Density and Refractive Index of Carbon Monoxide Ice at Different Temperatures

Abstract

This paper is intended to study the density and the refractive index of the solid carbon monoxide in the interval 13–28 K to improve our understanding of the dynamics in the astrophysical environments where they are present. A series of deposition experiments have been performed under high vacuum conditions to study the properties of this ice under astrophysical conditions. Ice density has been experimentally calculated at different deposition temperatures of astrophysical interest, which complement the scarce values present in the literature. The refractive index has also been experimentally determined. The data have been used to obtain an experimental relationship between refractive index and density. Values of density are necessary to interpret observations of astrophysical objects or to design irradiation experiments to understand how irradiation affects ices present in these objects. The experimental relationship found between density and refractive index allows us to estimate density from a known refractive index, even for temperatures not reached using our experimental setup.

Experimental Vapor Pressure Determination for C2H4, C2H6, CH3OH, CH4, CO, CO2, H2O, and N2 Molecules for Astrophysical Relevant Temperatures. Implications for the Presence of Volatiles in Kuiper Belt Objects and Trans-Neptunian Objects

“…Although the behavior is more stable between 20 and 30 K in the case of CO, in Luna et al (2022) andGonzález et al (2022) it is possible to check that the results of the density obtained from two different laboratories, the one where the present results have been obtained, and the Interstellar Astrochemistry Chamber, described in Muñoz Caro et al (2010), also agree.…”

“…Figure 2 shows the frequency decrease recorded when CO is deposited at 14 K. When a thickness of approximately 1.9 μm was achieved, the deposition was stopped. For this molecule, this thickness corresponds with a mass of 0.17 mg (Luna et al 2022). As can be observed in Figure 2, the film growth was carried out for around 1400 s, which means that the deposition rate was around 0.12 μg s −1 .…”

A systematic mid-infrared spectroscopic study of thermally processed SO2 ices

“…Indeed, such variations have been systematically measured for other ices (e.g., CH 3 OH and CO) over defined temperature ranges. 58,59 To the best of our knowledge, however, no previous study has undertaken the systematic measurement of the A n and r values of SO 2 ice at different temperatures. In the absence of such a study, the magnitude of the uncertainty introduced into our column density and ice thickness measurements as a result of using A n and r values defined for SO 2 ices deposited at temperatures that differ from those being studied is unclear; although it is important to note that this should not affect the spectroscopic characterisations of the major SO 2 absorption bands discussed in this paper.…”

Bombardment of CO Ice by Cosmic Rays. I. Experimental Insights into the Microphysics of Molecule Destruction and Sputtering

“…The initial column densities of CO ice films for each experiment are listed in Table 1. We assume ρ CO ≈ 0.87 g cm -3 for the initial mass density of CO ice (González Díaz et al 2022;Luna et al 2022), which corresponds to the ice number density n CO ≈ 1.8 × 10 22 cm −3 and a monolayer thickness…”