Infrared: planetary systems; Methods: data analysis; Methods: observational; Planets and satellites: atmospheres; Techniques: image processing
Abstract :
[en] Context. The newly accessible mid-infrared (MIR) window offered by the James Webb Space Telescope (JWST) for exoplanet imaging is expected to provide valuable information to characterize their atmospheres. In particular, coronagraphs on board the JWST Mid-InfraRed instrument (MIRI) are capable of imaging the coldest directly imaged giant planets at the wavelengths where they emit most of their flux. The MIRI coronagraphs have been specially designed to detect the NH3 absorption around 10.5 μm, which has been predicted by atmospheric models and should be detectable for planets colder than 1200 K. Aims. We aim to assess the presence of NH3 while refining the atmospheric parameters of one of the coldest companions detected by directly imaging GJ 504 b. Its mass is still a matter of debate and depending on the host star age estimate, the companion could either be placed in the brown dwarf regime of ~20 MJup or in the young Jovian planet regime of ~4 MJup. Methods. We present an analysis of new MIRI observations, using the coronagraphic filters F1065C, F1140C, and F1550C of the GJ 504 system. We took advantage of previous observations of reference stars to build a library of images and to perform a more efficient subtraction of the stellar diffraction pattern. We used an atmospheric grid from the Exo-REM model to refine the atmospheric parameters by combining archival near-infrared (NIR) photometry with the MIR photometry. Results. We detected the presence of NH3 at 12.5 σ and measured its volume mixing ratio of 10- 5.3±0.07 in the atmosphere of GJ 504 b. These results are in line with atmospheric model expectations for a planetary-mass object and observed in brown dwarfs within a similar temperature range. The best-fit model with Exo-REM provides updated values of its atmospheric parameters, yielding a temperature of Teff = 512 ± 10 K and radius of R = 1.08- 0.03+0.04 RJup. Conclusions. These observations demonstrate the capability of MIRI coronagraphs to detect NH3 and to provide the first MIR observations of one of the coldest directly imaged companions. Overall, NH3 is a key molecule for characterizing the atmospheres of cold planets, offering valuable insights into their surface gravity. These observations provide valuable information for future spectroscopic observations planned with JWST, in particular, with the MIRI medium-resolution spectrometer (MRS), which will allow us to characterize the atmosphere of GJ 504 b in depth.
Research Center/Unit :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Mâlin, Mathilde ; Department of Physics and Astronomy, Johns Hopkins University, Baltimore, United States ; Space Telescope Science Institute, Baltimore, United States ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
Boccaletti, Anthony ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
Perrot, Clément ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
Baudoz, Pierre ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
Rouan, Daniel ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
Lagage, Pierre-Olivier; Université Paris-Saclay, Université Paris Cité, Cea, Cnrs, Aim, Gif-sur-Yvette, France
Waters, Rens ; Department of Astrophysics/IMAPP, Radboud University, Nijmegen, Netherlands ; Hfml -FELIX., Radboud University, Nijmegen, Netherlands ; Sron Netherlands Institute for Space Research, Leiden, Netherlands
Güdel, Manuel ; Department of Astrophysics, University of Vienna, Vienna, Austria ; Eth Zürich, Institute for Particle Physics and Astrophysics, Zürich, Switzerland
Henning, Thomas ; Max-Planck-Institut für Astronomie (MPIA), Heidelberg, Germany
Vandenbussche, Bart ; Institute of Astronomy, Ku Leuven, Leuven, Belgium
Absil, Olivier ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
Barrado, David ; Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain
Charnay, Benjamin ; Lira, Observatoire de Paris, Université Psl, Sorbonne Université, Université Paris Cité, Cy Cergy Paris Université, Cnrs, Meudon, France
This work is based on observations made with the NASA/ESA/CSA JamesWebb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #1277. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contrast with NASA (80NM0018D0004). This publication makes use of VOSA, developed under the Spanish Virtual Observatory (https://svo.cab.inta-csic.es) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020- 112949GB-I00. VOSA has been partially updated by using funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no 776403 (EXOPLANETS-A) This work has benefitted from The UltracoolSheet at http://bit.ly/UltracoolSheet, maintained by Will Best, Trent Dupuy, Michael Liu, Aniket Sanghi, Rob Siverd, and Zhoujian Zhang, and developed from compilations by Dupuy & Liu (2012), Dupuy & Kraus (2013), Deacon et al. (2014), Liu et al. (2016), Best et al. (2018), Best et al. (2021), Sanghi et al. (2023), and Schneider et al. (2023). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/ gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI : 10.26093/cds/vizier). The original description of the VizieR service was published in 2000, A&AS 143, 23 Software: python, astropy, numpy, scipy matplotlib. M.M., A.B., P.-O.L., C.C. acknowledges funding support by CNES. B.V. thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. O.A. is a Senior Research Associate of the Fonds de la Recherche Scientifique - FNRS. OA thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. D.B. is supported by Spanish MCIN/AEI/10.13039/501100011033 grant PID2019-107061GB-C61 and No. MDM-2017-0737. L.D. acknowledges funding from the KU Leuven Interdisciplinary Grant (IDN/19/028), the European Union H2020-MSCA-ITN- 2019 under Grant no. 860470 (CHAMELEON) and the FWO research grant G086217N. MPIA acknowledges support from the Federal Ministry of Economy (BMWi) through the German Space Agency (DLR). J.P. acknowledges financial support from the UK Science and Technology Facilities Council, and the UK Space Agency. G.O. acknowledge support from the Swedish National Space Board and the Knut and Alice Wallenberg Foundation. P.P. thanks the Swiss National Science Foundation (SNSF) for financial support under grant number 200020_200399. P.R. thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. E.C. acknowledges funding by the European Union (ERC, ESCAPE, project No 101044152). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. C.D. acknowledges support from the INAF initiative \"IAF Astronomy Fellowships in Italy\", grant name GExoLife. E.v.D. acknowledges support from A-ERC grant 101019751 MOLDISK. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. TRG is grateful for support from the Carlsberg Foundation via grant No. CF20-0534. T.P.R. acknowledges support from the ERC 743029 EASY. Support from SNSA is acknowledged.This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #1277. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contrast with NASA (80NM0018D0004). This publication makes use of VOSA, developed under the Spanish Virtual Observatory ( https://svo.cab.inta-csic.es ) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020- 112949GB-I00. VOSA has been partially updated by using funding from the European Union\u2019s Horizon 2020 Research and Innovation Programme, under Grant Agreement n\u00BA 776403 (EXOPLANETS-A) This work has benefitted from The UltracoolSheet at h ttp://bit.ly/UltracoolSheet , maintained by Will Best, Trent Dupuy, Michael Liu, Aniket Sanghi, Rob Siverd, and Zhoujian Zhang, and developed from compilations by Dupuy & Liu (2012), Dupuy & Kraus (2013), Deacon et al. (2014), Liu et al. (2016), Best et al. (2018), Best et al. (2021), Sanghi et al. (2023), and Schneider et al. (2023). This work has made use of data from the European Space Agency (ESA) mission Gaia ( https://www.cosmos.esa.int/gaia ), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI : 10.26093/cds/vizier ). The original description of the VizieR service was published in 2000, A&AS 143, 23 Software: python, astropy, numpy, scipy matplotlib. M.M., A.B., P.-O.L., C.C. acknowledges funding support by CNES. B.V. thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. O.A. is a Senior Research Associate of the Fonds de la Recherche Scientifique \u2013 FNRS. OA thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. D.B. is supported by Spanish MCIN/AEI/10.13039/501100011033 grant PID2019-107061GB-C61 and No. MDM-2017-0737. L.D. acknowledges funding from the KU Leuven Interdisciplinary Grant (IDN/19/028), the European Union H2020-MSCA-ITN- 2019 under Grant no. 860470 (CHAMELEON) and the FWO research grant G086217N. MPIA acknowledges support from the Federal Ministry of Economy (BMWi) through the German Space Agency (DLR). J.P. acknowledges financial support from the UK Science and Technology Facilities Council, and the UK Space Agency. G.O. acknowledge support from the Swedish National Space Board and the Knut and Alice Wallenberg Foundation. P.P. thanks the Swiss National Science Foundation (SNSF) for financial support under grant number 200020_200399. P.R. thanks the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. E.C. acknowledges funding by the European Union (ERC, ESCAPE, project No 101044152). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. C.D. acknowledges support from the INAF initiative \u201CIAF Astronomy Fellowships in Italy\u201D, grant name GExoLife. E.v.D. acknowledges support from A-ERC grant 101019751 MOLDISK. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. TRG is grateful for support from the Carlsberg Foundation via grant No. CF20-0534. T.P.R. acknowledges support from the ERC 743029 EASY. Support from SNSA is acknowledged.
Commentary :
Copyright ESO 2025, published by EDP Sciences - https://www.aanda.org/articles/aa/full_html/2025/01/aa52695-24/aa52695-24.html
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