The NEID spectrometer sheds light on the path to the exploration of exoplanets
“A spectrograph, at its most basic level, divides light into its different colors, or what we call wavelengths,” said Sarah Logsdon, instruments scientist for NEID and assistant scientist at the National Science Foundation. (NSF) BLACKLab, a national ground-based astronomy center headquartered in Tucson, Arizona. “It’s really useful for us because individual atoms and molecules have different emission or absorption at very specific wavelengths. With the NEID, we can measure how much these absorption and emission lines move from their resting position when a planet shoots at its star. The size of this offset allows astronomers to determine the mass of the planet relative to the mass of its star.
A potential challenge for NEID observations is that the stars themselves can change. Hot plasma spurts out from within, cools and falls, while the entire surface vibrates with seismic oscillations. Global and local magnetic fields create darker, cooler star spots and other visible features. All this activity makes it difficult to distinguish between stellar activity and the effects of exoplanets.
However, the Sun serves as a benchmark to better understand stellar activity. In addition to capturing light from the WIYN telescope, the NEID will also receive light from a solar telescope mounted on the roof of the observatory. Over time, this solar data will help scientists identify similar events in their observations of more distant stars. After being processed to help astronomers research the issue of stellar activity, all solar telescope data is released to the public, with the first solar data set released in June 2021.
“The sun shows the way”, noted Suvrath Mahadevan, Professor of Astronomy and Astrophysics at Penn State University and Principal Investigator at NEID. “For decades, the iconic and now disused McMath Pierce Telescope at Kitt Peak has been the primary facility for studying the Sun. The NEID is now the bridge that connects the science of exoplanets to solar observations, the Sun to the stars, and a bridge that connects Kitt Peak’s history to its present and its future.
The NEID team announced the first observations of NEID in January 2020. NEID observed 51 Pegasi, the first Sun-like star to host an exoplanet. The NEID is now available to the scientific community through its guest observation program.
NEID is funded by a partnership between NASA and NSF called NN-EXPLORE (the NASA-NSF Exoplanet Observational Research partnership), which is managed by JPL. The partnership stems from a recommendation in the Decennial survey of astronomy and astrophysics 2010 calling for a program of ground radial speed readings. NEID is the abbreviation for NN-EXPLORE Exoplanet Investigations with Doppler spectroscopy, but the name is also based on a word which roughly translates to “see” in the language of Tohono O’odham Nation, which includes Kitt Peak.
“It was a huge team effort, and I’m really proud of this instrument and what it is able to observe,” said McElwain.
The NEID team is led by Penn State with major partners at the University of Pennsylvania, the University of Arizona, NASA’s Goddard Space Flight Center and the NASA Exoplanet Science Institute at Caltech.
The NEID spectrograph was built at Penn State. NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab) was responsible for modifications to the 3.5-meter WIYN telescope to accommodate the NEID. The design of the telescope port adapter was led by NOIRLab and was built at the University of Wisconsin. Other NEID participants include Carleton College, the National Institute for Standards and Technology, the University of California at Irvine, the University of Colorado, and Macquarie University.
More information about NEID can be found here: https://neid.psu.edu/