Empirically Constraining the Spectra of Stellar Surface Features Using Time-Resolved Spectroscopy

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Autori principali: Berardo, David, de Wit, Julien, Rackham, Benjamin V.
Natura: Preprint
Pubblicazione: 2023
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author Berardo, David
de Wit, Julien
Rackham, Benjamin V.
author_facet Berardo, David
de Wit, Julien
Rackham, Benjamin V.
contents Transmission spectroscopy is currently the technique best suited to study a wide range of planetary atmospheres, leveraging the filtering of a star's light by a planet's atmosphere rather than its own emission. However, as both a planet and its star contribute to the information encoded in a transmission spectrum, an accurate accounting of the stellar contribution is pivotal to enabling robust atmospheric studies. As current stellar models lack the required fidelity for such accounting, we investigate here the capability of time-resolved spectroscopy to yield high-fidelity, empirical constraints on the emission spectra of stellar surface heterogeneities (i.e., spots and faculae). Using TRAPPIST-1 as a test case, we simulate time-resolved JWST/NIRISS spectra and demonstrate that with a blind approach incorporating no physical priors, it is possible to constrain the photospheric spectrum to less than 0.5% and the spectra of stellar heterogeneities to within 10%, a precision that enables photon-limited (rather than model-limited) science. Now confident that time-resolved spectroscopy can propel the field in an era of robust high-precision transmission spectroscopy, we introduce a list of areas for future exploration to harness its full potential, including wavelength dependency of limb darkening and hybrid priors from stellar models as a means to further break the degeneracy between the position, size, and spectra of heterogeneities.
format Preprint
id arxiv_https___arxiv_org_abs_2307_04785
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Empirically Constraining the Spectra of Stellar Surface Features Using Time-Resolved Spectroscopy
Berardo, David
de Wit, Julien
Rackham, Benjamin V.
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
Transmission spectroscopy is currently the technique best suited to study a wide range of planetary atmospheres, leveraging the filtering of a star's light by a planet's atmosphere rather than its own emission. However, as both a planet and its star contribute to the information encoded in a transmission spectrum, an accurate accounting of the stellar contribution is pivotal to enabling robust atmospheric studies. As current stellar models lack the required fidelity for such accounting, we investigate here the capability of time-resolved spectroscopy to yield high-fidelity, empirical constraints on the emission spectra of stellar surface heterogeneities (i.e., spots and faculae). Using TRAPPIST-1 as a test case, we simulate time-resolved JWST/NIRISS spectra and demonstrate that with a blind approach incorporating no physical priors, it is possible to constrain the photospheric spectrum to less than 0.5% and the spectra of stellar heterogeneities to within 10%, a precision that enables photon-limited (rather than model-limited) science. Now confident that time-resolved spectroscopy can propel the field in an era of robust high-precision transmission spectroscopy, we introduce a list of areas for future exploration to harness its full potential, including wavelength dependency of limb darkening and hybrid priors from stellar models as a means to further break the degeneracy between the position, size, and spectra of heterogeneities.
title Empirically Constraining the Spectra of Stellar Surface Features Using Time-Resolved Spectroscopy
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2307.04785