ChromaStarDB: SQL database-driven spectrum synthesis, and more

TL;DR

ChromaStarDB introduces an SQL database approach for spectrum synthesis, enhancing flexibility and speed, while also expanding the capabilities of the ChromaStar and CSS codes for pedagogical and research purposes.

Contribution

The paper presents a novel SQL database implementation for spectrum synthesis, along with major updates to the ChromaStar and CSS codes, improving flexibility, speed, and modeling features.

Findings

SQL database allows flexible transition selection

Spectrum synthesis is fast with large line lists

Code updates improve modeling accuracy and usability

Abstract

We present an alternate deployment of the GrayStarServer (now ChromaStarServer (CSS)) pedagogical stellar atmosphere and spectrum synthesis WWW-application, namely ChromaStarDB (CSDB), in which the atomic line list used for spectrum synthesis is implemented as an SQL database table rather than as a more conventional byte-data file. This allows for very flexible selection criteria to determine which transitions are extracted from the line list for inclusion in the synthesis, and enables novel pedagogical and research experiments in spectrum synthesis. This line selection flexibility is reflected in the CSDB UI. The database extraction is very fast and would be appropriate for the larger line lists of research-grade modeling codes. We also take the opportunity to present major additions to the ChromaStar and CSS codes that are also reflected in CSDB: i) TiO band opacity in the JOLA approximation, ii) Metal b-f and Rayleigh scattering opacity, iii) 2D implementation of the flux integral, iv) Improvement of the N_e convergence, and v) Expansion of the exo-planet modeling parameters, and vi) General improvements to the UI. The applications may be found at the home page of the OpenStar project: www.ap.smu.ca/OpenStars/.