Current Grants

• Alien Earths and Earths in Other Solar Systems – A large interdisciplinary NASA Nexus for Exoplanet System Science project to study the formation and properties of habitable worlds and to identify which nearby planetary systems are more likely to host habitable worlds. AE/EOS is a 10-year, $12M interdisciplinary project that includes over 30 senior investigators, and about 40 graduate students and postdocs.
• Project EDEN – A search for habitable worlds within fifty lightyears.

Current Spacecraft Involvement

• Nautilus Space Observatory – The Nautilus Space Observatory concept and its supporting technology development effort is to enable large-scale searches for atmospheric biosignatures via a paradigm change in the way space telescopes are designed and built. Funded by the Gordon and Betty Moore Foundation, our team has developed a novel, ultralight space optical system that makes large-diameter, high-performance optical systems replicable at relatively low cost.
• Pandora Space Telescope – A funded NASA SmallSat/Pioneers program, Pandora will launch in 2025 and will study the atmospheres of small, transiting extrasolar planets in 20 nearby planetary systems. 

Former Students

• Quentin Jay Socia (UA/Astronomy)
• Jeremy Dietrich (UA/Astronomy)
• Alex Bixel (UA/Astronomy)
• Kevin Wagner (UA/Astronomy)
• Yifan Zhou (UA/Astronomy)
• Ben Wei Peng Lew (UA/Astronomy)
• Benjamin Rackham (UA/Astronomy)
• Davin Flateau, 2015 (M.Sc.)
• Jake Ryan Hanson, 2014, University of Arizona
• Judit Szulagyi, 2010-2011, Space Telescope Science Institute and Eotvos Lorand University
• Laszlo Szucs, 2009-2011, Space Telescope Science Institute and University of Szeged
• Veselin Kostov, 2009, Johns Hopkins University
• Justin Rogers, 2008-2012, Johns Hopkins University
• Emily Hardegree-Ullman, 2006-2007, University of Arizona
• Yancey Sechrest, 2005-2006, University of Arizona
• Emily E. Berkson (UA Astronomy)
• William Nolan (UA CAMPARE)

Current Postdocs

• Kevin Wagner
• Alex Bixel
• Megan Mansfield
• Kevin Hardegree-Ullman

Former Postdocs

• Alex Bixel
• Kevin Wagner
• Sebastiaan Krijt
• Benjamin Rackham
• Gijs Mulders
• Jonathan Rees
• Elena Manjavacas
• Michael McGauley
• Hao Yang
• Theodora Karalidi
• Esther Buenzli

Complete publications list available from: NASA ADS Author search: Daniel Apai

Recent refereed publications (NASA ADS): Years 2019 through June 2021

Kirk, James, Rackham, Benjamin V., MacDonald, Ryan J., López-Morales, Mercedes, Espinoza, Néstor, Lendl, Monika, Wilson, Jamie, Osip, David J., Wheatley, Peter J., Skillen, Ian, Apai, Dániel, Bixel, Alex, Gibson, Neale P., Jordán, Andrés, Lewis, Nikole K., Louden, Tom, McGruder, Chima D., Nikolov, Nikolay, Rodler, Florian, & Weaver, Ian C. 2021, The Astronomical Journal. ACCESS and LRG-BEASTS: A Precise New Optical Transmission Spectrum of the Ultrahot Jupiter WASP-103b

Lin, Chia-Lung, Chen, Wen-Ping, Ip, Wing-Huen, Apai, Dániel, Bixel, Alex, Boyle, Richard, Chavez, Jose Perez, Espinoza, Nestor, Gibbs, Aidan, Gabor, Paul, Henning, Thomas, Mancini, Luigi, Rackham, Benjamin V., Schlecker, Martin, Dietrich, Jeremy, Socia, Quentin Jay, Keppler, Miriam, Bhandare, Asmita, & Häberle, Maximilian 2021, The Astronomical Journal. EDEN: Flare Activity of the Nearby Exoplanet-hosting M Dwarf Wolf 359 Based on K2 and EDEN Light Curves

Biller, Beth A., Apai, Dániel, Bonnefoy, Mickaël, Desidera, Silvano, Gratton, Raffaele, Kasper, Markus, Kenworthy, Matthew, Lagrange, Anne-Marie, Lazzoni, Cecilia, Mesa, Dino, Vigan, Arthur, Wagner, Kevin, Vos, Johanna M., & Zurlo, Alice 2021, Monthly Notices of the Royal Astronomical Society. A high-contrast search for variability in HR 8799bc with VLT-SPHERE

Fang, Min, Kim, Jinyoung Serena, Pascucci, Ilaria, & Apai, Dániel 2021, The Astrophysical Journal. An Improved Hertzsprung-Russell Diagram for the Orion Trapezium Cluster

Wagner, K., Boehle, A., Pathak, P., Kasper, M., Arsenault, R., Jakob, G., Käufl, U., Leveratto, S., Maire, A. -L., Pantin, E., Siebenmorgen, R., Zins, G., Absil, O., Ageorges, N., Apai, D., Carlotti, A., Choquet, É., Delacroix, C., Dohlen, K., Duhoux, P., Forsberg, P., Fuenteseca, E., Gutruf, S., Guyon, O., Huby, E., Kampf, D., Karlsson, M., Kervella, P., Kirchbauer, J. -P., Klupar, P., Kolb, J., Mawet, D., N'Diaye, M., de Xivry, G. Orban, Quanz, S. P., Reutlinger, A., Ruane, G., Riquelme, M., Soenke, C., Sterzik, M., Vigan, A., & de Zeeuw, T. 2021, Nature Communications. Author Correction: Imaging low-mass planets within the habitable zone of α Centauri

Weaver, I. C., López-Morales, M., Alam, M. K., Espinoza, N., Rackham, B. V., Goyal, J. M., MacDonald, R. J., Lewis, N. K., Apai, D., Bixel, A., Jordán, A., Kirk, J., McGruder, C., Osip, D. J. 2021, The Astronomical Journal ACCESS: An Optical Transmission Spectrum of the High-gravity Hot Jupiter HAT-P-23b

Bixel, A., Apai, D. 2021, The Astronomical Journal Bioverse: A Simulation Framework to Assess the Statistical Power of Future Biosignature Surveys

Scalco, M., Bellini, A., Bedin, L. R., Anderson, J., Rosati, P., Libralato, M., Salaris, M., Vesperini, E., Nardiello, D., Apai, D., Burgasser, A. J., Gerasimov, R. 2021, Monthly Notices of the Royal Astronomical Society The HST large programme on ω Centauri - IV. catalogue of two external fields

Tannock, M.E., Metchev, S., Heinze, A., Miles-Páez, P. A., Gagné, J., Burgasser, A., Marley, M. S., Apai, D., Suárez, G., Plavchan, P. 2021, The Astronomical Journal Weather on Other Worlds. V. The Three Most Rapidly Rotating Ultra-cool Dwarfs

Zhou, Y., Bowler, B. P., Wagner, K. R., Schneider, G., Apai, D., Kraus, A. L., Close, L. M., Herczeg, G. J., Fang, M. 2021, The Astronomical Journal Hubble Space Telescope UV and Hα Measurements of the Accretion Excess Emission from the Young Giant Planet PDS 70 b

Carone, L., Mollière, P., Zhou, Y., Bouwman, J., Yan, F., Baeyens, R., Apai, D., Espinoza, N., Rackham, B. V., Jordán, A., Angerhausen, D., Decin, L., Lendl, M., Venot, O., Henning, T. 2021, Astronomy and Astrophysics Indications for very high metallicity and absence of methane in the eccentric exo-Saturn WASP-117b

Wagner, K., Boehle, A., Pathak, P., Kasper, M., Arsenault, R., Jakob, G., Käufl, U., Leveratto, S., Maire, A.-L., Pantin, E., Siebenmorgen, R., Zins, G., Absil, O., Ageorges, N., Apai, D., Carlotti, A., Choquet, É., Delacroix, C., Dohlen, K., Duhoux, P., Forsberg, P., Fuenteseca, E., Gutruf, S., Guyon, O., Huby, E., Kampf, D., Karlsson, M., Kervella, P., Kirchbauer, J.-P., Klupar, P., Kolb, J., Mawet, D., N'Diaye, M., Orban de Xivry, G., Quanz, S. P., Reutlinger, A., Ruane, G., Riquelme, M., Soenke, C., Sterzik, M., Vigan, A., de Zeeuw, T. 2021, Nature Communications Imaging low-mass planets within the habitable zone of α Centauri

Apai, D., Nardiello, D., Bedin, L. R. 2021, The Astrophysical Journal TESS Observations of the Luhman 16 AB Brown Dwarf System: Rotational Periods, Lightcurve Evolution, and Zonal Circulation

Dietrich, J., Apai, D. 2021, The Astronomical Journal An Integrated Analysis with Predictions on the Architecture of the τ Ceti Planetary System, Including a Habitable Zone Planet

Lew, Ben W. P., Apai, Dániel, Marley, Mark, Saumon, Didier, Schneider, Glenn, Zhou, Yifan, Cowan, Nicolas B., Karalidi, Theodora, Manjavacas, Elena, Bedin, L. R., & Miles-Páez, Paulo A. 2020, The Astrophysical Journal. Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf

McGruder, Chima D., López-Morales, Mercedes, Espinoza, Néstor, Rackham, Benjamin V., Apai, Dániel, Jordán, Andrés, Osip, David J., Alam, Munazza K., Bixel, Alex, Fortney, Jonathan J., Henry, Gregory W., Kirk, James, Lewis, Nikole K., Rodler, Florian, & Weaver, Ian C. 2020, The Astronomical Journal. ACCESS: Confirmation of No Potassium in the Atmosphere of WASP-31b

Tremblin, P., Phillips, M. W., Emery, A., Baraffe, I., Lew, B. W. P., Apai, D., Biller, B. A., & Bonnefoy, M. 2020, Astronomy and Astrophysics. Rotational spectral modulation of cloudless atmospheres for L/T brown dwarfs and extrasolar giant planets

Wagner, Kevin, Apai, Dániel, Kasper, Markus, McClure, Melissa, Robberto, Massimo, & Currie, Thayne 2020, The Astrophysical Journal. Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star

Yan, F., Espinoza, N., Molaverdikhani, K., Henning, Th., Mancini, L., Mallonn, M., Rackham, B. V., Apai, D., Jordán, A., Mollière, P., Chen, G., Carone, L., & Reiners, A. 2020, Astronomy and Astrophysics. LBT transmission spectroscopy of HAT-P-12b. Confirmation of a cloudy atmosphere with no significant alkali features

Dietrich, Jeremy & Apai, Dániel 2020, The Astronomical Journal. Hidden Worlds: Dynamical Architecture Predictions of Undetected Planets in Multi-planet Systems and Applications to TESS Systems

Zhou, Yifan, Bowler, Brendan P., Morley, Caroline V., Apai, Dániel, Kataria, Tiffany, Bryan, Marta L., & Benneke, Björn 2020, The Astronomical Journal. Spectral Variability of VHS J1256-1257b from 1 to 5 μm

Meusinger, H., Rudolf, C., Stecklum, B., Hoeft, M., Mauersberger, R., & Apai, D. 2020, Astronomy and Astrophysics. The galaxy population within the virial radius of the Perseus cluster

Mulders, Gijs D., O'Brien, David P., Ciesla, Fred J., Apai, Dániel, & Pascucci, Ilaria 2020, The Astrophysical Journal. Earths in Other Solar Systems' N-body Simulations: The Role of Orbital Damping in Reproducing the Kepler Planetary Systems

Bixel, Alex & Apai, Dániel 2020, The Astrophysical Journal. Testing Earthlike Atmospheric Evolution on Exo-Earths through Oxygen Absorption: Required Sample Sizes and the Advantage of Age-based Target Selection

Wagner, Kevin, Stone, Jordan, Dong, Ruobing, Ertel, Steve, Apai, Daniel, Doelman, David, Bohn, Alexander, Najita, Joan, Brittain, Sean, Kenworthy, Matthew, Keppler, Miriam, Webster, Ryan, Mailhot, Emily, & Snik, Frans 2020, The Astronomical Journal. First Images of the Protoplanetary Disk around PDS 201

Gibbs, Aidan, Bixel, Alex, Rackham, Benjamin V., Apai, Dániel, Schlecker, Martin, Espinoza, Néstor, Mancini, Luigi, Chen, Wen-Ping, Henning, Thomas, Gabor, Paul, Boyle, Richard, Perez Chavez, Jose, Mousseau, Allie, Dietrich, Jeremy, Jay Socia, Quentin, Ip, Wing, Ngeow, Chow-Choong, Tsai, An-Li, Bhandare, Asmita, Marian, Victor, Baehr, Hans, Brown, Samantha, Häberle, Maximilian, Keppler, Miriam, Molaverdikhani, Karan, & Sarkis, Paula 2020, The Astronomical Journal. EDEN: Sensitivity Analysis and Transiting Planet Detection Limits for Nearby Late Red Dwarfs

Zhou, Yifan, Apai, Dániel, Bedin, Luigi R., Lew, Ben W. P., Schneider, Glenn, Burgasser, Adam J., Manjavacas, Elena, Karalidi, Theodora, Metchev, Stanimir, Miles-Páez, Paulo A., Cowan, Nicolas B., Lowrance, Patrick J., & Radigan, Jacqueline 2020, The Astronomical Journal. Cloud Atlas: High-precision HST/WFC3/IR Time-resolved Observations of Directly Imaged Exoplanet HD 106906b

Lew, Ben W. P., Apai, Dániel, Zhou, Yifan, Radigan, Jacqueline, Marley, Mark, Schneider, Glenn, Cowan, Nicolas B., Miles-Páez, Paulo A., Manjavacas, Elena, Karalidi, Theodora, Bedin, L. R., Lowrance, Patrick J., & Burgasser, Adam J. 2020, The Astronomical Journal. Cloud Atlas: Weak Color Modulations Due to Rotation in the Planetary-mass Companion GU Psc b and 11 Other Brown Dwarfs

Kitzmann, Daniel, Heng, Kevin, Oreshenko, Maria, Grimm, Simon L., Apai, Dániel, Bowler, Brendan P., Burgasser, Adam J., & Marley, Mark S. 2020, The Astrophysical Journal. Helios-r2: A New Bayesian, Open-source Retrieval Model for Brown Dwarfs and Exoplanet Atmospheres

Weaver, Ian C., López-Morales, Mercedes, Espinoza, Néstor, Rackham, Benjamin V., Osip, David J., Apai, Dániel, Jordán, Andrés, Bixel, Alex, Lewis, Nikole K., Alam, Munazza K., Kirk, James, McGruder, Chima, Rodler, Florian, & Fienco, Jennifer 2020, The Astronomical Journal. ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of H<SUB>2</SUB>O, but No Evidence of Na or K

Bixel, Alex & Apai, Dániel 2020, The Astronomical Journal. Identifying Exo-Earth Candidates in Direct Imaging Data through Bayesian Classification

Mulders, Gijs D., Mordasini, Christoph, Pascucci, Ilaria, Ciesla, Fred J., Emsenhuber, Alexandre, & Apai, Dániel 2019, The Astrophysical Journal. The Exoplanet Population Observation Simulator. II. Population Synthesis in the Era of Kepler

Miles-Páez, Paulo A., Metchev, Stanimir, Apai, Dániel, Zhou, Yifan, Manjavacas, Elena, Karalidi, Theodora, Lew, Ben W. P., Burgasser, Adam J., Bedin, Luigi R., Cowan, Nicolas, Lowrance, Patrick J., Marley, Mark S., Radigan, Jacqueline, & Schneider, Glenn 2019, The Astrophysical Journal. Cloud Atlas: Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs

Boehle, A., Quanz, S. P., Lovis, C., Ségransan, D., Udry, S., & Apai, D. 2019, Astronomy and Astrophysics. Combining high-contrast imaging and radial velocities to constrain the planetary architectures of nearby stars

Bedin, L. R., Salaris, M., Anderson, J., Libralato, M., Apai, D., Nardiello, D., Rich, R. M., Bellini, A., Dieball, A., Bergeron, P., Burgasser, A. J., Milone, A. P., & Marino, A. F. 2019, Monthly Notices of the Royal Astronomical Society. The HST large programme on NGC 6752 - III. Detection of the peak of the white dwarf luminosity function

Leggett, S. K., Dupuy, Trent J., Morley, Caroline V., Marley, Mark S., Best, William M. J., Liu, Michael C., Apai, D., Casewell, S. L., Geballe, T. R., Gizis, John E., Pineda, J. Sebastian, Rieke, Marcia, & Wright, G. S. 2019, The Astrophysical Journal. 3.8 μm Imaging of 400-600 K Brown Dwarfs and Orbital Constraints for WISEP J045853.90+643452.6AB

Wagner, Kevin, Stone, Jordan M., Spalding, Eckhart, Apai, Daniel, Dong, Ruobing, Ertel, Steve, Leisenring, Jarron, & Webster, Ryan 2019, The Astrophysical Journal. Thermal Infrared Imaging of MWC 758 with the Large Binocular Telescope: Planetary-driven Spiral Arms?

Apai, Dániel, Milster, Tom D., Kim, Dae Wook, Bixel, Alex, Schneider, Glenn, Liang, Ronguang, & Arenberg, Jonathan 2019, The Astronomical Journal. A Thousand Earths: A Very Large Aperture, Ultralight Space Telescope Array for Atmospheric Biosignature Surveys

Zhou, Yifan, Apai, Dániel, Lew, Ben W. P., Schneider, Glenn, Manjavacas, Elena, Bedin, Luigi R., Cowan, Nicolas B., Marley, Mark S., Radigan, Jacqueline, Karalidi, Theodora, Lowrance, Patrick J., Miles-Páez, Paulo A., Metchev, Stanimir, & Burgasser, Adam J. 2019, The Astronomical Journal. Erratum: “Cloud Atlas: High-contrast Time-resolved Observations of Planetary-mass Companions” (<A href="https://doi.org/10.3847/1538-3881/ab037f">2019, AJ, 157, 128</A>)

Wagner, Kevin, Apai, Dániel, & Kratter, Kaitlin M. 2019, The Astrophysical Journal. On the Mass Function, Multiplicity, and Origins of Wide-orbit Giant Planets

Milone, A. P., Marino, A. F., Bedin, L. R., Anderson, J., Apai, D., Bellini, A., Dieball, A., Salaris, M., Libralato, M., Nardiello, D., Bergeron, P., Burgasser, A. J., Rees, J. M., Rich, R. M., & Richer, H. B. 2019, Monthly Notices of the Royal Astronomical Society. The HST Large Programme on NGC 6752 - II. Multiple populations at the bottom of the main sequence probed in NIR

Manjavacas, Elena, Apai, Dániel, Lew, Ben W. P., Zhou, Yifan, Schneider, Glenn, Burgasser, Adam J., Karalidi, Theodora, Miles-Páez, Paulo A., Lowrance, Patrick J., Cowan, Nicolas, Bedin, Luigi R., Marley, Mark S., Metchev, Stan, & Radigan, Jacqueline 2019, The Astrophysical Journal. Cloud Atlas: Rotational Spectral Modulations and Potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C

Bedin, L. R., Salaris, M., Rich, R. M., Richer, H., Anderson, J., Bettoni, D., Nardiello, D., Milone, A. P., Marino, A. F., Libralato, M., Bellini, A., Dieball, A., Bergeron, P., Burgasser, A. J., & Apai, D. 2019, Monthly Notices of the Royal Astronomical Society. The HST Large Programme on NGC 6752. I. Serendipitous discovery of a dwarf Galaxy in background

Zhou, Yifan, Apai, Dániel, Lew, Ben W. P., Schneider, Glenn, Manjavacas, Elena, Bedin, Luigi R., Cowan, Nicolas B., Marley, Mark S., Radigan, Jacqueline, Karalidi, Theodora, Lowrance, Patrick J., Miles-Páez, Paulo A., Metchev, Stanimir, & Burgasser, Adam J. 2019, The Astronomical Journal. Cloud Atlas: High-contrast Time-resolved Observations of Planetary-mass Companions

Manjavacas, Elena, Apai, Dániel, Zhou, Yifan, Lew, Ben W. P., Schneider, Glenn, Metchev, Stan, Miles-Páez, Paulo A., Radigan, Jacqueline, Marley, Mark S., Cowan, Nicolas, Karalidi, Theodora, Burgasser, Adam J., Bedin, Luigi R., Lowrance, Patrick J., & Kauffmann, Parker 2019, The Astronomical Journal. Cloud Atlas: Hubble Space Telescope Near-infrared Spectral Library of Brown Dwarfs, Planetary-mass Companions, and Hot Jupiters

Rackham, Benjamin V., Apai, Dániel, & Giampapa, Mark S. 2019, The Astronomical Journal. The Transit Light Source Effect. II. The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars

Bixel, Alex, Rackham, Benjamin V., Apai, Dániel, Espinoza, Néstor, López-Morales, Mercedes, Osip, David, Jordán, Andrés, McGruder, Chima, & Weaver, Ian 2019, The Astronomical Journal. ACCESS: Ground-based Optical Transmission Spectroscopy of the Hot Jupiter WASP-4b

Espinoza, Néstor, Rackham, Benjamin V., Jordán, Andrés, Apai, Dániel, López-Morales, Mercedes, Osip, David J., Grimm, Simon L., Hoeijmakers, Jens, Wilson, Paul A., Bixel, Alex, McGruder, Chima, Rodler, Florian, Weaver, Ian, Lewis, Nikole K., Fortney, Jonathan J., & Fraine, Jonathan 2019, Monthly Notices of the Royal Astronomical Society. ACCESS: a featureless optical transmission spectrum for WASP-19b from Magellan/IMACS

Gibbs, Aidan, Wagner, Kevin, Apai, Daniel, Moór, Attila, Currie, Thayne, Bonnefoy, Mickäel, Langlois, Maud, & Lisse, Carey 2019, The Astronomical Journal. VLT/SPHERE Multiwavelength High-contrast Imaging of the HD 115600 Debris Disk: New Constraints on the Dust Geometry and the Presence of Young Giant Planets