Key Projects

Planets younger than 800 Myr are systematically larger than mature planets, but it remains unclear whether this reflects thermal contraction, photoevaporation, core-powered mass loss, or differences in formation pathway. The key missing observable is mass. Unfortunately radial velocity surveys are strongly limited by the magnetic activity of young host stars, leaving only ~ a dozen planets younger than 800 Myr with any mass constraint.

We propose a 1,890-hour, 3-semester Key Project to determine the empirical mass-radius-age relation for young transiting planets using LCO’s global 0.4–2m network. Our sample includes 55 confirmed and 22 candidate planets in multi-planet systems younger than 800 Myr, including 36 planets below 200 Myr. We will use Transit Timing Variations (TTVs) as an activity-independent mass measurement technique, taking advantage of the high incidence of near-resonant architectures in young systems and the resulting enhanced TTV yield.

Using multi-band LCO photometry, we will validate new candidates, refine radii affected by spot-induced systematics, and measure masses or robust upper limits through photodynamical TTV analysis. For a smaller subset of active systems, we will also provide photometric monitoring to support ongoing radial-velocity campaigns. We will combine all constraints, including non-detections, in a Hierarchical Bayesian analysis to derive the first population-level mass-radius-age relation spanning 10–800 Myr.

A key innovation is our predictive optimization strategy: by propagating posterior distributions from existing Kepler, K2, TESS and other timing data forward as “TTV funnels,” we identify the ~20% of future transit epochs with the highest information content and concentrate LCO time on the observations that most effectively break dynamical degeneracies. Our team already has a fully operational pipeline for transit extraction, variability modeling, and N-body photodynamical fitting, and has generated baseline TTV predictions for the full target sample. In a conservative scenario, this program will more than triple the number of young planets with mass constraints, delivering the first statistically robust test of gas dwarf versus water world formation and mapping how planetary interiors evolve across the most formative stages of planetary history.

Galactic plane transients hold the key to testing a number of underexplored elements of stellar and planetary evolution theory.

Microlensing can measure the masses and orbital separations of planetary (including multi-planet) systems in cool (~1-10 au) orbits, testing predictions of star/planet formation theory. It can also characterize brown dwarf binaries and isolated stellar remnants, testing predictions about the evolution of massive stars.

Our ability to detect transients throughout the Milky Way will dramatically increase over the next year thanks to time domain surveys of the Galactic plane. However, survey data alone is insufficient in cadence and/or wavelength-coverage to characterize, or sometimes even properly classify, these discoveries. Additional data from LCO's flexible and responsive global telescope network is vital to fully realize the science from these discoveries.

This project will characterize >30 planetary and >10 stellar remnant microlensing events per year, and search for multi-planet signatures. Historically, the unpredictable nature of transient follow-up has meant data on events that turn out to be misclassified is neglected; dwarf novae in particular can mimic microlensing. We propose to characterize rather than neglect such targets to maximize the scientific yield with an open community approach to data sharing.

The Global Supernova Project is a worldwide collaboration of more than 200 scientists studying stellar explosions using more than 40 telescopes around the world and in space.  We are studying 500 supernovae over 3 years to add to the 800+ we have already studied.  The primary goal is to use LCO's "always on" network to study supernovae within hours of explosion, which can help reveal the nature of the elusive final stages of stellar evolution.  Another goal is to use supernovae as standard candles to reveal the expansion rate of the universe, and to support future efforts to measure Dark Energy.

We propose a continuation of the Global Supernova Project, a worldwide collaboration of more than 200 astronomers who have studied approximately 1300 supernovae and published 271 papers over the last 12 years. We will observe 500 supernovae with LCO resources, and a subset with 36+ facilities and instruments, spanning X-ray to radio wavelengths. We will study emerging mysterious new supernova subtypes, including fast transients, SNe lcn, and electron capture supernovae. We will further expand on our pioneering work in superluminous supernovae, and our work revealing the progenitors of SNe la, SNe II, and stripped envelope supernovae from observations taken just after explosion. We will also work to improve the use of supernovae in cosmology, improving the comparison sample for missions such as the Nancy Grace Roman Space Telescope, understanding the systematic errors in supernovae, and improving the tools used to standardize them. With large samples of both common and exotic SNe we will break new ground studying luminosity functions, splitting SNe into subsamples by metallicity and other properties, simulating them, and finding outliers that reveal new physics.

The LCO Outbursting Objects Key (LOOK) Project started in 2020 with two main objectives: (1) to use the telescopes of the LCO Network to systematically monitor a sample of Dynamically New Comets (from the Oort cloud) over the whole sky. (2) to rapidly follow up announcements of outbursts and unexpected activity on any small solar system object for confirmation and more detailed characterization. The project has had great success on both of these goals, and its mission has evolved to include: (3) dedicated mini-outburst discovery campaigns for comets with close approaches to the Earth, and (4) rotational studies of long-period comets with cometary CN filters, now globally distributed on the LCO Network. We've also teamed up with the Faulkes Telescope Project's Comet Chasers educational outreach program to provide a source of interesting targets for school children to follow up on and contribute to scientific studies. LOOK, having developed and refined a rapid response to Solar System outbursts, is now very well placed to exploit the start of the Rubin Observatory's Legacy Survey of Space and Time (LSST) to rapidly respond to and characterize outbursts across the Solar System.

We propose the New LCO Outbursting Objects Key Project (New LOOK Project) to exploit the synergy between sky surveys and LCO's rapid response telescope network for Solar System science. Active objects are mass-losing comets & asteroids, primitive objects whose properties reflect the composition and processes that were present in the outer Solar System's protoplanetary disk. However, their properties can change with time, altered by internal and external processes like radiogenic heating, impacts, or insolation-driven surface differentiation. By studying these processes, we can better define the early Solar System's properties and improve comparisons to protoplanetary disks and exoplanetary systems we see today.

The original LOOK Project used the telescopes of the LCO Network to:

1. Systematically monitor a sample of previously discovered Dynamically New Comets (DNCs) over the whole sky at LSST-style cadence to assess the evolutionary state of these distant remnants from the early Solar System,

1. Use alerts from existing sky surveys and amateurs to rapidly respond to and characterize outburst activity in all small bodies, contributing to new insights into outburst processes and the distribution of volatiles across the Solar System.

To build upon our prior success, and advance our knowledge of the evolution of active objects, the New LOOK Project will address two science objectives:

1. Physical characterization of active objects through outbursts. We will use the telescopes of the LCO Network to rapidly respond to and systematically characterize outbursts on comets and asteroids over the whole sky and across a wide range of distances. By studying the onset and evolution of outbursts across the Solar System, we can better understand the physics of outbursts on small bodies and the interior material they excavate. Rapid LCO follow-up in response to outburst alerts from Rubin Observatory and other sky surveys will produce better coverage of outburst evolution than is possible from any single survey. This will provide improved insights into outburst processes and their evolution with time.

1. Rotational studies of bright comets. We will make use of the unique globally distributed nature of the LCO 1-meter telescopes and their set of six permanently available CN narrowband filters to constrain the rotational properties of brighter comets in order to gain insight into physical properties of the nucleus. These properties are known for relatively few comets, and most have been measured far from the Sun when the comet’s activity was low and the nucleus could be directly detected. Narrowband CN imaging is the most effective way of determining rotational properties of strongly active comets, when the nucleus rotation is otherwise obscured by the coma dust. This work will appreciably increase the number of Oort cloud comets with measured rotation periods, enabling meaningful comparison with the short-period comet population.

With the imminent start of Rubin Observatory’s alert stream, and the continued success of existing surveys e.g. ATLAS, PanSTARRS, and ZTF, the New LOOK Project will fill critical capabilities in the time-domain ecosystem for studies of evolving active objects.

We propose a 3-year Key Project to use LCO facilities for the photometric follow-up of transiting exoplanet candidates detected by the TESS mission during its 3rd Extended Mission (September 2025 – September 2028). This proposal is a continuation and evolution of two previous LCO Key Projects (KEY2020B-005 and KEY2023B-005) that have contributed to about 260 peer-reviewed publications and the validation or confirmation of over 350 planetary systems to date.

TESS's large pixel size (21″×21″) means that multiple stars are typically blended in the photometric aperture, resulting in a ~50% false positive rate. Ground-based seeing-limited photometry is essential for identifying the true source of each transit signal. Among all facilities conducting TESS photometric follow-up, the LCO 1m/Sinistro network produces the highest data quality, routinely achieving 200–400 ppm model residuals in 10-minute bins and reliably detecting transits as shallow as 700 ppm.

Our project has two science objectives. The first is advancing the understanding of small planets (≲4 R⊕). The origin of the observed radius valley near 1.6 R⊕ — whether driven by photoevaporation, core-powered mass loss, or a compositional dichotomy between rocky cores and migrated steam worlds — remains an open question that can be addressed by populating the radius-mass diagram with more precisely characterized planets. Recent JWST atmospheric detections on rocky exoplanets further highlight the value of discovering small planets around bright host stars suitable for mass measurement and atmospheric characterization. We expect our observations to lead to the discovery of at least 140 small planets with measurable masses over 3 years.

The second objective focuses on warm Jupiters — gas-giant planets with orbital periods beyond ~10 days. Unlike hot Jupiters, warm Jupiters retain the orbital eccentricity imprints of their dynamical histories, making their eccentricity distribution a diagnostic of formation and migration mechanisms. Furthermore, warm Jupiters lie below the irradiation threshold for radius inflation, providing a baseline for testing interior structure models against measured radii. We will pursue warm Jupiter candidates including duo-transit systems, where TESS observes only two transits separated by a long data gap, requiring ground-based observations to determine the unique orbital period. We also will monitor systems showing transit timing variations (TTVs) to measure planet masses in multi-planet systems. We expect to discover approximately 60 warm Jupiters in 3 years.

We request 1,045 x 1m/Sinistro hours, 480 x 0.35m/QHY600 hours, and 180 x 2m/MuSCAT hours per semester. Additional time will be contributed by LCO site partners, for a total of 1,400 x 1m/Sinistro hours, 800 x 0.35m/QHY600 hours, and 240 x 2m/MuSCAT hours per semester, meaning that the time contributed by LCO site partners will be 40% of the total 0.35m/QHY600 time and 25% of the 1m/Sinistro and 2m/MuSCAT time. Our team includes key members of the TESS Follow-up Observing Program (TFOP), and we have developed automated scheduling, data reduction, and coordination tools that maximize observing efficiency and minimize duplication. All LCO data and results will be uploaded to the ExoFOP-TESS community repository, amplifying the scientific impact of this Key Project well beyond our own team.

We propose to extend our successful LCO AGN Intensive Broadband Reverberation Mapping (IBRM) program in new directions motivated by major advances from our previous LCO Key Projects. These studies demonstrated smoothly increasing optical/UV continuum lags consistent with thin-disc scaling, revealed excess lags near the Balmer jump likely arising from diffuse continuum emission in the broad-line region (BLR), and exposed tensions with standard reprocessing models, including overly large inferred disc sizes and weak optical--X-ray correlations. Together, these results point to the need for new models of AGN central engines. In this project, we move beyond static reverberation signatures to focus on echoes in time: how reverberation mapping (RM) signals evolve as AGN change state. Using LCO’s uniquely intensive multi-band and spectroscopic monitoring, combined with coordinated X-ray, UV, and IR observations from space-based facilities, we will track the evolving interplay between discs, coronae, and BLRs, an approach that is especially timely in the LSST era. Our goals include: (i) a decade-long survey of AGN echo mapping in the local Universe to capture long-term broadband RM evolution; (ii) simultaneous measurements of emitting-region sizes using LCO together with VLTI/MATISSE and GRAVITY+; (iii) exploiting LCO to identify and follow AGN state transitions through changes in their reverberation response; and (iv) using evolving RM signals to test candidates for supermassive black hole binaries.

MAESTRO is a survey of 211 (105) eclipsing binary stars. Two stars that periodically pass in front of each other as seen from Earth. Because we can measure this alignment geometrically, eclipsing binaries let us determine stellar masses, radii, and temperatures directly from physics, with precision better than 1% and without relying on theoretical stellar models. Using the LCO global network of 0.4-m telescopes, MAESTRO observes each target in four wavelengths simultaneously (Sloan u', g', r', i') during eclipse. The different eclipse depths across these bands reveal the individual temperatures of both stars. The resulting catalogue will provide benchmark stars for calibrating upcoming space missions such as ESA's PLATO/ARIEL, help identify oscillation modes in pulsating stars, and detect unseen companions through subtle variations in eclipse timing. The survey runs from 2026B through 2027B with approximately 550 hours of dedicated telescope time.

Detached eclipsing binaries (DEBs) with masses and radii measured to better than 1% are among the most powerful tools in stellar astrophysics, serving as model-independent benchmark stars, calibrators for forthcoming space missions, laboratories for asteroseismology and the detection of circumbinary bodies. We propose MAESTRO (Multi-band Analysis of Eclipsing Stars: Temperatures, Radii, and Orbits), a systematic six-semester multi-band photometric survey of 211 well-characterised DEBs using the Las Cumbres Observatory (LCO) global network of 0.4-m telescopes equipped with QHY600 cameras and Sloan u', g', r', and i' filters. Our sample has been assembled over more than a decade of high-resolution spectroscopic campaigns within the CRÉME project, yielding precise radial velocities and orbital solutions for all targets. The proposed multi-band photometry serves three scientifically interconnected goals. First, we will determine precise, fundamental effective temperatures for both components of DEB via the method of Miller et al. (2020, 2022), which extracts wavelength-dependent flux ratios from simultaneous multi-band eclipse photometry and combines them with broadband catalogue photometry and Gaia parallaxes to yield photometric Teff with precision below 1%, independent of model atmospheres. These measurements establish robust benchmark stars for stellar astrophysics, spectroscopic surveys (Gaia-ESO, GALAH, 4MOST), and space missions. Second, for pulsating DEBs in our sample, the multi-band data enable identification of oscillation modes through wavelength-dependent amplitude ratios, exploiting the known masses and radii from the eclipsing geometry to anchor asteroseismic models of stellar interiors. Third, we will confirm and characterise circumbinary companions through multi-band eclipse timing variations (ETVs), applying wavelength-independence tests to distinguish genuine light-travel-time signals from chromatic astrophysical effects such as the Applegate mechanism, spot-induced timing shifts, and apsidal motion. The programme requests approximately 1100 hours of time-critical observations over six semesters (2026B–2029A), with 211 targets distributed evenly (~35 per semester) based on right ascension visibility across the LCO global network. MAESTRO will deliver a legacy catalogue of unprecedented scope: ~211 DEBs with fully consistent, model-independent masses, radii, Teff, and [Fe/H], enabling population-level tests of stellar evolution models, calibration of empirical colour-temperature relations and isochrone grids, and verification of Gaia parallaxes across a broad range of FGK spectral types.

This project seeks to elucidate the late stages of evolution of massive stars by studying their pulsations. This method of understanding stellar structure, processing, and motion is called asteroseismology and is analogous to how geologists can infer the internal structure of the earth by studying the waves emanating from earthquakes.

We propose to implement a novel method for performing asteroseismology of massive stars by utilizing the Las Cumbres Observatory network's unique capabilities. In particular, we intend to obtain long-duration, multi-site, multi-band observations of 20 Beta Cep stars, tripling the sample of such stars for which full asteroseismic studies have been performed. Our observations will allow us to constrain the mixing, metallicity, and internal rotation for a large sample of massive stars. These parameters are key for solving long-standing questions in massive-star structure and evolution, supernova physics and compact remnant properties. We will select targets already observed by TESS, allowing us to tune our observations to the known oscillation modes of these stars. Our multi-band data will allow us to identify the different modes (not possible with the single-band TESS data alone) - a crucial component for accurate and valuable asteroseismic modeling. This key project will thus combine existing TESS data with the unique capabilities of the Las Cumbres network to make significant progress in our understanding of massive stars, their explosive deaths, and the remnants they leave behind.