EXOSIMS Archives

All plot facets identical to Figure 5. Simultaneous characterization of H2O and O2. Detector noise and thermal emission are included. Shorter wavelengths are preferred for dual detection, but result in lower yields. -- [astro-ph.EP]

Possible Observational Survey Strategies to Maximize Exoplanet Yields: A Report from the Survey Strategies Task Group in the Exoplanet Science Yields Working Group

by Keith CowingSeptember 24, 2026September 24, 2026

[astro-ph.EP] We present a variety of possible observational sequences from planet detection to characterization (i.e., survey strategies) for the initial exoEarth detection and characterization survey phase of the Habitable Worlds […]

Imaging & Spectroscopy

The Science Potential of Characterizing Gas Giant Exoplanets with HWO

by Keith CowingSeptember 23, 2026September 23, 2026

[astro-ph.EP] With the ability to directly image Earth-like exoplanets and search their atmospheres for biosignatures, the upcoming Habitable Worlds Observatory (HWO) will also collect high signal-to-noise ratio (S/N) reflected-light photometry […]

[LEFT]: Schematic of the star–planet–observer geometry defining the phase angle α, measured between the star–planet and planet–observer directions. The hemisphere of the planet facing the star is fully illuminated (gold) at all times, while the opposite hemisphere remains in shadow. The observer sees only the portion of the illuminated hemisphere that is visible at a given α, with full illumination visible only at α = 0◦. [RIGHT]: Illustration of planetary phases along an edge-on orbit, with the star at the center and the observer direction indicated below the orbit. Although the star-facing hemisphere remains illuminated throughout the orbit, the visible fraction of this hemisphere changes with phase angle. Full phase occurs at α = 0◦, quadrature at α = 90◦, and new phase at α = 180 , with gibbous and crescent phases spanning the intermediate ranges. -- [astro-ph.EP]

Astronomy & Telescopes

The Impact of Planetary Phase Functions On Exo-Earth Detectability With EXOSIMS

by Keith CowingAugust 6, 2026August 7, 2026

[astro-ph.EP] The under-development NASA Habitable Worlds Observatory (HWO) aims to provide breakthroughs in exoplanet science, yet the most effective approaches to modeling the detection and characterization of potentially Earth-like worlds […]

Example mission schedule for a 5 year mission, a 6.5 m inscribed aperture, one required characterization, and FoR of 75◦. The mission detected 34 EECs and characterized 20 of them. The bottom row of the figure shows all blind observations of stars without a detected EEC, with each observation’s opacity representing the completeness of the observation. All other rows show observations of an EEC that was detected during the course of the mission. The black bars indicate that the star was blocked by the FoR constraint. Each detection and characterization observation includes a line showing the duration of the observation. -- astro-ph.IM

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Understanding HWO’s Field of Regard and Characterization Requirement Trade Space with a Dynamic Observation Scheduling Algorithm

by Keith CowingApril 28, 2026April 28, 2026

The Habitable Worlds Observatory (HWO) aims to image and characterize at least 25 ExoEarth candidates (EECs). Achieving this goal requires a detailed understanding of the observatory’s design trade space, including […]