niobium, copper and zinc, elements associated with material expelled by certain stars late in their lives.