HD 47127 is a normal Sun-like star that has some sort of a really weird companion. This star has been studied for about twenty years using the 107” telescope at McDonald Observatory, which means it was being observed on the same telescope Pamela used for her Ph.D. while she was working on her Ph.D. Beyond that random tidbit, over the twenty years it has been observed, researchers have observed variations in the star’s motion consistent with it having a companion of unusual size. 

This companion, or companions, appears to possibly be about one hundred some odd Jupiter masses in size but has the appearance of a standard brown dwarf. The thing is that brown dwarfs aren’t supposed to be this big. The error in the measurements is great enough that it’s possible to kind of match the data with models that have a more normal brown dwarf of more like 67-78 Jupiter masses. But that larger mass, which doesn’t make sense, really fits the data better, and this raises the question is it maybe two brown dwarf stars orbiting around each other as a tight binary? 

We don’t have a good sense of how many brown dwarfs are out there. They are faint, and once they finish their initial burst of nuclear reactions, they spend their life either cooling and fading or shining only in the reflected light of companion stars. If this is a binary brown dwarf pair, it’s the first we’ve found, and it raises the cool possibility that there could be a planet out there, orbiting a Sun-like star, that has twin giants periodically pass across its sky. More data is needed to figure out if this is what’s really out there, but while we wait, can we get space artists to put this together?

More Information

Phys.org article

“The McDonald Accelerating Stars Survey (MASS): Discovery of a Long-Period Substellar Companion Orbiting the Old Solar Analog HD 47127,” Brendan P. Bowler et al., to be published in The Astrophysical Journal Letters (preprint on arxiv.org)