A Lost 1917 Image Shows the Earliest Evidence of Exoplanets

Image Credit: Carnegie Institution for Science

Even major scientific institutions need to reassess the stuff that’s piled up in their basement every once in a while. The Carnegie Observatories in Pasadena recently did so and found evidence of the earliest observation of a planetary system outside our own.

At the request of Jay Farihi, a University College London researcher searching for material for a journal article, the Carnegie Observatories sent someone down to the basement to hunt for an astronomical plate of the spectrum of a white dwarf star. Recording stellar spectra was the main way 19th century astronomers studied stars’ chemical compositions and classified them.

The Observatories did locate an astronomical plate of the white dwarf called van Maanen’s star, made in 1917 at what was then called Mount Wilson Observatory.

When Farihi examined the plate, he noticed that the spectrum showed heavy elements like calcium and iron—a sign astronomers have recently determined indicates a planetary system. “Polluted white dwarves,” as these white dwarves surrounded by heavy elements are called, have rings of planetary remnants left over from an earlier time. The pull-out box in the image above shows the heavy element calcium. The spectrum itself is the thin black line in the middle of the image.

“The unexpected realization that this 1917 plate from our archive contains the earliest recorded evidence of a polluted white dwarf system is just incredible,” the director of the Carnegie Observatories, John Mulchaey, explained in a press release.

It pays to clean out the basement, kids.