Gas-Phase Spectra of MgO Molecules: A Possible Connection from Gas-Phase Molecules to Planet Formation

TL;DR

This paper investigates the gas-phase spectra of MgO molecules, proposing their potential as probes for detecting mineral formation regions in planet-forming disks through specific vibrational transitions.

Contribution

It provides high-level quantum chemical analysis of MgO monomer, dimer, and trimer spectra, identifying key vibrational features relevant for astrophysical observations.

Findings

Identified characteristic vibrational transitions at 12.5 μm, 15.0 μm, and 16.5 μm for MgO species.

Suggested these spectral features can indicate mineral formation in protoplanetary disks.

Proposed observational strategies for detecting MgO molecules in star-forming regions.

Abstract

A more fine-tuned method for probing planet-forming regions, such as protoplanetary discs, could be rovibrational molecular spectroscopy observation of particular premineral molecules instead of more common but ultimately less related volatile organic compounds. Planets are created when grains aggregate, but how molecules form grains is an ongoing topic of discussion in astrophysics and planetary science. Using the spectroscopic data of molecules specifically involved in mineral formation could help to map regions where planet formation is believed to be occurring in order to examine the interplay between gas and dust. Four atoms are frequently associated with planetary formation: Fe, Si, Mg, and O. Magnesium, in particular, has been shown to be in higher relative abundance in planet-hosting stars. Magnesium oxide crystals comprise the mineral periclase making it the chemically simplest magnesium-bearing mineral and a natural choice for analysis. The monomer, dimer, and trimer forms of (MgO)_n with n = 1 - 3 are analyzed in this work using high-level quantum chemical computations known to produce accurate results. Strong vibrational transitions at 12.5 {\mu}m, 15.0 {\mu}m, and 16.5 {\mu}m are indicative of magnesium oxide monomer, dimer, and trimer making these wavelengths of particular interest for the observation of protoplanetary discs and even potentially planet-forming regions around stars. If such transitions are observed in emission from the accretion discs or absorptions from stellar spectra, the beginning stages of mineral and, subsequently, rocky body formation could be indicated.