Simulating RISTRETTO: Proxima b detectability in reflected light

Fuente: arXiv
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Autori principali: Bugatti, Maddalena, Lovis, Christophe, Billot, Nicolas, Blind, Nicolas, Lavie, Baptiste, Turbet, Martin, Chazelas, Bruno, Pepe, Francesco
Natura: Preprint
Pubblicazione: 2025
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author Bugatti, Maddalena
Lovis, Christophe
Billot, Nicolas
Blind, Nicolas
Lavie, Baptiste
Turbet, Martin
Chazelas, Bruno
Pepe, Francesco
author_facet Bugatti, Maddalena
Lovis, Christophe
Billot, Nicolas
Blind, Nicolas
Lavie, Baptiste
Turbet, Martin
Chazelas, Bruno
Pepe, Francesco
contents The characterization of exoplanet atmospheres is one of the key topics in modern astrophysics. To date, transmission spectroscopy has been the primary method used, but upcoming instruments will lay the foundation for advancing reflected-light spectroscopy. The main challenge in this area of research is the high contrast ratio between the planet and its star. RISTRETTO, a high-resolution integral-field spectrograph designed for ESO's VLT, aims to address these limitations through a combination of extreme AO, coronagraphy, and high-resolution spectroscopy. The goal of this paper is to demonstrate the detectability of the temperate rocky planet Proxima b with RISTRETTO, using realistic end-to-end simulations and a specifically developed data analysis methodology. We created high-resolution star and planet spectra, selecting realistic observational epochs and incorporating the predicted performance of the AO and coronagraphic systems. We implemented noise and spectrograph effects through the Pyechelle spectrograph simulator. We then applied a new methodology to isolate the signal of the planet from the stellar one and proceeded to fit several planetary models in order of increasing complexity. We also introduced a method to determine the sky orientation of the stellar spin axis, which constrains the orientation of the planetary orbit for aligned systems. Assuming an Earth-like atmosphere, our results show that RISTRETTO can detect Proxima b in reflected light in about 55 hours of observing time, offering the ability to characterize the planet orbital inclination, true mass, and broadband albedo. In addition, molecular absorption by O$_2$ and H$_2$O can be detected in about 85 hours of observations. These findings highlight the potential of RISTRETTO to significantly advance the field of exoplanetary science by enabling reflected-light spectroscopy of a sample of nearby exoplanets.
format Preprint
id arxiv_https___arxiv_org_abs_2509_07644
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Simulating RISTRETTO: Proxima b detectability in reflected light
Bugatti, Maddalena
Lovis, Christophe
Billot, Nicolas
Blind, Nicolas
Lavie, Baptiste
Turbet, Martin
Chazelas, Bruno
Pepe, Francesco
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
The characterization of exoplanet atmospheres is one of the key topics in modern astrophysics. To date, transmission spectroscopy has been the primary method used, but upcoming instruments will lay the foundation for advancing reflected-light spectroscopy. The main challenge in this area of research is the high contrast ratio between the planet and its star. RISTRETTO, a high-resolution integral-field spectrograph designed for ESO's VLT, aims to address these limitations through a combination of extreme AO, coronagraphy, and high-resolution spectroscopy. The goal of this paper is to demonstrate the detectability of the temperate rocky planet Proxima b with RISTRETTO, using realistic end-to-end simulations and a specifically developed data analysis methodology. We created high-resolution star and planet spectra, selecting realistic observational epochs and incorporating the predicted performance of the AO and coronagraphic systems. We implemented noise and spectrograph effects through the Pyechelle spectrograph simulator. We then applied a new methodology to isolate the signal of the planet from the stellar one and proceeded to fit several planetary models in order of increasing complexity. We also introduced a method to determine the sky orientation of the stellar spin axis, which constrains the orientation of the planetary orbit for aligned systems. Assuming an Earth-like atmosphere, our results show that RISTRETTO can detect Proxima b in reflected light in about 55 hours of observing time, offering the ability to characterize the planet orbital inclination, true mass, and broadband albedo. In addition, molecular absorption by O$_2$ and H$_2$O can be detected in about 85 hours of observations. These findings highlight the potential of RISTRETTO to significantly advance the field of exoplanetary science by enabling reflected-light spectroscopy of a sample of nearby exoplanets.
title Simulating RISTRETTO: Proxima b detectability in reflected light
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.07644