The VSPEC Collection: A suite of utilities to model spectroscopic phase curves of 3D exoplanet atmospheres in the presence of stellar variability

TL;DR

The VSPEC Collection is a set of Python tools designed to simulate spectroscopic phase curves of 3D exoplanet atmospheres considering stellar variability, aiding in the interpretation of observational data.

Contribution

It introduces a modular Python package that combines existing spectral tools with new stellar models to simulate exoplanet observations with stellar activity effects.

Findings

Enables realistic modeling of exoplanet spectroscopic observations

Supports various observational geometries including transits and phase curves

Provides flexible, adaptable tools for stellar and planetary spectral modeling

Abstract

We present the Variable Star PhasE Curve (VSPEC) Collection, a set of Python packages for simulating combined-light spectroscopic observations of 3-dimensional exoplanet atmospheres in the presence of stellar variability and inhomogeneity. VSPEC uses the Planetary Spectrum Generator's Global Emission Spectra (PSG/GlobES) application along with a custom-built multi-component time-variable stellar model based on a user-defined grid of stellar photosphere models to produce spectroscopic light curves of the planet-host system. VSPEC can be a useful tool for modeling observations of exoplanets in transiting geometries (primary transit, secondary eclipse) as well as orbital phase curve measurements, and is built in a modular and flexible configuration for easy adaptability to new stellar and planetary model inputs. We additionally present a set of codes developed alongside the core VSPEC modules, including the stellar surface model generator vspec-vsm, the stellar spectral grid interpolation code GridPolator, and a Python interface for PSG, libpypsg.