Two Studies Catch Dwarf Stars Eating Their Companions

Two separate studies published Monday in Nature Astronomy show dwarf stars consuming objects that orbit them. Scientific American reports the findings.

In one study, Jamie Williams, a Ph.D. student at the University of Warwick in England, and colleagues observed a white star. Its light dims at regular intervals, and the star shows chemical traces of zinc, copper and niobium. Together, the evidence suggests a planet formed after the star died and now has its atmosphere pulled into the star. Williams called that a "rebirth" of a planetary system, according to Scientific American.

"The key takeaway is that planets don't exist in isolation, but their evolution is directly tied to the star they orbit," Williams told Scientific American.

The second study came from Aaron Householder, a graduate student at MIT. His team spotted a red dwarf that is slowly pulling material from a brown dwarf companion. The process could continue for millions of years. Typically a star either ignores its companion or devours it quickly; this steady nibble is new. Householder called it a "happy accident," Scientific American reports.

"We're excited to see if we can find a star eating a planet or maybe even two planets eating each other," Householder told the outlet.

Both studies carry implications for our own solar system. Williams said a planet could form after the Sun dies, in a second generation. Householder's work suggests that the Sun might one day gradually strip Earth's atmosphere rather than consume the planet in one fiery event.

Both findings are based on single observations, so future confirmation is needed. But they add new examples of how stars and planets interact after a star's active lifetime ends.

• brown dwarf
• dwarf stars
• exoplanets
• MIT
• Nature Astronomy
• red dwarf
• University of Warwick
• white dwarf