Chemical Models of Inner Disks

Abstract

Abstract. In this paper I describe some of the recent advances made in the modelling of chemistry of protoplanetary disks, and in particular, of the inner regions where r < 100 AU. These advances include the treatment of mass-transport processes, the interaction of radiation with chemistry, the augmentation of chemical networks to include isotopic species and their fractionation, and the attempt to connect disk chemistry with solar system bodies like comets. In the spirit of the title of this volume, I also briefly describe what in my opinion are the current challenges facing models of disk chemistry. These include the unification of chemistry, radiation and dynamics, the treatment of gas-grain interaction and the usefulness of observations to discriminate the different models in the literature.

The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC

“…In fact, the CDMS and JPL catalogs were instrumental for the analyses of spectral recordings obtained, e.g., with the Herschel Space Telescope. In addition, data collections, such as the Leiden Atomic and Molecular DAtabase (LAMDA) [4], CASSIS [5], and splatalogue [6,7], draw heavily on the entries of the CDMS and JPL catalogs. Other databases, such as GEISA [8,9] and HITRAN [10], use many data from the CDMS and JPL databases, in particular in their pure rotational parts.…”

“…An early effort to link molecular spectroscopy data (here from the CDMS and JPL catalogs) with collisional data in a virtual observatory compliant environment was undertaken within the BASECOL collisional data base [36,37]. Eventually, this effort led to the Virtual Atomic and Molecular Data Centre (VAMDC) 6 [38], an infrastructure which links further collisional databases, molecular spectroscopy databases in other frequency regions (e.g. databases such as HITRAN [10] or ExoMol [39]), atomic spectroscopy databases, and also kinetic databases such as KIDA [40] and UMIST [41].…”

SpitzerSAGE Survey of the Large Magellanic Cloud. II. Evolved Stars and Infrared Color-Magnitude Diagrams

“…The Infrared Astronomy Satellite (IRAS, Neugebauer et al 1984) revolutionized the study of evolved stars by observing objects with luminous dusty envelopes at long wavelengths. This survey has provided samples of stars in the LMC to be observed in greater detail up to the present, including spectroscopic observations with Spitzer; see Zijlstra et al (2006) and Markwick-Kemper et al (2005). However, IRAS was only sensitive enough to observe the brightest sources in the LMC (Schwering 1989) from which several hundreds of mass-losing evolved star candidates could be identified (Loup et al 1997).…”

“…The SAGE sensitivity and areal coverage of the entire LMC will allow a detailed quantitative derivation of the global mass loss budget from all stellar populations when combined with existing and future mid-infrared spectroscopic observations of the asymptotic giant branch (AGB) stars and supergiants; for example, see van Loon et al (1999), van Loon et al (2005, Markwick-Kemper et al (2005), and Zijlstra et al (2006). Several studies have derived detailed SFHs in the LMC from a variety of field locations and clusters (Holtzman et al 1999;Olsen 1999) using principally optical color-magnitude diagrams (CMDs) and sophisticated stellar models and fitting techniques (e.g.…”

Ion chemistry in the interstellar medium

“…There exist numerous discrepancies in rate constants and branching ratios compiled into chemical databases available to the astrophysical community. A study by Markwick-Kemper (2005) ranked the importance of reactions used in astrochemical models by examining the effect of uncertainties in rate constants and branching ratios. Of the ˜4000 reactions in the UMIST 99 catalog, only ˜1200 reactions have less than 25% uncertainty and ˜2700 reactions have certainty only "within a factor of 2".…”