PTYS/LPL Faculty

Daniel Apai


  • Davin Flateau (PTYS)
  • Benjamin Rackham (Astronomy)


  • Hao Yang
  • Theodora Karalidi


  • Esther Buenzli


  • Justin Rogers, 2008-2012, Johns Hopkins University
  • Laszlo Szucs, 2009-2011, Space Telescope Science Institute and The University of Szeged
  • Veselin Kostov, 2009, Johns Hopkins University
  • Judit Szulagyi, 2010-2011, Space Telescope Science Institute and Eotvos Lorand University
  • Emily Hardegree-Ullman, 2006-2007, The University of Arizona
  • Yancey Sechrest, 2005-2006, The University of Arizona
  • Emily E. Berkson (UA Astronomy)
  • William Nolan (UA CAMPARE)
Daniel Apai
Assistant Professor
Astrobiology, Exoplanetary systems, Planet formation
Ph.D., 2004, University of Heidelberg

Steward   #338

Years with LPL:  2011 to present


Dr. Apai’s research focuses on the formation and properties of exoplanetary systems, through direct observations of protoplanetary and debris disks and giant exoplanets. He is particularly interested in the formation of habitable planets and the characterization of exoplanetary atmospheres, including the search for biomarkers.

Dr. Apai’s group studies exoplanets via high-contrast imaging and by observing exoplanetary transits and eclipses. High-contrast imaging allows the exploration of the exoplanet population in the outer planetary systems, leading to the discovery and characterization of giant planets and constraints on their frequency. Planetary eclipses, on the other hand, enable the study of heavily irradiated exoplanets with atmospheres as hot as red dwarf stars.

Studies of planetary atmospheres provide only limited information on the bulk composition and geophysics of planets: detailed understanding of the physics of exoplanets also requires an understanding of their formation. Dr. Apai has worked on establishing a consistent framework for planet formation in the Solar System and around other stars by reconciling the meteoritic and Solar System evidence with astronomical observations. He also carried out detailed studies that demonstrated that the initial and boundary conditions of planet formation are stellar mass-dependent, arguing for different disk evolution around the much more common low-mass stars.

Read Dr. Apai's blog on exoplanet exploration and astrobiology here.

More about Dr. Apai

CV for Dr. Apai (PDF)


  • Extrasolar Storms - The Physics and Chemistry of Evolving Cloud Structures in Brown Dwarf Atmospheres: Spitzer Exploration Science Program (PI Apai)
  • Patchy Clouds and Rotation Periods in Exoplanets: Space Telescope Science Institute (PI Apai)
  • Imaging Disk-Planet Interactions in the Beta Pictoris Disk: Hubble space Telescope Cycle-19 Data Analysis Program (PI Apai)


NASA ADS Author search: Daniel Apai


Todorov, K. O., et al. A Search for Companions to Brown Dwarfs in the Taurus and Chamaeleon Star-Forming Regions 2014ApJ...788...40T

Buenzli, E., et al. Brown Dwarf Photospheres are Patchy: A Hubble Space Telescope Near-infrared Spectroscopic Survey FindsFrequent Low-level Variability 2014ApJ...782...77B

Close, L. M., et al. Discovery of Hα Emission from the Close Companion inside the Gap of Transitional Disk HD 142527 2014ApJ...781L..30C

Gucsik, A., et al. Cathodoluminescence microscopy and spectroscopy of forsterite from Kaba meteorite: An application to the study of hydrothermal alteration of parent body 2013M&PS...48.2577G

Moór, A., et al. ALMA Continuum Observations of a 30 Myr Old Gaseous Debris Disk around HD 21997 2013ApJ...777L..25M

Kóspál, Á.et al. ALMA Observations of the Molecular Gas in the Debris Disk of the 30 Myr Old Star HD 21997 2013ApJ...776...77K

Moór, A., et al. A Resolved Debris Disk around the Candidate Planet-hosting Star HD 95086 2013ApJ...775L..51M

Mohanty, S., et al. Protoplanetary Disk Masses from Stars to Brown Dwarfs 2013ApJ...773..168M

Bonnefoy, M., et al. The near-infrared spectral energy distribution of β Pictoris b 2013A&A...555A.107B

Apai, D., et al. HST Spectral Mapping of L/T Transition Brown Dwarfs Reveals Cloud Thickness Variations 2013ApJ...768..121A

Heinze, A. N., et al. Weather on Other Worlds. I. Detection of Periodic Variability in the L3 Dwarf DENIS-P J1058.7-1548 with Precise Multi-wavelength Photometry 2013ApJ...767..173H

Rogers, J., López-Morales, M., Apai, D., Adams, E. Benchmark Tests for Markov Chain Monte Carlo Fitting of Exoplanet Eclipse Observations 2013ApJ...767...64R

Apai, D. Protoplanetary disks and planet formation around brown dwarfs and very low-mass stars 2013AN....334...57A

Metchev, S., et al. Clouds in brown dwarfs and giant planets 2013AN....334...40M

Kostov, V., Apai, D. Mapping Directly Imaged Giant Exoplanets 2013ApJ...762...47K

Buenzli, E., et al. Vertical Atmospheric Structure in a Variable Brown Dwarf: Pressure-dependent Phase Shifts in Simultaneous Hubble Space Telescope-Spitzer Light Curves 2012ApJ...760L..31B

Szulágyi, J., et al. Observational Constraints on the Stellar Radiation Field Impinging on Transitional Disk Atmospheres 2012ApJ...759...47S

Robberto, M., et al. An HST Imaging Survey of Low-mass Stars in the Chamaeleon I Star-forming Region 2012AJ....144...83R

Skemer, A. J., et al. First Light LBT AO Images of HR 8799 bcde at 1.6 and 3.3 μm: New Discrepancies between Young Planets and Old Brown Dwarfs 2012ApJ...753...14S

Rodigas, T. J., et al. The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging 2012ApJ...752...57R

Chauvin, G., et al. Orbital characterization of the β Pictoris b giant planet 2012A&A...542A..41C

Lagrange, A.-M., et al. The position of β Pictoris b position relative to the debris disk 2012A&A...542A..40L

Robberto, Spina, Da Rio, Apai et al. 2012 Astronomical Journal, An HST Imaging Survey of Low-mass Stars in the Chamaeleon I star-forming region. In press.

Quanz, S. P., et al. Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging 2012A&A...538A..92Q

Moór, A., et al. Molecular Gas in Young Debris Disks 2011ApJ...740L...7M

Kun, M., et al. Inner disc rearrangement revealed by dramatic brightness variations in the young star PV Cep 2011MNRAS.413.2689K

Teske, J. K., et al. Measuring Organic Molecular Emission in Disks with Low-resolution Spitzer Spectroscopy 2011ApJ...734...27T

Kun, M., et al. A Peculiar Young Eruptive Star in the Dark Cloud Lynds 1340 2011ApJ...733L...8K

Skemer, A. J., et al. Evidence Against an Edge-on Disk Around the Extrasolar Planet, 2MASS 1207 b and a New Thick-cloud Explanation for Its Underluminosity 2011ApJ...732..107S

Bonnefoy, M., et al. High angular resolution detection of β Pictoris b at 2.18 μm 2011A&A...528L..15B

Moór, A., et al. Structure and Evolution of Debris Disks Around F-type Stars. I. Observations, Database, and Basic Evolutionary Aspects 2011ApJS..193....4M

Currie, T., et al. A Combined Subaru/VLT/MMT 1-5 μm Study of Planets Orbiting HR 8799: Implications for Atmospheric Properties, Masses, and Formation 2011ApJ...729..128C

Rogers, J. C., et al. ERRATUM: "Ks-band Detection of Thermal Emission and Color Constraints to CoRoT-1b: A Low-albedo Planet with Inefficient Atmospheric Energy Redistribution and a Temperature Inversion" 2010ApJ...723.1825R

Quanz, S. P., et al. First Results from Very Large Telescope NACO Apodizing Phase Plate: 4 μm Images of The Exoplanet β Pictoris b 2010ApJ...722L..49Q

Apai, D., Pascucci, I. A Possible Nitrogen Barrier to Life Around Cool Stars 2010M&PSA..73.5362A

Szücs, L., et al. Stellar-mass-dependent Disk Structure in Coeval Planet-forming Disks 2010ApJ...720.1668S

Lagrange, A.-M., et al. A Giant Planet Imaged in the Disk of the Young Star β Pictoris 2010Sci...329...57L

Apai, D., et al. Lessons from a High-Impact Observatory: The Hubble Space Telescope's Science Productivity between 1998 and 2008 2010PASP..122..808A

López-Morales, M., et al. Day-side z'-band Emission and Eccentricity of WASP-12b 2010ApJ...716L..36L

Apai, D., Connolly, H. C., Jr., Lauretta, D. S. Thermal Processing in Protoplanetary Nebulae

Apai, D., Lauretta, D. S. Planet Formation and Protoplanetary Dust

Apai, D. A., Lauretta, D. S. Protoplanetary Dust: Astrophysical and Cosmochemical Perspectives

Rogers, J. C., et al. Ks-Band Detection of Thermal Emission and Color Constraints to CoRoT-1b: A Low-Albedo Planet with Inefficient Atmospheric Energy Redistribution and a Temperature Inversion 2009ApJ...707.1707R

Lagrange, A.-M., et al. Constraining the orbit of the possible companion to β Pictoris. New deep imaging observations 2009A&A...506..927L

Janson, M., et al. Imaging search for the unseen companion to ε Ind A - improving the detection limits with 4 μm observations 2009MNRAS.399..377J

Apai, D., Pascucci, I. Protoplanetary Disks Around Cool Stars: Differences in the Disk Structure, Dust Processing and Organic Chemistry 2009M&PSA..72.5361A

Apai, D. Origins of Planetary Systems: Constraints and Challenges 2009EM&P..105..311A

Moór, A., et al. The Discovery of New Warm Debris Disks Around F-type Stars 2009ApJ...700L..25M

Grady, C. A., et al. Revealing the Structure of a Pre-Transitional Disk: The Case of the Herbig F Star SAO 206462 (HD 135344B) 2009ApJ...699.1822G

Gáspár, A., et al. The Low Level of Debris Disk Activity at the Time of the Late Heavy Bombardment: A Spitzer Study of Praesepe 2009ApJ...697.1578G

Pascucci, I., et al. The Different Evolution of Gas and Dust in Disks around Sun-Like and Cool Stars 2009ApJ...696..143P

Juhász, A., et al. Do We Really Know the Dust? Systematics and Uncertainties of the Mid-Infrared Spectral Analysis Methods 2009ApJ...695.1024J

Meeus, G., et al. MBM 12: young protoplanetary discs at high galactic Latitude 2009A&A...497..379M

Dullemond, C., et al. Structure and evolution of protoplanetary disks 2008JPhCS.131a2018D

Kóspál, Á., et al. High-resolution polarimetry of Parsamian 21: revealing the structure of an edge-on FUOri disc 2008MNRAS.383.1015K

Pascucci, I., et al. Medium-Separation Binaries Do Not Affect the First Steps of Planet Formation 2008ApJ...673..477P

Apai, D., et al. A Survey for Massive Giant Planets in Debris Disks with Evacuated Inner Cavities 2008ApJ...672.1196A

Kasper, M., et al. A novel L-band imaging search for giant planets in the Tucana and β Pictoris moving groups 2007A&A...472..321K

Pascucci, I., Apai, D. Stellar Companions and the Early Stages of Planet Formation 2007M&PSA..42.5248P

Apai, D., Pascucci, I. Dust Settling and Dust Processing in Protoplanetary Disks Around Cool Stars 2007M&PSA..42.5180A

Quanz, S. P., Apai, D., Henning, T. Dust Rings and Filaments around the Isolated Young Star V1331 Cygni 2007ApJ...656..287Q

Apai, D., et al. Massive Binaries in High-Mass Star-forming Regions: A Multiepoch Radial Velocity Survey of Embedded O Stars 2007ApJ...655..484A

Moór, A., et al. Nearby Debris Disk Systems with High Fractional Luminosity Reconsidered 2006ApJ...644..525M

Puga, E., et al. Outflows, Disks, and Stellar Content in a Region of High-Mass Star Formation: G5.89-0.39 with Adaptive Optics 2006ApJ...641..373P

Dullemond, C. P., Apai, D., Walch, S. Crystalline Silicates as a Probe of Disk Formation History 2006ApJ...640L..67D

Apai, D., et al. The Onset of Planet Formation in Brown Dwarf Disks 2005Sci...310..834A

Apai, D., et al. Infrared portrait of the nearby massive star-forming region IRAS 09002-4732 2005A&A...434..987A

Apai, D., et al. HST/NICMOS observations of a proto-brown dwarf candidate 2005A&A...433L..33A

Wang, H., et al. Optical Outflows in the R Coronae Australis Molecular Cloud 2004ApJ...617.1191W

Sterzik, M. F., et al. Evolution of young brown dwarf disks in the mid-infrared 2004A&A...427..245S

Apai, D., et al. Grain growth and dust settling in a brown dwarf disk. Gemini/T-ReCS observations of CFHT-BD-Tau 4 2004A&A...426L..53A

Pascucci, I., et al. The hot core-ultracompact H II connection in G10.47+0.03 2004A&A...426..523P

Grady, C. A., et al. The Environment of the Optically Brightest Herbig Ae Star, HD 104237 2004ApJ...608..809G

Apai, D. Ph.D. Exploring the environment of young stars: disks, companions and clusters 2004PhDT.........1A

Apai, D., et al. NACO polarimetric differential imaging of TW Hya. A sharp look at the closest T Tauri disk 2004A&A...415..671A

Wang, H., et al. FU Orionis: A Binary Star? 2004ApJ...601L..83W

Kun, M., et al. Initial Conditions of Low, Intermediate and High Mass Star Formation 2004BaltA..13..434K

Klein, R., et al. First Detection of Millimeter Dust Emission from Brown Dwarf Disks 2003ApJ...593L..57K

Pascucci, I., et al. The First Detailed Look at a Brown Dwarf Disk 2003ApJ...590L.111P

Apai, D., et al. Probing Dust around Brown Dwarfs: The Naked LP 944-20 and the Disk of Chamaeleon Hα 2 2002ApJ...573L.115A