A new eye has joined the hunt for exoplanets around nearby stars. The instrument, dubbed SPIRou, has been installed at the Canada-France-Hawaii Telescope (CFHT), where it has achieved first light by snapping the spectrum of the star AD Leonis.

SPIRou is a spectropolarimeter and a velocimeter – the first bit means it observes the optical signatures of polarized light, while the latter part of the instrument is used to watch for wobbles on stars caused by orbiting exoplanets.

SPIRou recorded its first light on April 24, 2018, when it observed AD Leonis, a star located 16 light-years from Earth in the constellation of Leo. The star was chosen because of its high-energy flares, which create clear spectral disturbances that SPIRou can easily pick up.

The instrument continued its first test run over a few nights, gathering the spectra of some 440 stars. SPIRou turned its attention on red dwarfs, the cool stars that make up the majority of our stellar neighbors, as well as a few hotter stars. The images captured by the latter group tend to contain telluric lines, a kind of interference caused by the Earth's atmosphere, which need to be filtered out to really understand the star.

This milestone comes 10 years after the first designs of the instrument were proposed. SPIRou was built and tested in France before being disassembled and shipped to CFHT in Hawaii. Once there, it took another four months to properly install the sensitive instrument on the telescope.

With the first test run complete, SPIRou now has to wait until the (northern) fall before its main program begins. The instrument will look for signs of planetary systems around red dwarfs, as well as study stellar nurseries, regions where new stars are born.

Source: CNRS

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