Astronomers at the Carnegie Observatory have discovered stored pictures from almost a hundred years ago that show the first-ever evidence of a planetary system beyond our Sun, said the Carnegie Institution of Science on Tuesday.
The new discovery was unexpected. A year ago, Jay Farihi, from the University College London, requested to the Carnegie Observatories an archive containing a spectrum of a white dwarf called van Maanen’s star.
Stellar spectra are registers of the light released by remote stars, including the component colors of light. This data can provide information to astro nomers about the chemical composition of a star, said Carnegie Science in a press release issued Tuesday.
This technique for classifying stars was developed in the 19th century and is still used in the present. Currently, astronomers use digital tools to record stars, however, there are thousands of archives containing glass photographic plates, with stellar spectra from the 20th century.
As requested, the Observatory located the plate from 1917, which had a note saying that the star appeared a bit warmer than our Sun. Farihi, who has published a study about circumstellar debris and pollution at white dwarf stars, discovered something “quite extraordinary” in the plate.
It appears that something called an “absorption line” on the spectrum, showed missing pieces and the presence of heavier elements, including calcium, magnesium, and iron, which should have disappeared into the interior of the van Maanen’s star, given its weight, as explained by Carnegie Science.
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All cues have demonstrated that the van Maanen’s star was, in fact, a polluted white dwarf, a type of system that has been recently discovered by astronomers. According to John Mulchaey, Carnegie Observatories Director, there are more than 250,000 plates stored at the observatories and many of them could unveil new astronomy discoveries.
A theory proposes that white dwarfs like van Maanen’s star, containing heavy elements in their spectra, represent a type of planetary system “featuring vast rings of rocky planetary remnants”, that deposit debris into the stellar atmosphere.
“The unexpected realization that this 1917 plate from our archive contains the earliest recorded evidence of a polluted white dwarf system is just incredible.” Said Mulchaey. “And the fact that it was made by such a prominent astronomer in our history as Walter Adams enhances the excitement.”
Astronomers have not detected any planet orbiting around van Maanen’s star. However Farihi said it is “just a matter of time”.
Source: Carnegie Observatories
https://carnegiescience.edu/node/2019