[astro-ph.EP] Direct detection and characterization of exoplanet atmospheres via reflected starlight enables probes of composition of mature exoplanet systems (since flux is decoupled from age) at closer separations than via thermal emission (due to observations in visible wavelengths), and even probes of biosignatures.
Candidate targets from Exoplanet Archive in maximum projected skyplane separation vs planet-star flux ratio in Lambertian contrast. Markers correspond to the maximum separation given the mean literature inclination constraint, or at i = 60◦ if no inclination constraint, and at geometric albedo Ag = 0.5, a Jupiter– like albedo. X-axis error bars correspond to max projected separation for i = 10◦ and i = 90◦ where no inclination constraint available. Y-axis error bars correspond to Lambertian contrast at Ag = 0.1 and Ag = 0.7 (Venus-like atmosphere). Markers are color coded by host star Gaia magnitude. Solid markers are for planets with host stars brighter than 5th magnitude; semi-transparent markers are for host stars brighter than 8th magnitude. Histograms show planets in bins of 0.05′′ and 1 dex of contrast. The teal shaded region shows the estimated inner and outer working angle (3λ/D – 20λ/D at 0.63µm; 0.12 – 0.86′′) and the target contrast limit 2×10−9 . The blue line marks the most optimistic Roman CGI contrast curve generated by corgietc (D. Savransky & H. Grigoryan 2025) and retrieved from V. Bailey (2021) at https://github.com/roman-corgi/DI-flux-ratio-plot/. Takeaway: Lazuli’s detection region accesses planets slightly closer than Roman CGI given the larger primary mirror and potential to access shorter wavelength imaging; uncertainties on planet atmosphere and orbital elements move potential targets in and out of detection region. — [astro-ph.EP]
New and upcoming ground and space-based platforms are enabling these observations for the first time. Recently the 3-m Lazuli Space Telescope, from the Eric and Wendy Schmidt Observatory System, was announced, which will be equipped with the ExtraSolar Coronagraph (ESC) designed for reflected light gas giant exoplanet observations in visible wavelengths.
Architectures of target systems. Selected targets are color coded by score, additional known bodies in the system are colored black, with semi-major axis on the x-axis. Planet-mass objects (Mp < 13MJup) are shown by circles, stellar companions are marked with stars. Planet marker size corresponds to (minimum) mass. The optimistic habitable zone (R. K. Kopparapu et al. 2014, Eqn 4 & 5) for each host star is shown in teal. β Pic b & c, HD 160691 b, 47 UMa b, π Men b, υ And d, HD 216437 b, 7 CMa b & c, HD 10647 b γ Cep b, and HD 192310 c are in their star’s HZ, while HD 114783 c, HD 164922 b, HD 128311 c, and HD 192310 c have interior smaller planets in the HZ. — [astro-ph.EP]
In this paper we present 27 known giant exoplanets that make up the first target list for these observations.
Our target list spans ages and temperatures of planets not probed before by direct imaging, but some of which will also be accessible to the Nancy Grace Roman Coronagraph instrument and the ELT-METIS thermal imager, providing comprehensive atmosphere characterization and synergies.
We discuss the science enabled by ESC observations of our target list and enhancements provided by future astrometric and radial velocity measurements.
Properties of the selected targets and their host stars. Top left: Gaia color-magnitude diagram showing the effective temperature (colormap) and spectral type of host stars compared to a sample of Gaia sources (L. A. Pearce et al. 2025b). Most targets orbit AFGK stars, with one (GJ 832 b) orbiting an M dwarf star. Top right: Host star R.A. and Decl. on an Aitoff projection color coded by distance. ϵ Eri is the closest system (3.2 pc) and HD 75302 is the furthest (30.3 pc). Middle: planet equilibrium temperature (Teq, left) and Earth-equivalent instellation flux (right) as a function of mass (circle markers) or Msin i (star markers), color coded by score. For planets without inclination estimates mass uncertainties span literature minimum mass uncertainty to maximum mass (Msin i/ sin(10◦ )). Earth and Jupiter values are marked with teal lines; the magenta line marks the coldest effective temperatures of planets directly imaged to date. Most, but not all, gas giant planet targets are cooler and receive less stellar flux than Earth but more than Jupiter. Bottom: Orbital period (left) and star age (right) as a function of mass as above, color coded by score. On bottom left we show a vertical teal line at the mass of Neptune (∼0.05MJup) and at 13 MJup to illustrate that our targets are all likely gas giants. Many systems have periods shorter than a few years, meaning the planet will likely move significantly during a long observation. Reflected light direct imaging is decoupled from age, and our target list spans systems at all stages of evolution, with β Pic the youngest at ∼0.6 Gyr and HD 219134 the oldest at ∼11 Gyr. — [astro-ph.EP]
Logan A. Pearce, Ewan Douglas
Comments: 31 pages, 16 figures, 2 tables; submitted to AAS Journals; catalog available at https://zenodo.org/records/23548267
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2610.31286 [astro-ph.EP](or arXiv:2610.31286v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2610.31286
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Submission history
From: Logan Pearce
[v1] Thu, 22 Oct 2026 13:51:21 UTC (9,655 KB)
https://arxiv.org/abs/2610.31286
Astrobiology, exoplanet,
