High-precision atmospheric characterization of a Y dwarf with JWST NIRSpec G395H spectroscopy: isotopologue, C/O ratio, metallicity, and the abundances of six molecular species
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| Autores principales: | , , , , , , , , , , , , , , , , , , , , , |
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| Formato: | Preprint |
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2024
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| _version_ | 1866910323122896896 |
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| author | Lew, Ben W. P. Roellig, Thomas Batalha, Natasha E. Line, Michael Greene, Thomas Murkherjee, Sagnick Freedman, Richard Meyer, Michael Beichman, Charles De Oliveira, Catarina Alves De Furio, Matthew Johnstone, Doug Greenbaum, Alexandra Z. Marley, Mark Fortney, Jonathan J. Young, Erick T. Leisenring, Jarron Boyer, Martha Hodapp, Klaus Misselt, Karl Stansberry, John Rieke, Marcia |
| author_facet | Lew, Ben W. P. Roellig, Thomas Batalha, Natasha E. Line, Michael Greene, Thomas Murkherjee, Sagnick Freedman, Richard Meyer, Michael Beichman, Charles De Oliveira, Catarina Alves De Furio, Matthew Johnstone, Doug Greenbaum, Alexandra Z. Marley, Mark Fortney, Jonathan J. Young, Erick T. Leisenring, Jarron Boyer, Martha Hodapp, Klaus Misselt, Karl Stansberry, John Rieke, Marcia |
| contents | The launch of the James Webb Space Telescope (JWST) marks a pivotal moment for precise atmospheric characterization of Y dwarfs, the coldest brown dwarf spectral type. In this study, we leverage moderate spectral resolution observations (R $\sim$ 2700) with the G395H grating of the Near-Infrared Spectrograph (NIRSpec) onboard of JWST to characterize the nearby (9.9 pc) Y dwarf WISEPA J182831.08+265037.8 (WISE 1828). With the NIRSpec G395H 2.88-5.12 $\mathrmμ$m spectrum, we measure the abundances of CO, CO$_2$, CH$_4$, H$_2$S, NH$_3$, and H$_2$O, which are the major carbon, nitrogen, oxygen, and sulfur bearing species in the atmosphere. Based on the retrieved volume mixing ratios with the atmospheric retrieval framework CHIMERA, we report that the C/O ratio is $0.45 \pm 0.01$, close to the solar C/O value of 0.55, and the metallicity to be +0.30 $\pm$ 0.02 dex. Comparison between the retrieval results with the forward modeling results suggests that the model bias for C/O and metallicity could be as high as 0.03 and 0.97 dex respectively. We also report a lower limit of the $^{12}$CO/$^{13}$CO ratio of $>40 $, being consistent with the nominal solar value of 90. Our results highlight the potential of JWST in measuring the C/O ratios down to percent-level precision and characterizing isotopologues of cold planetary atmospheres similar to WISE 1828. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_05900 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | High-precision atmospheric characterization of a Y dwarf with JWST NIRSpec G395H spectroscopy: isotopologue, C/O ratio, metallicity, and the abundances of six molecular species Lew, Ben W. P. Roellig, Thomas Batalha, Natasha E. Line, Michael Greene, Thomas Murkherjee, Sagnick Freedman, Richard Meyer, Michael Beichman, Charles De Oliveira, Catarina Alves De Furio, Matthew Johnstone, Doug Greenbaum, Alexandra Z. Marley, Mark Fortney, Jonathan J. Young, Erick T. Leisenring, Jarron Boyer, Martha Hodapp, Klaus Misselt, Karl Stansberry, John Rieke, Marcia Earth and Planetary Astrophysics Solar and Stellar Astrophysics The launch of the James Webb Space Telescope (JWST) marks a pivotal moment for precise atmospheric characterization of Y dwarfs, the coldest brown dwarf spectral type. In this study, we leverage moderate spectral resolution observations (R $\sim$ 2700) with the G395H grating of the Near-Infrared Spectrograph (NIRSpec) onboard of JWST to characterize the nearby (9.9 pc) Y dwarf WISEPA J182831.08+265037.8 (WISE 1828). With the NIRSpec G395H 2.88-5.12 $\mathrmμ$m spectrum, we measure the abundances of CO, CO$_2$, CH$_4$, H$_2$S, NH$_3$, and H$_2$O, which are the major carbon, nitrogen, oxygen, and sulfur bearing species in the atmosphere. Based on the retrieved volume mixing ratios with the atmospheric retrieval framework CHIMERA, we report that the C/O ratio is $0.45 \pm 0.01$, close to the solar C/O value of 0.55, and the metallicity to be +0.30 $\pm$ 0.02 dex. Comparison between the retrieval results with the forward modeling results suggests that the model bias for C/O and metallicity could be as high as 0.03 and 0.97 dex respectively. We also report a lower limit of the $^{12}$CO/$^{13}$CO ratio of $>40 $, being consistent with the nominal solar value of 90. Our results highlight the potential of JWST in measuring the C/O ratios down to percent-level precision and characterizing isotopologues of cold planetary atmospheres similar to WISE 1828. |
| title | High-precision atmospheric characterization of a Y dwarf with JWST NIRSpec G395H spectroscopy: isotopologue, C/O ratio, metallicity, and the abundances of six molecular species |
| topic | Earth and Planetary Astrophysics Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2402.05900 |