mountain profile Institute for Astronomy University of Hawaii


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One of the most exciting topics in modern astronomy is the discovery and characterization of exoplanets -- planets in orbit around stars other than our Sun. IfA astronomers pursue studies of gas-giant, ice-giant, and rocky planets using the latest ground-based and space-based observatories.


Planet Formation

Jonathan Williams studies the formation of planets through observations and modeling of protoplanetary disks. Building on a legacy of work with the Submillimeter Array, we use the Atacama Large Millimeter Array (ALMA) to study disk populations in nearby regions with different ages. This allows us to study how disks evolve around stars of different masses. We find that disks are initially massive but appear to rapidly lose mass within a few Myr. This is likely due to the growth of dust grains from millimeters to pebble-sized building blocks of planets. The gas content also evolves, but whether this is due to chemistry or physical loss, is a subject of current research with profound implications for understanding exoplanet composition.

ALMA has shown that protoplantary disks are highly structured, with rings, cavities and spirals commonplace. A likely reason for these features are protoplanets themselves. With high contrast infrared imaging, we are searching for planets within disks. Ultimately, we hope to make direct links between disk properties and the planets that they form. This is the key to understanding the origins of our Solar System.


Infrared image of a giant planet and protoplanetary disk around the young, approximately solar mass star, PDS70. The star is at the center and is masked out in this image for clarity. The bright point source is the planet, with a mass estimated from its luminosity of several Jupiters. The ring of emission is scattered light from the dust particles from the disk. This image is from Muller et al. 2018 and is data taken with the ESO Very Large Telescope. We are currently analyzing ALMA observations of the dust and gas emission from the disk to study its properties and examine the planet-disk dynamical interaction.

Eric Gaidos (Department of Earth Sciences, IfA Cooperating Faculty) is interested in the formation and evolution of planets, especially Earth-like planets that are potentially habitable. In that context he seeks to better understand conditions on/in the early Earth and Solar System, and the implications for the origins of life. He is the PI of a Las Cumbres Observatory Key Project to study inner planet-forming disks around young stars, and the Hawaii PI of a NASA-funded Interdisciplinary Consortium for Astrobiology Research team. He is the recipient of several international awards: the Samuel Pufendorf Chair, a Fulbright Award, and an Ida Pfeiffer Professorship.


Exoplanet Characterization

Daniel Huber studies the fundamental properties of stars and stellar populations in our galaxy, including the discovery and characterization of exoplanets using the transit and radial velocity methods. He is the former co-chair of the Stellar Properties Working Group for the NASA Kepler Mission and holds leadership positions within the TESS Mission, including as a steering committee member of the TESS Asteroseismic Science Consortium (TASC) and member of the TESS Spectroscopic Steering Committee. His work has been supported by NASA, NSF and the Research Corporation for Science Advancement, and he is the recipient of a NASA Exceptional Scientific Achievement Medal, an Alfred P. Sloan Fellowship, and the University of Hawaii Regents' Medal for Excellence in Research. 

Michael Liu conducts direct studies of gas-giant exoplanets and brown dwarfs to discover such objects, characterize their properties, and probe their formation. He is especially well known for such work using wide-field sky surveys and adaptive optics on the largest ground-based telescopes. He has led/co-led 3 major international science campaigns, including the first large exoplanet imaging survey (the Gemini NICI Planet-Finding Campaign) and the ongoing Hawaii Infrared Parallax Program. He is co-PI for the upcoming Keck All-Sky Precision AO (KAPA) system and co-lead for its planned key science program on young exoplanets. Support for his work has come from NSF, NASA, and the Moore Foundation. He has been awarded a Hubble Fellowship, an Alfred P. Sloan Fellowship, and the University of Hawaii Regents' Medal for Excellence in Research.


Exoplanet Instrumentation

Christoph Baranec develops, builds, and uses cutting-edge adaptive-optics technology on ground-based telescopes. He pioneered the development of automated AO systems as PI of the Robo-AO system on the Palomar 60-inch telescope, which was used to help validate nearly all of the 4000 NASA Kepler candidate exoplanets by searching for stellar blends. He is leading development of the successor system, Robo-AO-2 on the UH888 telescope. He has received an Alfred P Sloan Fellowship and the University of Hawaii Regents' Medal for Excellence in Research. He is supported by grants from NASA, NSF, Mt. Cuba Astronomical Foundation, Office of Naval Research, the US Naval Observatory, and Keck Observatory.

Michael Bottom works on directly imaging planets around other stars. To do this, he builds and uses instrumentation including extreme adaptive optics systems, low-noise infrared detectors, and coronagraphs for both ground and space telescopes. Michael is the PI of grants from the Heising-Simons Foundation, NASA, NSF, and the Mt. Cuba Astronomical Foundation. He is the co-recipient of two NASA Group Achievement awards and three NASA Voyager awards for individual achievement. He was recently elected to serve on the Executive Committee for NASA's ExoPlanet Analysis Group.

Related Areas

Exoplanet studies inevitably connect with other active areas of IfA research, including Instrumentation, the Solar System, and Stars. Faculty with overlapping research interests include: