This project aims to formulate, design, build and test a versatile, high-efficiency, low-resolution spectrograph to function as the G-CLEF exposure meter. G-CLEF, the first-generation Giant Magellan Telescope’s (GMT) instrument, is a state-of-the-art, high-resolution, echelle spectrograph for the GMT, expected to be completed for the telescope’s first light. The exposure meter plays a vital role for adjusting barycentric corrections of Doppler radial velocity (RV) by accounting for Earth’s chromatic atmospheric influences. Its significance becomes pronounced in Extreme Precision RV (EPRV) measurements, where the atmosphere’s wavelength dependency contributes to errors at the scale of tens of centimeters per second, the same level of precision required for detecting Earth-analog planets orbiting stars similar to the Sun, aligning with one of the primary scientific objectives of G-CLEF. This paper details the optical and mechanical designs, grounded in the principal requirements that have been previously validated through design trade-off analysis and performance simulations. Additionally, assembly and test phase of the exposure meter prototype are described together with the results that led to the validation of the design.
The discovery of a fair sample of Earth-analogues (Earth 2.0’s), i.e. rocky, Earth-mass exoplanets orbiting a Solar-type star in that host star’s habitable zone, and a subsequent search of evidence of bioactivity on those Earth 2.0’s by the detection of biogenically produced molecules in those exoplanetary atmospheres, are two of the most urgent observational programs in astrophysics and science in general. To identify an Earth 2.0, it is necessary to measure the reflex motion radial velocity amplitude of the host star at the 10 cm/sec level, a precision considerably below that which is currently achievable with existing instruments. The follow-on project to search for the biomarkers in an Earth 2.0’s atmosphere may require an effective planet/star contrast of 10-10, again well below the currently achievable level. In this paper, we discuss technical innovations in the implementation of the GMT-Consortium Large Earth Finder (G-CLEF) spectrograph that will enable these observational objectives. We discuss plans to operate G-CLEF at the Magellan Clay telescope with the MagAO-X adaptive optics system and subsequently with GMagAO-X at the Giant Magellan Telescope (GMT).
This project aims to formulate, design , build and test a versatile, high-efficiency, low-resolution spectrograph to function as the G-CLEF (GMT-Consortium Large Earth Finder) exposure meter. G-CLEF, the first-generation Giant Magellan Telescope's (GMT) instrument, is a state-of-the-art, high-resolution, echelle spectrograph for the GMT, expected to be completed for the telescope's first light. The exposure meter plays a vital role for adjusting barycentric corrections of Doppler radial velocity (RV) by accounting for t Earth's chromatic atmospheric influences. Its significance becomes pronounced in Extreme Precision RV (EPRV) measurements, where the atmosphere's wavelength dependency contributes to errors at the scale of tens of centimeters per second, the same level of precision required for detecting Earth-analog planets orbiting stars similar to the Sun, aligning with one of the primary scientific objectives of G-CLEF. This paper explores the scientific motivation in detail, describes the designs trade-off analysis and the performance simulations aiming to achieve 1cm/s precision on EPRV measurements and outlines the resulting principal parameters derived from these analyses.
This paper describes the deployment of the GMT-Consortium Large Earth Finder (G-CLEF) at the Clay telescope, one of the two Magellan telescopes, in late 2025, moving to the GMT in 2030. G-CLEF is a fiber-fed, ultra-high stability optical band echelle spectrograph designed for extremely precise stellar radial velocity measurement. On the Magellan Clay telescope, G-CLEF will take spectra with resolution up to ~300,000, fully resolving molecular spectral features and opening totally new discovery space for exoplanet atmosphere composition studies. G@M will also be coupled to the Magellan extreme adaptive optics facility, MagAO-X which will allow it to spatially resolve several exoplanets from their host stars. We provide a system description of the G@M instrument as it will be configured at Magellan. A top-level review of optomechanics, electronics and control systems follows, as well as a description of several risk-reduction exercises the team has undertaken.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.