Examinando por Autor "Tsai, Shang-Min"

Mostrando 1 - 2 de 2
  • No hay miniatura disponible
    Ítem
    A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b
    (Nature Research, 2023-08) Coulombe, Louis-Philippe; Benneke, Björn; Challener, Ryan; Piette, Anjali A. A.; Wiser, Lindsey S.; Mansfield, Megan; MacDonald, Ryan J.; Beltz, Hayley; Feinstein, Adina D.; Radica, Michael; Savel, Arjun B.; Dos Santos, Leonardo A.; Bean, Jacob L.; Parmentier, Vivien; Wong, Ian; Rauscher, Emily; Komacek, Thaddeus D.; Kempton, Eliza M.-R.; Tan, Xianyu; Hammond, Mark; Lewis, Neil T.; Line, Michael R.; Lee, Elspeth K. H.; Shivkumar, Hinna; Crossfield, Ian J. M.; Nixon, Matthew C.; Rackham, Benjamin V.; Wakeford, Hannah R.; Welbanks, Luis; Zhang, Xi; Batalha, Natalie M.; Berta-Thompson, Zachory K.; Changeat, Quentin; Désert, Jean-Michel; Espinoza, Néstor; Goyal, Jayesh M.; Harrington, Joseph; Knutson, Heather A.; Kreidberg, Laura; López-Morales, Mercedes; Shporer, Avi; Sing, David K.; Stevenson, Kevin B.; Aggarwal, Keshav; Ahrer, Eva-Maria; Alam, Munazza K.; Bell, Taylor J.; Blecic, Jasmina; Caceres, Claudio; Carter, Aarynn L.; Casewell, Sarah L.; Crouzet, Nicolas; Cubillos, Patricio E.; Decin, Leen; Fortney, Jonathan J.; Gibson, Neale P.; Heng, Kevin; Henning, Thomas; Iro, Nicolas; Kendrew, Sarah; Lagage, Pierre-Olivier; Leconte, Jérémy; Lendl, Monika; Lothringer, Joshua D.; Mancini, Luigi; Mikal-Evans, Thomas; Molaverdikhani, Karan; Nikolov, Nikolay K.; Ohno, Kazumasa; Palle, Enric; Piaulet, Caroline; Redfield, Seth; Roy, Pierre-Alexis; Tsai, Shang-Min; Venot, Olivia; Wheatley, Peter J.
    Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope 1–3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis 3–12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS 13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H=1.03−0.51+1.11 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators. © 2023, The Author(s).
  • No hay miniatura disponible
    Ítem
    Sulfur dioxide in the mid-infrared transmission spectrum of WASP-39b
    (Nature Research, 2024-12) Powell, Diana; Feinstein, Adina D.; Lee, Elspeth K. H.; Zhang, Michael; Tsai, Shang-Min; Taylor, Jake; Kirk, James; Bell, Taylor; Barstow, Joanna; Gao, Peter; Bean, Jacob; Blecic, Jasmina; Chubb, Katy L.; Crossfield, Ian J. M.; Jordan, Sean; Kitzmann, Daniel; Moran, Sarah E.; Morello, Giuseppe; Moses, Julianne; Welbanks, Luis; Yang, Jeehyun; Zhang, Xi; Ahrer, Eva-Maria; Bello-Arufe, Aaron; Brande, Jonathan; Casewell S.L.; Crouzet, Nicolas; Cubillos, Patricio E.; Demory, Brice-Olivier; Dyrek, Achrène; Flagg, Laura; Hu, Renyu; Inglis, Julie; Jones, Kathryn D.; Kreidberg, Laura; López-Morales, Mercedes; Lagage, Pierre-Olivier; Meier Valdés, Erik A.; Miguel, Yamila; Parmentier, Vivien; Piette, Anjali A. A.; Rackham, Benjamin V.; Radica, Michael; Redfield, Seth; Stevenson, Kevin B.; Wakeford, Hannah R.; Aggarwal, Keshav; Alam, Munazza K.; Batalha, Natalie M.; Batalha, Natasha E.; Benneke, Björn; Berta-Thompson, Zach K.; Brady, Ryan P.; Caceres, Claudio; Carter, Aarynn L.; Désert, Jean-Michel; Harrington, Joseph; Iro, Nicolas; Line, Michael R.; Lothringer, Joshua D.; MacDonald, Ryan J.; Mancini, Luigi; Molaverdikhani, Karan; Mukherjee, Sagnick; Nixon, Matthew C.; Oza, Apurva V.; Palle, Enric; Rustamkulov, Zafar; Sing, David K.; Steinrueck, Maria E.; Venot, Olivia; Wheatley, Peter J.; Yurchenko, Sergei N.
    The recent inference of sulfur dioxide (SO2) in the atmosphere of the hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1–3 suggests that photochemistry is a key process in high-temperature exoplanet atmospheres4. This is because of the low (<1 ppb) abundance of SO2 under thermochemical equilibrium compared with that produced from the photochemistry of H2O and H2S (1–10 ppm)4–9. However, the SO2 inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.05 μm and, therefore, the detection of other SO2 absorption bands at different wavelengths is needed to better constrain the SO2 abundance. Here we report the detection of SO2 spectral features at 7.7 and 8.5 μm in the 5–12-μm transmission spectrum of WASP-39b measured by the JWST Mid-Infrared Instrument (MIRI) Low Resolution Spectrometer (LRS)10. Our observations suggest an abundance of SO2 of 0.5–25 ppm (1σ range), consistent with previous findings4. As well as SO2, we find broad water-vapour absorption features, as well as an unexplained decrease in the transit depth at wavelengths longer than 10 μm. Fitting the spectrum with a grid of atmospheric forward models, we derive an atmospheric heavy-element content (metallicity) for WASP-39b of approximately 7.1–8.0 times solar and demonstrate that photochemistry shapes the spectra of WASP-39b across a broad wavelength range.