The effect of water and electron collisions in the rotational excitation of HF in comets

Loreau, Jérôme; Fauré, Alexandre; Lique, François

doi:10.1093/mnras/stac2378

Cited by 2 publications

(2 citation statements)

References 34 publications

(30 reference statements)

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“…In the present paper, we provide a new extension of these data sets in order to cover temperatures up to 150 K and transitions between levels up to = 10 for more general use in models. In addition, the new collisional data are used in a simple radiative transfer model of cometary comae (Faure et al 2020;Loreau et al 2022) in order to test their impact on the excitation of CO. We note that since CO-CO is a system of identical molecules, the distinction between 'target' and 'projectile' is artificial. To our knowledge, however, public radiative transfer codes do not allow to treat the internal structure of a target and a projectile on equal footing.…”

Section: Introductionmentioning

confidence: 99%

The excitation of CO in CO-dominated cometary comae

Żółtowski

Lique

Loreau

et al. 2023

Monthly Notices of the Royal Astronomical Society

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An abundance of CO significantly surpassing the abundance of H2O is observed in the comae of comets at large heliocentric distances. In these environments, CO molecules can be the most abundant species and they may be therefore the dominant projectiles inducing collisional excitation of the cometary molecules. It is thus of high interest to investigate the excitation of CO by CO. This article provides a new set of CO–CO collisional rate coefficients for temperatures up to 150 K and for CO rotational levels j1 up to 10. These data are obtained from quantum scattering calculations using the coupled states approximation. They are used in a simple radiative transfer model in order to test their impact on the excitation of cometary CO. Because mutual (de-)excitations of the target and projectile are important, the CO projectile was assumed to be thermalized at the kinetic temperature. We found that the non-LTE regime extends for CO densities in the range 103 − 107 cm−3. We also observed that as soon as the CO/H2O ratio is larger than 70%/30%, the contribution of H2O collisions can be neglected. Similarly, the excitation of CO by CO may be ignored for relatively low CO/H2O density ratios (≤30%/70%). Finally, when the coma is a ∼50%/50% mixture of CO and H2O, the contribution of both colliders is similar and has to be considered.

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Section: Introductionmentioning

confidence: 99%

The excitation of CO in CO-dominated cometary comae

Żółtowski

Lique

Loreau

et al. 2023

Monthly Notices of the Royal Astronomical Society

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“…For cometary applications, BASECOL2023 has been updated with two datasets (Loreau et al 2022) with thermalised rate coefficients for the de-excitation of HF by o/p-H 2 O (7 levels; T = 5-150 K). The calculations use a new 5D PES (Loreau et al 2020) and the statistical approach of Loreau et al (2018).…”

Section: Hf-h 2 Omentioning

confidence: 99%

BASECOL2023 scientific content

Dubernet,

Boursier,

Denis-Alpizar

et al. 2024

A&A

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The global context of making numerous data produced by researchers available requires collecting and organising the data, assigning meaningful metadata, and presenting the data in a meaningful and homogeneous way. The BASECOL database, which collects inelastic rate coefficients for application to the interstellar medium and to circumstellar and cometary atmospheres, meets those requirements. We aim to present the scientific content of the BASECOL2023 edition. While the previous versions relied on finding rate coefficients in the literature, the current version is populated with published results sent by the producers of data. The paper presents the database, the type of data that can be found, the type of metadata that are used, and the Virtual Atomic and Molecular Data Centre (VAMDC) standards that are used for the metadata. Finally, we present the different datasets species by species. As the BASECOL database, interconnected with the VAMDC e-infrastructure, uses the VAMDC standards, the collisional data can be extracted with tools using VAMDC standards and can be associated with spectroscopic data extracted from other VAMDC connected databases such as the Cologne database for molecular spectroscopy (CDMS), the jet propulsion laboratory molecular spectroscopy database (JPL), and the high-resolution transmission molecular absorption database (HITRAN).

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The effect of water and electron collisions in the rotational excitation of HF in comets

Cited by 2 publications

References 34 publications

The excitation of CO in CO-dominated cometary comae

The excitation of CO in CO-dominated cometary comae

BASECOL2023 scientific content

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