The Travels of WINERED Spectrograph

Japan to Chile

Wasatch Photonics volume phase holographic (VPH) gratings are used in telescopes around the world. In this series on astronomical spectrographs, we explore some of the telescopes and instruments in which our gratings are used, and the science they are studying.

Telescope: Various (compatible with any telescope with Nasmyth focus slower than f/11)
- Araki Telescope, 1.3 m, Koyama Astronomical Observatory, Kyoto, Japan (2013-2017)
- New Technology Telescope (NTT), 3.58 m, La Silla Observatory, Chile (2017-2019)
- Magellan Clay Telescope, 6.5 m, Las Campanas Observatory, Chile (2020-present)
Instrument: Warm INfrared Echelle spectrograph to Realize Extreme Dispersion and sensitivity (WINERED)
Current Location: Magellan Clay Telescope, Las Campanas Observatory, Chile

>> WINERED is a Warm INfrared Echelle spectrograph to Realize Extreme Dispersion and sensitivity, developed by the Laboratory of Infrared High-resolution spectroscopy (LiH) at Kyoto Sangyo University for initial use at the 1.3 m Araki Telescope at Koyama Astronomical Observatory. It was relocated to the New Technology Telescope at La Silla Observatory, Chile in 2017⁴, and finally to the Magellan Clay Telescope at Las Campanas Observatory in Chile in 2020, where it awaits new observations post-pandemic.

This dual-mode spectrograph measures the short NIR bands spanning 0.9-1.35 μm with high signal-to-noise ratio. The spectrograph features a novel non-cryogenic, high sensitivity design that can operate in wide-mode for broad spectral coverage (R = 28,000) or hires-modes (R = 80,000) for the Y-band and J-band to observe various astronomical objects such as the fields of stars, the interstellar medium, and the solar system. It uses a classic Echelle grating and a high blazed echelle grating as the primary dispersion element for wide-mode and hires-mode, respectively, employing additional cross-dispersers in the form of three Wasatch Photonics VPH gratings for both modes, with maximum diffraction efficiencies of 86 – 95%³.

High-resolution NIR spectroscopy is able to resolve atomic and molecular lines that evade detection in other wavelength regions, and is used in Doppler searches of exoplanets revolving around red dwarf stars and young stellar objects. It also better at analysis of hard-to-see stars and quasi-stellar objects. While installed at the Araki Telescope, WINERED measured abundances of various heavy metals in giant and supergiant stars^5,6 and identified new absorption lines originating from heavy elements⁷, which will help us better understand the chemical evolution of galaxies. It has also been used to discover new diffuse interstellar bands (DIBs) in the infrared region^8,9, which are believed to be absorption lines by organic molecules in interstellar matter, and to measure weak ¹²CO₂ absorption lines in the sunlit dayside hemisphere of Venus to derive the rotational temperature¹⁰. Explore more research performed using the WINERED spectrograph on the LiH website.

References

Yasui, Chikako, et al. “Warm infrared Echelle spectrograph (WINERED): testing of optical components and performance evaluation of the optical system.” Ground-based and Airborne Instrumentation for Astronomy II. 7014. International Society for Optics and Photonics, 2008.
Otsubo, Shogo, et al. “First high-efficiency and high-resolution (R= 80,000) NIR spectroscopy with high-blazed Echelle grating: WINERED HIRES modes.” Ground-based and Airborne Instrumentation for Astronomy VI. 9908. International Society for Optics and Photonics, 2016.
Ikeda, Yuji, et al. “High sensitivity, wide coverage, and high-resolution NIR non-cryogenic spectrograph, WINERED.” Ground-based and Airborne Instrumentation for Astronomy VI. 9908. International Society for Optics and Photonics, 2016.
Ikeda, Yuji, et al. “Very high-sensitive NIR high-resolution spectrograph WINERED: On-going observations at NTT.” Ground-based and Airborne Instrumentation for Astronomy VII. 10702. International Society for Optics and Photonics, 2018.
D’Orazi, V. et al. “On the Chemical Abundances of Miras in Clusters: V1 in the Metal-rich Globular NGC 5927” The Astrophysical Journal Letters1 (2018): L9.
Kondo, Sohei, et al. “Fe I Lines in 0.91-1.33 μm Spectra of Red Giants for Measuring the Microturbulence and Metallicities” The Astrophysical Journal2 (2019): 129.
Matsunaga, Noriyuki, “Identification of Absorption Lines of Heavy Metals in the Wavelength Range 0.97-1.32 μm” The Astrophysical Journal Supplement Series1 (2020): 10.
Hamano, Satoshi, et al. “Near-infrared Diffuse Interstellar Bands in 0.91-1.32 μm” The Astrophysical Journal2 (2015): 137.
Hamano, Satoshi, et al. “Near infrared diffuse interstellar bands toward the Cygnus OB2 association” The Astrophysical Journal1 (2016): 42.
Sagawa, Hideo, et al. “High dispersion spectroscopy of Venus at 1.0 μm using WINERED at Koyama Astronomical Observatory.” AAS/Division for Planetary Sciences Meeting Abstracts# 48.