Since the discovery of the first exoplanet in 1988, there have been more than 2,000 discovered. But astronomer Walter Adams, the late director of California’s Mount Wilson Observatory, imaged the first evidence of an exoplanetary system back in 1917, according to the Carnegie Institution for Science.
While researching an article regarding planetary systems surrounding white dwarfs for New Astronomy Reviews, University College London’s Jay Farihi asked Carnegie Observatories’ director John Mulchaey to procure an astronomical glass plate that contained the spectrum of van Maanen’s star, a white dwarf. The glass plate was stored within Carnegie’s archives.
Rather than the digital imaging employed by astronomers today, astronomers of yesteryear used glass photographic plates to image the sky and record stellar spectra, which show the light emitted from distant stars. Based on the distribution of starlight, and the spread of the color components, astronomers can learn more about the star’s chemical composition. Additionally, they can tell how the light is affected by stellar objects it passes through before reaching Earth.
Plate in hand, Farihi examined the spectrum and discovered a hitherto unnoticed abnormality in the spectrum’s absorption line, an indicator of the chemical makeup of objects interfering with starlight.
The spectrum indicated that heavier elements, such as calcium, magnesium, and iron were present. Usually, these elements would have disappeared into the star’s interior.
The discovery categorizes van Maanen’s star as a “polluted white dwarf,” a system type in which a vast ring of rocky planetary remains surrounds a star.
“The mechanism that created the rings of planetary debris, and the deposition onto the stellar atmosphere, requires the gravitational influence of full-fledged planets,” said Farihi in a statement. “The process couldn’t occur unless there were planets there.”
Stars similar to the sun become white dwarfs at the end of their lives. In 2013, Farihi discovered a pair of polluted white dwarfs in the Hyades star cluster. The discovery was achieved with NASA’s Hubble Space Telescope. At the time, he described white dwarfs as “blank pieces of paper.”
No planets have yet been detected orbiting van Maanen’s star, or similar systems. However, it’s only a matter of time, according to Farihi.
R&D 100 AWARD ENTRIES NOW OPEN:
Establish your company as a technology leader! For more than 50 years, the R&D 100 Awards have showcased new products of technological significance. You can join this exclusive community! Learn more.