Infrared complex refractive index of astrophysical ices exposed to cosmic rays simulated in the laboratory

Author(s)

Rocha, W. R. M. ; Pilling, S. ; de Barros, A. L. F. ; Andrade, D. P. P. ; Rothard, H. ; Boduch, P.

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 464, n. 1, p. 754-767, JAN 2017.
• Web of Science Citations: 3

Abstract

In the dense and cold regions of the interstellar medium, molecules can be adsorbed on to dust grains to form ice mantles. Once formed, these can be processed by ionizing radiation coming from the stellar or interstellar medium, leading to the formation of several new molecules in the ice. Among the different types of ionizing radiation, cosmic rays play an important role in solid-phase chemistry because of the large amount of energy deposited in the ices. The physicochemical changes induced by the energetic processing of astrophysical ices are recorded in a intrinsic parameter of the matter called the complex refractive index. In this paper, for the first time, we present a catalogue containing 39 complex refractive indices (n, k) in the infrared from 5000 to 600 cm(-1) (2.0-16.6 mu m) for 13 different water-containing ices processed in the laboratory by cosmic ray analogues. The calculation was performed using the NKABS an acronym of the determination of N and K from absorbance data-code, which employs the Lambert-Beer and Kramers-Kronig equations to calculate the values of n and k. The results are also available at the following web site: http://www1.univap.br/gaa/nkabs-database/data.htm. As a test case, H2O: NH3: CO2: CH4 ice was employed in a radiative transfer simulation of a protoplanetary disc to show that these data are indispensable to reproduce the spectrum of ices containing young stellar objects. (AU)

• FAPESP's process: 13/07657-5 - Computational modeling of circumstellar environment of protostars by employing data of bombarded ices with cosmic rays simulated in laboratory.
• Grantee: Will Robson Monteiro Rocha
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/18304-0 - Synthesis and degradation of prebiotic molecular species at planetary atmospheres, comets and interstellar ice analogs
• Grantee: Sergio Pilling Guapyassu de Oliveira
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 15/10492-3 - Study about the chemical evolution of astrophysical ices in the vicinity of young stellar objects employing experimental data in the infrared and computational modeling codes
• Grantee: Will Robson Monteiro Rocha
• Support Opportunities: Scholarships in Brazil - Post-Doctoral