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.

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.

Plus, witness the ruthless truncation as the presentation auto-advances slides after exactly 60 seconds!

TBA

Yubo Su

Postdoctoral Research Fellow

Canadian Institute for Theoretical Astrophysics

Website

Coming soon.

TBA

Andy Skemer

Professor

UC Santa Cruz

Website

Coming soon.

TBA

Andrew Vanderburg

Assistant Professor of Astronomy

Center for Astrophysics | Harvard & Smithsonian

Website

Coming soon.

TBA

Renyu Hu

Associate Professor of Astronomy and Astrophysics

Penn State University

Website

Coming soon.