Nancy Grace Roman Space Telescope Archives

Primary (circles, ≤ 2 mas) and reserve (triangles, < 5 mas) candidate reference stars plotted in ecliptic coordinates in epoch J2027 and equinox 2027 with colors indicating rankings. The CVZs are shaded in cyan. Only one rank A star is in any of the CVZs, and the overall number of rank A reference star candidates is very low compared to other ranks. If only Rank A stars are viable reference star candidates, science target scheduling for the Roman Coronagraph will likely be restrictive. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) I. Preliminary Vetting and Implications for the Roman Coronagraph and Habitable Worlds Observatory

by Keith CowingNovember 14, 2025November 14, 2025

The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory […]

Roman WFI footprint overlaid on an image of the Rosette Nebula taken from the Second Digitized Sky Survey (DSS-2; B. M. Lasker et al. 1990). Red squares outline the 18 individual WFI detectors. The physical scale bar assumes a distance of 1.4 kpc to the Rosette Nebula. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Predicting Exoplanet Transit Yields In The Rosette Nebula With The Nancy Grace Roman Space Telescope

by Keith CowingNovember 7, 2025November 7, 2025

Young stars host only a small fraction of the known exoplanet population because their photometric variability, magnetic activity, and frequent placement in dense, poorly-resolved regions hamper exoplanet detections.

A representative sample of nine historical events from Table 5. The top row shows nearby (< 4 kpc) events for which a combination of all three mass-distance relations (θE, πE, lens flux) give an unambiguously measured lens mass and distance. The yellow data with error bars shows the best fit result from image-constrained modeling, the blue contours give the posterior distribution (central 39%, 86%, 99%) from pyLIMASS. The middle row shows more distant events (> 4 kpc) for which the estimate of lens mass and distance is still relatively accurate but less precise. The bottom row shows problematic events for which there are degeneracies that remain (MB10328; Vandorou et al. 2025b), or the identification of the lens is dubious (MB11262; Terry et al. 2025b), or the significantly overlapping θE and πE relations result in large errors (OB141760; Rektsini et al. 2025).-- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements

by Keith CowingOctober 20, 2025October 20, 2025

As part of the Galactic Bulge Time Domain Survey (GBTDS), the Nancy Grace Roman Galactic Exoplanet Survey (RGES) will use microlensing to discover cold outer planets and free-floating planets unbound […]

Left: The HWO OS1 ConOps uses a reference star for wavefront sensing to expedite the wavefront control sequence. Center: After the dark hole is created, the observatory is slewed to a science target with an angular roll of +22◦, waits for stabilization, and then an imaging sequence is executed. Right: The observatory is rolled to −22◦, a 40◦ roll in total, waits for stabilization, and then an imaging sequence is executed. Subsequent rolls and periodic wavefront control maintenance visits to the reference star complete the observing scenario. Simulated data based on HWO integrated modeling results provided by John Krist. -- astro-ph.IM

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Habitable World Discovery and Characterization: Coronagraph Concept of Operations and Data Post-Processing

by Keith CowingOctober 6, 2025

The discovery and characterization of habitable worlds was the top scientific recommendation of the Astro2020 decadal survey and is a key objective of the Habitable Worlds Observatory.

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

Roman Coronagraph Instrument Call for White Papers

by Keith CowingJune 16, 2025June 13, 2025

The Nancy Grace Roman Space Telescope (hereafter, Roman) is NASA’s next astrophysics flagship mission. When fully operational in 2027, Roman will provide the astronomical community with an unparalleled opportunity to […]

Yield simulations for transiting planets and asteroseismology using the recommended survey designs. Left: Transiting exoplanet yield relative to the nominal survey as a function of planet radius (x-axis) and host star spectral types (y-axis). Blue bars denote the underguide, and orange bars the overguide survey. Numbers in each panel denote the number of planets expected to be detected in the nominal survey design. Figure credit Robby Wilson (GSFC). Right: Signal-tonoise ratio histogram for asteroseismic detections in red clump stars for the nominal and overguide recommendations. Figure credit: Trevor Weiss (CSULB) and Noah Downing (OSU). -- astro-ph.IM

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

Roman Observations Time Allocation Committee: Final Report and Recommendations

by Keith CowingMay 21, 2025

The Nancy Grace Roman Space Telescope is poised to revolutionize our scientific understanding of exoplanets, dark matter, dark energy, and general astrophysics, including through an innovative community approach to defining […]

Distribution of known exoplanet masses plotted vs. semi-major axis (left) and semimajor axis normalized to the location of the snow-line (right) at asnow = 2.7AU M/MSun (green dashed line). Planets found by the Doppler/RV method (black lines with upward error bars indicating the sin i uncertainty, where i refers to line-of-sight inclination), transits (blue squares), microlensing (red error bar crosses), direct detection, (magenta triangles) timing (green triangles) and transit timing variations (gold diamonds). Small cyan spots indicate Kepler planets and planet candidates without mass measurements. Black letters show the locations of our Solar System's planets. Microlensing discoveries. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Exoplanet Detection With Microlensing

by Keith CowingMay 20, 2025May 20, 2025

Microlensing is the method of exoplanet detection that discovers solar system analog exoplanets.

Size distributions and shapes of the three KCl cloud analogs used in this study. (a) Size distribution of the cloud analogs used here. The mean particle radii and total concentrations are provided in the legend. Our small KCl distribution is produced through wet generation (red), which creates a narrow size distribution. The medium (solid blue) and large (dashed blue) KCl distributions are produced through dry generation, which creates broader size distributions with larger particle number densities. (b) and (c) Scanning electron microscope images of small cubic KCl particles produced using wet generation and large cuboid and irregularly shaped KCl particles produced using dry generation, respectively. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Light Scattering Measurements of KCl Particles as an Exoplanet Cloud Analog

by Keith CowingNovember 5, 2024November 5, 2024

Salt clouds are predicted to be common on warm exoplanets, but their optical properties are uncertain. The Exoplanet Cloud Ensemble Scattering System (ExCESS), a new apparatus to measure the scattering […]

The ratio of a planet’s surface escape velocity squared v2 esc to its orbital velocity squared v2 K as a function of planet’s orbital distance and mass (equation 12). For v 2 esc/v2 K > 1, ejections are more likely than mergers, which we expect towards large orbital distances where the gravitational potential of the central star is shallower and for larger planet mass which can impart greater kinetic energy through scattering. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Status Report

Planet Mass Function Around M Stars At 1-10 au: A Plethora Of Sub-Earth Mass Objects

by Keith CowingOctober 1, 2024October 1, 2024

Small planets (≲1 M⊕) at intermediate orbital distances (∼1 au) represent an uncharted territory in exoplanetary science. The upcoming microlensing survey by the Nancy Grace Roman Space Telescope will be […]

This artist's concept shows the exoplanet K2-33b transiting its host star. Many citizen science projects at NASA invite the public to use transit data to make discoveries about exoplanets. NASA/JPL-Caltech

Astronomy & Telescopes, Citizen Science / Open Science, Education and Outreach, Exoplanets, -moons, -comets, Press Release

How NASA Citizen Science Fuels Future Exoplanet Research

by Keith CowingAugust 15, 2024August 15, 2024

NASA’s upcoming flagship astrophysics missions, the Nancy Grace Roman Space Telescope and the Habitable Worlds Observatory, will study planets outside our solar system, known as exoplanets. Over 5,000 exoplanets have […]

Nancy Grace Roman Space Telescope

CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) I. Preliminary Vetting and Implications for the Roman Coronagraph and Habitable Worlds Observatory

Predicting Exoplanet Transit Yields In The Rosette Nebula With The Nancy Grace Roman Space Telescope

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements

Habitable World Discovery and Characterization: Coronagraph Concept of Operations and Data Post-Processing

Roman Coronagraph Instrument Call for White Papers

Roman Observations Time Allocation Committee: Final Report and Recommendations

Exoplanet Detection With Microlensing

Light Scattering Measurements of KCl Particles as an Exoplanet Cloud Analog

Planet Mass Function Around M Stars At 1-10 au: A Plethora Of Sub-Earth Mass Objects

How NASA Citizen Science Fuels Future Exoplanet Research

Tricorder Tech: New Handheld Device Maps Chemical Composition Using Infrared Light

No Statistically Significant Evidence For A Correlation Between Stellar And planetary Composition

Water Planet Recon: How Accurately Can We Measure Earth Ocean’s Deepest Point?

Webb Reveals A Stunning Panorama Of Star Formation

Deep Learning of SHERLOC Raman Spectra For Facilitating Mars Astromaterial Identification