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Start Over Author "Kai Hou" Publisher american astronomical society
14 results on '"Kai Hou"'

1. Exploring the Ability of Hubble Space Telescope WFC3 G141 to Uncover Trends in Populations of Exoplanet Atmospheres through a Homogeneous Transmission Survey of 70 Gaseous Planets

Author

Edwards, Billy, primary, Changeat, Quentin, additional, Tsiaras, Angelos, additional, Yip, Kai Hou, additional, Al-Refaie, Ahmed F., additional, Anisman, Lara, additional, Bieger, Michelle F., additional, Gressier, Amélie, additional, Shibata, Sho, additional, Skaf, Nour, additional, Bouwman, Jeroen, additional, Cho, James Y-K., additional, Ikoma, Masahiro, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, Lagage, Pierre-Olivier, additional, and Tinetti, Giovanna, additional

Published
2023
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2. Characterizing a World Within the Hot-Neptune Desert: Transit Observations of LTT 9779 b with the Hubble Space Telescope/WFC3

Author

Edwards, Billy, primary, Changeat, Quentin, additional, Tsiaras, Angelos, additional, Allan, Andrew, additional, Behr, Patrick, additional, Hagey, Simone R., additional, Himes, Michael D., additional, Ma, Sushuang, additional, Stassun, Keivan G., additional, Thomas, Luis, additional, Thompson, Alexandra, additional, Boley, Aaron, additional, Booth, Luke, additional, Bouwman, Jeroen, additional, France, Kevin, additional, Lowson, Nataliea, additional, Meech, Annabella, additional, Phillips, Caprice L., additional, Vidotto, Aline A., additional, Yip, Kai Hou, additional, Bieger, Michelle, additional, Gressier, Amélie, additional, Janin, Estelle, additional, Jiang, Ing-Guey, additional, Leonardi, Pietro, additional, Sarkar, Subhajit, additional, Skaf, Nour, additional, Taylor, Jake, additional, Yang, Ming, additional, and Ward-Thompson, Derek, additional

Published
2023
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4. ARES.* V. No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b

Author

Mugnai, Lorenzo V., primary, Modirrousta-Galian, Darius, additional, Edwards, Billy, additional, Changeat, Quentin, additional, Bouwman, Jeroen, additional, Morello, Giuseppe, additional, Al-Refaie, Ahmed, additional, Baeyens, Robin, additional, Bieger, Michelle Fabienne, additional, Blain, Doriann, additional, Gressier, Amélie, additional, Guilluy, Gloria, additional, Jaziri, Yassin, additional, Kiefer, Flavien, additional, Morvan, Mario, additional, Pluriel, William, additional, Poveda, Mathilde, additional, Skaf, Nour, additional, Whiteford, Niall, additional, Wright, Sam, additional, Yip, Kai Hou, additional, Zingales, Tiziano, additional, Charnay, Benjamin, additional, Drossart, Pierre, additional, Leconte, Jérémy, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, and Beaulieu, Jean-Philippe, additional

Published
2021
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5. ARES I: WASP-76 b, A Tale of Two HST Spectra

Author

Sam Wright, Angelos Tsiaras, Mario Morvan, Mathilde Poveda, Ahmed Al-Refaie, Pierre Drossart, Gloria Guilluy, Amélie Gressier, Olivia Venot, William Pluriel, Lorenzo V. Mugnai, Flavien Kiefer, Tiziano Zingales, Niall Whiteford, Robin Baeyens, Ingo Waldmann, Billy Edwards, Adam Yassin Jaziri, Jean-Philippe Beaulieu, Darius Modirrousta-Galian, Doriann Blain, Jake Taylor, Quentin Changeat, Nour Skaf, Benjamin Charnay, Michelle Fabienne Bieger, Jérémy Leconte, Kai Hou Yip, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Dipartimento di Fisica [Torino], Università degli studi di Torino (UNITO), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), ECLIPSE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Palermo (OAPa), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, Department of Physics [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Centre for Exoplanet Science, School of Physical Sciences [Hobart], University of Tasmania [Hobart, Australia] (UTAS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), and Dipartimento di Fisica [Roma La Sapienza]

Subjects
Brightness, 010504 meteorology & atmospheric sciences, Exoplanet atmospheres, Exoplanet atmospheric composition, Hubble Space Telescope, Astrophysics - Earth and Planetary Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Spectral line, Atmosphere, Jupiter, HAT-P-7B, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, MOLECULAR LINE LISTS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, HOT, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Science & Technology, Astronomy and Astrophysics, ATMOSPHERE, GIANT EXOPLANET, Grism, RESOLUTION, Transmission (telecommunications), 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Physical Sciences, INFERENCE, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Wide Field Camera 3, STARS
Abstract

We analyse the transmission and emission spectra of the ultra-hot Jupiter WASP-76b, observed with the G141 grism of the Hubble Space Telescope's Wide Field Camera 3 (WFC3). We reduce and fit the raw data for each observation using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available analysis suite TauRex 3. Previous studies of the WFC3 transmission spectra of WASP-76 b found hints of titanium oxide (TiO) and vanadium oxide (VO) or non-grey clouds. Accounting for a fainter stellar companion to WASP-76, we reanalyse this data and show that removing the effects of this background star changes the slope of the spectrum, resulting in these visible absorbers no longer being detected, eliminating the need for a non-grey cloud model to adequately fit the data but maintaining the strong water feature previously seen. However, our analysis of the emission spectrum suggests the presence of TiO and an atmospheric thermal inversion, along with a significant amount of water. Given the brightness of the host star and the size of the atmospheric features, WASP-76 b is an excellent target for further characterisation with HST, or with future facilities, to better understand the nature of its atmosphere, to confirm the presence of TiO and to search for other optical absorbers., Accepted for publication in AJ

Published
2020

6. Peeking inside the Black Box: Interpreting Deep-learning Models for Exoplanet Atmospheric Retrievals

Author

Nikolaos Nikolaou, Giovanna Tinetti, Kai Hou Yip, Mario Morvan, Billy Edwards, Ingo Waldmann, and Quentin Changeat

Subjects
Physics, business.industry, Deep learning, 05 social sciences, 050301 education, Astronomy and Astrophysics, Machine learning, computer.software_genre, 01 natural sciences, Exoplanet, Field (computer science), Nonlinear system, Space and Planetary Science, 0103 physical sciences, Deep neural networks, Artificial intelligence, Sensitivity (control systems), business, 010303 astronomy & astrophysics, 0503 education, computer, Interpretability
Abstract

Deep-learning algorithms are growing in popularity in the field of exoplanetary science due to their ability to model highly nonlinear relations and solve interesting problems in a data-driven manner. Several works have attempted to perform fast retrievals of atmospheric parameters with the use of machine-learning algorithms like deep neural networks (DNNs). Yet, despite their high predictive power, DNNs are also infamous for being "black boxes." It is their apparent lack of explainability that makes the astrophysics community reluctant to adopt them. What are their predictions based on? How confident should we be in them? When are they wrong, and how wrong can they be? In this work, we present a number of general evaluation methodologies that can be applied to any trained model and answer questions like these. In particular, we train three different popular DNN architectures to retrieve atmospheric parameters from exoplanet spectra and show that all three achieve good predictive performance. We then present an extensive analysis of the predictions of DNNs, which can inform us–among other things–of the credibility limits for atmospheric parameters for a given instrument and model. Finally, we perform a perturbation-based sensitivity analysis to identify to which features of the spectrum the outcome of the retrieval is most sensitive. We conclude that, for different molecules, the wavelength ranges to which the DNNs predictions are most sensitive do indeed coincide with their characteristic absorption regions. The methodologies presented in this work help to improve the evaluation of DNNs and to grant interpretability to their predictions.

Published
2021

8. ARES IV: Probing the Atmospheres of the Two Warm Small Planets HD 106315c and HD 3167c with the HST/WFC3 Camera

Author

Guilluy, Gloria, primary, Gressier, Amélie, additional, Wright, Sam, additional, Santerne, Alexandre, additional, Jaziri, Adam Yassin, additional, Edwards, Billy, additional, Changeat, Quentin, additional, Modirrousta-Galian, Darius, additional, Skaf, Nour, additional, Al-Refaie, Ahmed, additional, Baeyens, Robin, additional, Bieger, Michelle Fabienne, additional, Blain, Doriann, additional, Kiefer, Flavien, additional, Morvan, Mario, additional, Mugnai, Lorenzo V., additional, Pluriel, William, additional, Poveda, Mathilde, additional, Zingales, Tiziano, additional, Whiteford, Niall, additional, Yip, Kai Hou, additional, Charnay, Benjamin, additional, Leconte, Jérémy, additional, Drossart, Pierre, additional, Sozzetti, Alessandro, additional, Marcq, Emmanuel, additional, Tsiaras, Angelos, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, and Beaulieu, Jean-Philippe, additional

Published
2020
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10. ARES. III. Unveiling the Two Faces of KELT-7 b with HST WFC3

Author

Pluriel, William, primary, Whiteford, Niall, additional, Edwards, Billy, additional, Changeat, Quentin, additional, Yip, Kai Hou, additional, Baeyens, Robin, additional, Al-Refaie, Ahmed, additional, Fabienne Bieger, Michelle, additional, Blain, Dorian, additional, Gressier, Amélie, additional, Guilluy, Gloria, additional, Yassin Jaziri, Adam, additional, Kiefer, Flavien, additional, Modirrousta-Galian, Darius, additional, Morvan, Mario, additional, Mugnai, Lorenzo V., additional, Poveda, Mathilde, additional, Skaf, Nour, additional, Zingales, Tiziano, additional, Wright, Sam, additional, Charnay, Benjamin, additional, Drossart, Pierre, additional, Leconte, Jérémy, additional, Tsiaras, Angelos, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, and Beaulieu, Jean-Philippe, additional

Published
2020
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11. ARES. II. Characterizing the Hot Jupiters WASP-127 b, WASP-79 b, and WASP-62b with the Hubble Space Telescope

Author

Skaf, Nour, primary, Bieger, Michelle Fabienne, additional, Edwards, Billy, additional, Changeat, Quentin, additional, Morvan, Mario, additional, Kiefer, Flavien, additional, Blain, Doriann, additional, Zingales, Tiziano, additional, Poveda, Mathilde, additional, Al-Refaie, Ahmed, additional, Baeyens, Robin, additional, Gressier, Amélie, additional, Guilluy, Gloria, additional, Jaziri, Adam Yassin, additional, Modirrousta-Galian, Darius, additional, Mugnai, Lorenzo V., additional, Pluriel, William, additional, Whiteford, Niall, additional, Wright, Sam, additional, Yip, Kai Hou, additional, Charnay, Benjamin, additional, Leconte, Jérémy, additional, Drossart, Pierre, additional, Tsiaras, Angelos, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, and Beaulieu, Jean-Philippe, additional

Published
2020
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12. Original Research by Young Twinkle Students (Orbyts): Ephemeris Refinement of Transiting Exoplanets II

Author

Edwards, Billy, primary, Anisman, Lara, additional, Changeat, Quentin, additional, Morvan, Mario, additional, Wright, Sam, additional, Yip, Kai Hou, additional, Abdullahi, Amiira, additional, Ali, Jesmin, additional, Amofa, Clarry, additional, Antoniou, Antony, additional, Arzouni, Shahad, additional, Bradley, Noeka, additional, Campana, Dayanara, additional, Chavda, Nandini, additional, Creswell, Jessy, additional, Gazieva, Neliman, additional, Gudgeon-Sidelnikova, Emily, additional, Guha, Pratap, additional, Hayden, Ella, additional, Huda, Mohammed, additional, Hussein, Hana, additional, Ibrahim, Ayub, additional, Ike, Chika, additional, Jama, Salma, additional, Joshi, Bhavya, additional, Kc, Schet, additional, Keenan, Paris, additional, Kelly-Smith, Charlie, additional, Khan, Aziza, additional, Korodimos, George, additional, Liang, Jiale, additional, Nogueira, Guilherme Luis, additional, Martey-Botchway, Neil, additional, Masruri, Asan, additional, Miyamaru, Osuke, additional, Moalin, Ismail, additional, Monteiro, Fabiana, additional, Nawrocka, Adrianna, additional, Musa, Sebri, additional, Nelson, Lilith, additional, Ogunjuyigbe, Isabel, additional, Patel, Jaymit, additional, Pereira, Joesph, additional, Ramsey, James, additional, Rasoul, Billnd, additional, Reetsong, Tumo, additional, Saeed, Haad, additional, Sander, Cameron, additional, Sanetra, Matthew, additional, Tarabe, Zainab, additional, Tareke, Milcah, additional, Tasneem, Nazifa, additional, Teo, Meigan, additional, Uddin, Asiyah, additional, Upadhyay, Kanvi, additional, Yanakiev, Kaloyan, additional, Yatingiri, Deepakgiri, additional, Dunn, William, additional, Kokori, Anatasia, additional, Tsiaras, Angelos, additional, Gomez, Edward, additional, Tinetti, Giovanna, additional, and Tennyson, Jonathan, additional

Published
2020
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13. ARES I: WASP-76 b, A Tale of Two HST Spectra

Author

Edwards, Billy, primary, Changeat, Quentin, additional, Baeyens, Robin, additional, Tsiaras, Angelos, additional, Al-Refaie, Ahmed, additional, Taylor, Jake, additional, Yip, Kai Hou, additional, Bieger, Michelle Fabienne, additional, Blain, Doriann, additional, Gressier, Amélie, additional, Guilluy, Gloria, additional, Jaziri, Adam Yassin, additional, Kiefer, Flavien, additional, Modirrousta-Galian, Darius, additional, Morvan, Mario, additional, Mugnai, Lorenzo V., additional, Pluriel, William, additional, Poveda, Mathilde, additional, Skaf, Nour, additional, Whiteford, Niall, additional, Wright, Sam, additional, Zingales, Tiziano, additional, Charnay, Benjamin, additional, Drossart, Pierre, additional, Leconte, Jérémy, additional, Venot, Olivia, additional, Waldmann, Ingo, additional, and Beaulieu, Jean-Philippe, additional

Published
2020
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14. Hubble WFC3 Spectroscopy of the Habitable-zone Super-Earth LHS 1140 b

Author

Angelos Tsiaras, Quentin Changeat, Mayuko Mori, Billy Edwards, Ahmed Al-Refaie, Lara O. Anisman, Mario Morvan, Ingo Waldmann, Kai Hou Yip, and Giovanna Tinetti

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, 010504 meteorology & atmospheric sciences, Planetary habitability, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Exoplanet, Physics::Geophysics, Grism, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Circumstellar habitable zone, Wide Field Camera 3, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

Atmospheric characterisation of temperate, rocky planets is the holy grail of exoplanet studies. These worlds are at the limits of our capabilities with current instrumentation in transmission spectroscopy and challenge our state-of-the-art statistical techniques. Here we present the transmission spectrum of the temperate Super-Earth LHS 1140b using the Hubble Space Telescope (HST). The Wide Field Camera 3 (WFC3) G141 grism data of this habitable zone (T$_{\rm{eq}}$ = 235 K) Super-Earth (R = 1.7 $R_\oplus$), shows tentative evidence of water. However, the signal-to-noise ratio, and thus the significance of the detection, is low and stellar contamination models can cause modulation over the spectral band probed. We attempt to correct for contamination using these models and find that, while many still lead to evidence for water, some could provide reasonable fits to the data without the need for molecular absorption although most of these cause also features in the visible ground-based data which are nonphysical. Future observations with the James Webb Space Telescope (JWST) would be capable of confirming, or refuting, this atmospheric detection., Accepted for publication in AJ on 30th October 2020

Published
2020

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