Malalo O Ka Lani Maunakea (The Skies Above Maunakea)

Leilehua Yuen

Hawaiʻi Culture and Language Resident

Gemini Observatory

Hawaiʻi Culture Resident at Gemini Observatory, Leilehua Yuen, will share some insights on our views of the night sky from a traditional Hawaiian perspective. Her current work involves research into old texts and newspapers regarding astronomy practiced by our kūpuna (elders), producing monthly Hawaiian Skies articles and a compilation of stories to expand the IAU’s 88 constellations. Learn more about Leilehua from her stories listed on the Maunakea Observatories’ website.

Link 1: Welcome Leilehua Yuen, Gemini Observatory’s Hawaiʻi Culture and Language Resident

Link 2: Hawaiian Skies: Hikikauʻelia 2026

Protoplanetary Disk Chemistry as a Window into Planet Formation

Charles Law

NHFP Sagan Fellow

University of Virginia

Website

Planets are born in dusty, gas-rich disks around young stars, and the architectures, atmospheres, and potential habitability of exoplanetary systems reflect the conditions within these birth environments. In this talk, I will show how recent advances with facilities such as ALMA and JWST are transforming our ability to probe the structure, composition, and chemistry of protoplanetary disks in unprecedented detail. These observations reveal disks that are far from simple but are instead rich in gas and dust substructures that play a key role in shaping how and where planets form. I will also highlight our efforts to use molecular line emission to trace the earliest stages of this process, providing a new pathway to directly identify young protoplanets still embedded in their natal disks. Finally, I will look ahead to how the upcoming wideband era of radio astronomy is poised to open new frontiers in disk chemistry, planet formation, and molecular astrophysics.

Hunting for the “Missing Protoplanets”: Insights from Molecular Physics

Charles Law

NHFP Sagan Fellow

University of Virginia

Website

Although exoplanet demographics show that planets form efficiently, unambiguous signatures of protoplanets within disks remain elusive, despite a growing body of compelling, yet circumstantial, evidence of their presence. In this talk, I will present a new approach that uses molecular physics to probe the depth of gas gaps in disks, estimate otherwise uncertain planet masses, and guide targeted multi-wavelength follow-up observations. I will focus on the benchmark system HD 163296, whose disk shows multiple features consistent with the presence of Jupiter-mass protoplanets. This work also yielded unexpected insights, including evidence for non-interstellar isotopic ratios that trace the unique formation history of this system. Finally, I will place these results in the context of next-generation facilities that will open the door to efficient searches for the “missing” population of embedded protoplanets.

NuSTAR Insights into Solar Active Region Heating

Jessie Duncan

Research Astrophysicist

NASA Marshall Space Flight Center

A major outstanding question in solar physics concerns the heating of the solar corona: what maintains its high temperature (>million Kelvin) vs. the cooler underlying layers of the solar atmosphere? Energetically, the origin of this heating must be the Sun’s magnetic field, but the processes by which it occurs remain undetermined. Solar flares involve plasma heating through magnetic energy release, but are not observed to occur frequently enough to maintain the corona’s temperature. Different potential heating mechanisms have different implications when it comes to the thermal distribution of coronal plasma at non-flaring times. Hard x-ray (HXR) instruments can provide unique sensitivity to emission from the very hottest material (>10 MK), a particularly valuable diagnostic. Study of coronal heating has historically been limited by the lack of a solar-dedicated space mission in this waveband with sufficient sensitivity to observe at non-flaring times. NuSTAR is a highly sensitive direct-focusing HXR observatory optimized to observe astrophysical sources. Through its rare solar observing campaigns, NuSTAR provides the most extensive existing dataset of HXR observations of quiescent solar active regions. This seminar will discuss results from an upcoming bulk study of these regions, implications for coronal heating, and what further work is needed.

X-ray Observation of Small-Scale Energy Release in the Solar Corona

Jessie Duncan

Research Astrophysicist

NASA Marshall Space Flight Center

The solar corona is a dynamic, magnetically-dominated environment. Energy is continually released and transferred to other forms in impulsive events like solar flares. Observing the Sun in hard x-rays (HXRs) provides a particularly valuable diagnostic of energy release, as emission in this range is generated by both ultra-hot plasma and supra-thermal accelerated particles. Various HXR observatories have enabled study of coronal energy release at different scales (more than 8 orders of magnitude in event brightness). Sensitive, direct focusing HXR telescopes have more recently enabled examination of very faint events, as well as insight into energy transfer (coronal heating) at times with no distinguishable transient. This includes solar observations with NuSTAR, a highly sensitive astrophysics observatory. We discuss the structure of the corona and the nature of its energy release, with a focus on recent insights from NuSTAR and similar instruments.

Helioseismology as a Diagnostic of Solar Activity: From Interior Flows to Sunquakes

Ruizhu Chen

Research Scientist

Stanford University

Stanford COFFIES (Consequences Of Fields and Flows in the Interior and Exterior of the Sun) webpage

Helioseismology uses solar acoustic waves to probe regions beneath the visible surface. These measurements reveal large-scale interior flows, enable imaging of the far side of the Sun, and provide diagnostics of subsurface structures in magnetized active regions. This talk focuses on using helioseismology to understand sunquakes, which are acoustic waves excited by solar flares. A longstanding puzzle is why only a fraction of strong flares generate detectable sunquakes. To understand this selective sunquake occurrence, I will present a statistical study of major flares in Solar Cycle 24. By reconstructing the oscillatory velocity field at flare sites using helioseismic holography, we find that sunquakes are more likely to occur when the flare impulse coincides with a downward phase of the photospheric background oscillation. This suggests that the pre-existing photospheric velocity field plays a selective role in enabling seismic excitation. I also briefly discuss related observations of wave–magnetic interactions in sunspots, including a detected magnetic response to sunquake waves and the tracing of photospheric p-mode waves channeling upward into higher atmospheric layers. These results demonstrate how helioseismology provides insight into the coupling between interior waves, magnetic fields, and flare dynamics.

Mapping the Unseen Sun: Interior Flows and Far-Side Activity

Ruizhu Chen

Research Scientist

Stanford University

Stanford COFFIES (Consequences Of Fields and Flows in the Interior and Exterior of the Sun) webpage

Helioseismology has significantly transformed our understanding of the solar interior by probing hidden regions beneath the visible surface using acoustic oscillations. It revealed the Sun’s differential rotation and provided constraints on large-scale flow patterns that shape the solar magnetic cycle. Among these flows, the meridional circulation plays a central role in transporting magnetic flux and regulating the evolution of the solar cycle. However, the structure and depth dependence of the meridional circulation remain unsettled. I will explain how helioseismic techniques are used to measure meridional circulation, why it is particularly difficult to measure, and what current observations reveal. I will then show how our recent improved analysis methods refine our understanding of its depth-dependent structure and large-scale interior dynamics. I will also present how we can image solar activity on the far side of the Sun (the hemisphere not visible from Earth) using helioseismology, including recent approaches that incorporate machine learning. By detecting active regions before they rotate into Earth view, such far-side imaging extends our ability to monitor and predict solar activity.

Understanding the origin of giant planets

Yayaati Chachan

Postdoctoral Researcher

UC Santa Cruz

Website

Giant planets are the largest remnants of protoplanetary disks and exert significant influence on the formation and evolution of other planets within the same system. Understanding how they form is essential for advancing planet formation theory and for placing the solar system in context of the exoplanet population.

In this talk, I will summarize my multi-pronged efforts to investigate how giant planets such as Jupiter form around stars. I combine observational constraints with theoretical models of giant planet atmospheres, interiors, and orbital architectures to illuminate the process of their formation. The upcoming observational landscape for population-level characterization of giant planets is promising, and I will discuss how it can be leveraged to improve our understanding of planet formation.

Establishing links between planet composition and formation

Yayaati Chachan

Postdoctoral Researcher

UC Santa Cruz

Website

Connecting planet composition to formation has been a long-standing goal of the exoplanet community. In this talk, I will discuss a new framework that I developed which has made important strides toward establishing this connection. The first half of the talk is designed as a lecture to build intuition for the problem and to explain the proposed framework. In the second half, I demonstrate the power of the method by i) applying it to cutting-edge observations of the HR 8799 planets, ii) formulating a new minimum mass nebula estimate, and iii) shedding light on the high metallicities of super-Jupiters.

Coronal Mass Ejection Evolution in Structured Solar Wind

Nishtha Sachdeva

Assistant Research Scientist

University of Michigan

Coronal mass ejections (CMEs) are large-scale eruptions of plasma and magnetic field whose evolution is governed by both the initial magnetic configuration and the structured solar wind through which they propagate. Understanding CME behavior from the low corona to Earth requires addressing two central questions: How does the ambient solar wind shape global CME evolution? And how does the magnetic field configuration in the corona determine eruption onset and dynamics?

In this seminar, I will discuss the initiation and propagation of CMEs using data-driven global magnetohydrodynamic modeling. Variations in observed photospheric magnetic field maps modify the background solar wind and influence CME trajectory, propagation speed, and magnetic structure during Sun-to-Earth evolution. In the low corona, magnetic energy build-up and release govern eruption onset and early evolution. Observation-driven, physics-based models are used to characterize how the solar wind environment impacts CME evolution and to investigate the magnetic energy release that drives solar eruptions in complex magnetic configurations, illustrated through observed CME events.

Magnetic Explosions on the Sun: From Observation to Prediction

Nishtha Sachdeva

Assistant Research Scientist

University of Michigan

The Sun routinely releases large-scale eruptions of plasma and magnetic field into the heliosphere. These coronal mass ejections (CMEs) are primary drivers of space weather, yet predicting their evolution and impact remains a major challenge.

Over the past several decades, space-based observations have revealed how CMEs form and expand outward from the Sun as they travel through a highly structured and dynamic solar wind. Variations in magnetic topology and ambient plasma conditions can significantly influence CME propagation and their magnetic structure, ultimately shaping their impact at Earth.

In this colloquium, I will discuss how advances in multi-spacecraft observations and physics-based global modeling are improving our understanding of CME evolution. These models allow us to study the coupled CME-solar wind system and examine how the background solar wind influences CME propagation. I will highlight how uncertainties in magnetic field measurements and model parameters propagate into predictive uncertainty, and why quantifying these uncertainties is essential for improving our ability to forecast CMEs and deepen our understanding of these phenomena.

Comparative Exoplanet Magnetospheric Physics with Brown Dwarfs

Melodie Kao

Assistant Astronomer

Lowell Observatory

Website

Magnetic fields are central to the story of exoplanet evolution: they form in the deep interiors of planets, interface between a planet and its stellar wind environment, influence the thermal structures of planet atmospheres, and can even tell us about the presence of orbiting satellites. The broad relevance of magnetic fields offers a powerful possibility: using magnetospheric emissions as a new window to peer into exoplanet systems. In this talk, we will explore how brown dwarf auroral emissions can probe the complex physics occurring throughout exoplanet systems: from planet interiors and atmospheres, to stellar winds and satellite properties.

Deciphering Exoplanets: From JWST Breakthroughs to a Global Census

Sagnick Mukherjee

51 Pegasi b Postdoctoral Fellow

Arizona State University

Website

Exoplanets are astonishingly diverse, from hot Jupiters to temperate sub-Neptunes, placing our own Solar System in the larger context of the universe. This broad population, together with technological advancements and new facilities like JWST, provides us with the opportunity to understand how planets form, how they evolve, and what makes them habitable.

In this talk, I will show how we are uncovering the most important, yet least understood, physical processes that shape exoplanets and brown dwarfs. We do this by developing state-of-the-art theoretical models and leveraging ultra-precise observations. I will share highlights from my research and how I was able to constrain the strength of atmospheric dynamics for the first time in these substellar objects, a property previously uncertain by up to 8 orders of magnitude. I will also present evidence that the dividing lines between planets, brown dwarfs, and stars are not as easily defined as previously thought. Instead, the boundaries between these objects are more subtle and are strongly shaped by their companion stars. Then, I will highlight our discovery of the first direct evidence for a cloud cycle in a distant world, an analog of Earth’s water cycle. I will close with a forward-looking roadmap built on three pillars: an atmospheric census of diverse exoplanets, next-generation physics-driven models to turn surveys into quantitative constraints, and a path toward characterizing Earth 2.0.

Exoplanet Atmospheres in 3D: A New Lens on Physics and Chemistry

Sagnick Mukherjee

51 Pegasi b Postdoctoral Fellow

Arizona State University

Website

Many transiting exoplanets seem to have aerosols in their atmospheres, but it is still unclear what those aerosols really are. They could be clouds that form when gases cool and condense, or they could be hazes created by stellar UV-driven chemistry.

In this talk, I focus on a simple idea: instead of treating a planet’s atmosphere as a homogeneous and stationary object, we can look at different parts of its limbs as it passes in front of its star. Using JWST observations of WASP-94A b, I will show that a planet can look very different from one side to the other; one side appearing much cloudier, while the other side is clearer and lets us measure water absorption features more easily. These tantalizing results suggest that clouds may be actively forming, moving around the planet, and clearing away, rather than being a static global blanket. I will discuss why this matters for what we think we are measuring, especially when we use spectra to infer atmospheric composition to answer some of the biggest questions in astronomy. I will also place this result in a broader context, with hints that similar “two-sided” atmospheres may be common among hot Jupiters, and argue that making progress in understanding diverse exoplanets, from hot Jupiters down to sub-Neptunes and ultimately Earth-like worlds, will require observations and models that treat exoplanet atmospheres as dynamic, 3D worlds.

Bridging the Corona and Heliosphere with Contemporary Solar Missions

Yeimy Rivera

Astrophysicist

Center for Astrophysics | Harvard & Smithsonian

CfA Faculty Page

Addressing the fundamental mysteries of solar wind acceleration and heating requires a unified approach that bridges the traditional divide between remote-sensing and in situ observations. The heating of the solar wind begins in the low corona, but the mechanisms by which magnetohydrodynamic (MHD) waves transport and eventually dissipate their energy to heat the plasma remains a subject of ongoing discussion.

In this seminar, I will discuss how our field can address these topics by leveraging multi-messenger solar missions to close these scientific gaps. Specifically, I will discuss how the Daniel K. Inouye Solar Telescope (DKIST) provides unprecedented high-resolution diagnostics of waves in the corona while the Parker Solar Probe and PUNCH missions directly sample and image, respectively, the resulting turbulent evolution and dynamics out to the edge of the sub-Alfvénic corona and beyond. To effectively test current theoretical frameworks, I focus on two primary objectives: 1) developing advanced connection science techniques to rigorously link coronal magnetic footpoints to inner-heliospheric particle/field observations, and 2) deriving observational constraints, such as non-thermal line broadening, power spectral densities, and other quantities, to parameterize energy partitioning. By robustly establishing these direct links, we can provide a more complete, self-consistent picture of how energy flows from the solar atmosphere into the inner heliosphere, capitalizing on the unprecedented combination of remote and in situ observatories currently studying the Sun.

Quantifying the role of Alfvén Waves in the Heating and Acceleration of the Solar Wind

Yeimy Rivera

Astrophysicist

Center for Astrophysics | Harvard & Smithsonian

CfA Faculty Page

The solar wind is a continuous stream of charged particles that flows out from the Sun’s upper atmosphere, the corona, throughout interplanetary space defining the heliosphere. While the solar wind has been studied for decades, the specific physical mechanisms that heat and accelerate the plasma beyond free expansion are not fully understood. Recent studies from the Parker Solar Probe confirms that Alfvén waves that permeate the solar wind near the Sun are the necessary additional energy source to explain the highest speed wind observed near the Earth. However, few studies probe the main heating and acceleration phase, which occurs below the Alfvén surface, the region where Alfvén wave speeds exceed the bulk outward particle flow.

I present our recent work achieving a rare, comprehensive tracking of a single solar wind stream through the critical evolutionary points of its expansion, between its subsonic and super-Alfvénic state. This study leverages a unique observational window during the 2024 Total Solar Eclipse, which facilitated a synchronized, multi-perspective campaign across ground- and space-based telescopes, including the Daniel K. Inouye Solar Telescope (DKIST). By integrating near-contemporaneous, multi-wavelength datasets, we characterize the plasma and magnetic environment of a nascent solar wind stream emerging from an equatorial coronal hole. We trace the energy budget of a single solar wind stream from the corona to the heliosphere, demonstrating that enthalpy and Alfvén wave energy fluxes dominate the low-coronal budget. Our results indicate that the majority of this energy is converted into ion heating and acceleration within the Alfvén surface. Furthermore, we show that the evolution of Alfvénic fluctuations deviates from a dissipationless expansion, pointing to significant, persistent dissipation and heating beginning in the low corona. I conclude by discussing how heavy ion measurements can further serve as a marker for the specific plasma processes at play, offering insight to how magnetic energy is transformed into heat in the solar wind.

One-minute colloquium

Presented by the IfA Community

Participants will have one (1) slide and one (1) minute to present their research.

For newcomers, this is a great introduction to what goes on at IfA; for others who might’ve been stuck under the ice of Enceladus for the past year, it’s always interesting to see what your peers have been up to recently.

Planetary Demographics and Dynamics: Disentangling the Processes Shaping Exoplanetary Systems

Yubo Su

Postdoctoral Research Fellow

Canadian Institute for Theoretical Astrophysics

Website

With over six thousand known exoplanets known today, and many systems having exquisitely detailed characterizations obtained using a wide range of impressively precise techniques, the data available for studying planetary system formation and evolution are almost embarrassingly abundant. In particular, many notable demographic trends have emerged that suggest strong observational constraints not just at a system-by-system level but across entire populations of exoplanets. Nevertheless, the inverse problem of identifying these observations with specific theories continues to be challenging even in the most well-studied populations. In this talk, I will discuss some of the theoretical difficulties at the heart of this ongoing effort, most of which originate from the fact that the architectures of the planetary systems we observe today are sculpted by a long list of processes spanning a range of both spatial and temporal scales. I will focus on the effort towards interpreting the orbital orientations of hot Jupiters.

SCALES: A New AO Imager and IFS for Keck Observatory

Andy Skemer

Professor

UC Santa Cruz

Website

SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy) is a new infrared adaptive optics imager and integral field spectrograph (IFS) for the W. M. Keck Observatory — Keck’s first instrument purpose-built for exoplanet direct imaging. Operating at 1-5 μm, SCALES offers capabilities complementary to JWST, including higher contrast at small inner working angles, higher spectral resolution, and flexible cadence for Solar System monitoring. The IFS employs a dual-mode design featuring both a conventional lenslet array for low-resolution and a novel lenslet-plus-slicer for medium-resolution. I will present the current instrument status: all optics meet specification, lab data from both the imager and low-resolution IFS are in hand, and the slicer is installed and being aligned. I will also highlight SCALES’ key science programs, including accreting protoplanets embedded in disks, GAIA-identified companions, and a twilight observing mode targeting the outer Solar System.

Semiconductor sensor and readout R&D for particle (astro)physics

Jennifer Ott

Assistant Professor

UH Mānoa Department of Electrical & Computer Engineering

UHM faculty website

Particle physics experiments pose challenging requirements on semiconductor detectors: fine segmentation and precise timing resolution are required simultaneously with low power consumption, low mass and high radiation tolerance. Here I will present ongoing developments and future directions in semiconductor sensor research and development for high-energy and nuclear physics. I will focus especially on the application of precision timing with silicon sensors. The PIONEER experiment at Paul Scherrer Institute will utilize low-gain avalanche diodes (LGADs) for the study of charged pion decays, leading towards particle tracking in 5 dimensions. On the other hand, time-of-flight detectors can provide particle ID at low momenta, which is crucial for the first detector to be built at the Electron-Ion Collider, and is also being spearheaded by UH as an upgrade to the Belle-II experiment in Japan.

I will also present the status and near-future plans for the for the ADAPT Prototype of the Advanced Particle-astrophysics Telescope (APT), and ongoing work on waveform sampling ASICs at UH.

Bio: Dr. Jennifer Ott is an assistant professor at the University of Hawaiʻi at Mānoa in the Department of Electrical & Computer Engineering, specializing in ultrafast semiconductor sensors and readout electronics.

Dr. Ott received her B.Sc. in 2014 and M.Sc. in 2015 in radiochemistry from the University of Helsinki, Finland, taking first steps into research on radioactive tracers and radiation detection technology. She continued to pursue a doctoral degree in Advanced Materials and Photonics under joint supervision by Helsinki Institute of Physics and Aalto University School of Electrical Engineering, focusing on the fabrication of silicon pixel sensors that utilize thin films grown by atomic layer deposition as resistive and dielectric layers. In 2021 Dr. Ott moved to the University of California, Santa Cruz as a postdoctoral fellow to study precision tracking and timing sensors, as well as novel readout electronics, for high-energy and nuclear physics experiments. This included the electrical testing of pixel modules for the upgrade of the ATLAS experiment, and research towards the future ePIC and PIONEER experiments. Dr. Ott joined the Department of Electrical and Computer Engineering at the University of Hawaiʻi as assistant professor in January 2025, along with a cooperating graduate faculty appointment in the Department of Physics & Astronomy, continuing and expanding on her instrumentation expertise to advance the integration of Machine Learning and Artificial Intelligence into front-end electronics.

Geosciences in Astronomy: From Magma Oceans to Liquid-Water Worlds

Renyu Hu

Associate Professor of Astronomy and Astrophysics

Penn State University

Website

The James Webb Space Telescope (JWST) is opening a new era in exploring the atmospheres and surfaces of small exoplanets, bringing geosciences to the forefront of astronomy. I will highlight recent discoveries that reveal the intimate links between geology and atmospheric evolution. I will also discuss efforts to identify liquid-water conditions on temperate sub-Neptunes using our next-generation EPACRIS model, and outline how these advances are paving the way toward characterizing true Earth analogs.

Are we looking for exomoons in the wrong places?

Andrew Vanderburg

Assistant Professor of Astronomy

Center for Astrophysics | Harvard & Smithsonian

Website

Moons are ubiquitous in our solar system, outnumbering the major planets in our system by more than 20:1. However, despite the discovery of over 6000 exoplanets, we are still waiting for the first confirmed discovery of a moon beyond the solar system. Is this because we are looking for moons in the wrong places? Our most successful exoplanet detection techniques are biased towards finding planets close to their host stars, even though most of the moons in our solar system are found orbiting the outer planets. I will discuss several different ways we might look for exomoons around more distant planets and I will pitch a survey that might deliver the first population of exomoons in the next few years.

From stars to Mars and back again: My odyssey back to the IfA

James Wray

Professor

Georgia Institute of Technology

Website

I got my start in planetary research at IfA’s REU program, searching for debris disks around low-mass stars. Then graduate school provided an opportunity to use the most powerful telescope ever sent to another planet: Mars. I will discuss how remote sensing punctuated by landings on the red planet’s surface has advanced our understanding of its habitability over the past two decades. Comparable missions to exoplanets are not yet feasible, but recently discovered interstellar objects deliver exoplanetary material to our neighborhood. I will describe ongoing studies of 3I/ATLAS–including from spacecraft at Mars!–and how objects like it could inspire the next breakthroughs in understanding planet formation.

A Golden Age of Asteroseismology with Kepler and TESS

Tim Bedding

Professor & ARC Laureate Fellow

University of Sydney

University of Sydney faculty website

Asteroseismology uses the natural oscillation modes of stars to study their interiors. The wonderfully precise measurements by NASA’s Kepler and TESS missions are ideal data sources for the technique. These space telescopes have been monitoring the brightness of hundreds of thousands of stars, with the main goal of discovering extra-solar planets as they transit their parent stars. At the same time, observations of stellar oscillations have led to a revolution in asteroseismology. I will discuss some of the key results, including the use of gravity modes to probe the cores of red giant stars, the characterization of stars found to host exoplanets, and the measurement of ages for young stellar associations.