Deep Search for Molecular Oxygen in TW Hya
The dominant form of oxygen in cold molecular clouds is gas-phase carbon monoxide (CO) and ice-phase water (H _2 O). Yet, in planet-forming disks around young stars, gas-phase CO and H _2 O are less abundant relative to their interstellar medium values, and no other major oxygen-carrying molecules h...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acf717 |
| _version_ | 1797658526129061888 |
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| author | Becky J. Williams L. Ilsedore Cleeves Christian Eistrup Jon P. Ramsey |
| author_facet | Becky J. Williams L. Ilsedore Cleeves Christian Eistrup Jon P. Ramsey |
| author_sort | Becky J. Williams |
| collection | DOAJ |
| description | The dominant form of oxygen in cold molecular clouds is gas-phase carbon monoxide (CO) and ice-phase water (H _2 O). Yet, in planet-forming disks around young stars, gas-phase CO and H _2 O are less abundant relative to their interstellar medium values, and no other major oxygen-carrying molecules have been detected. Some astrochemical models predict that gas-phase molecular oxygen (O _2 ) should be a major carrier of volatile oxygen in disks. We report a deep search for emission from the isotopologue ^16 O ^18 O ( N _J = 2 _1 − 0 _1 line at 233.946 GHz) in the nearby protoplanetary disk around TW Hya. We used imaging techniques and matched filtering to search for weak emission but do not detect ^16 O ^18 O. Based on our results, we calculate upper limits on the gas-phase O _2 abundance in TW Hya of (6.4–70) × 10 ^−7 relative to H, which is 2–3 orders of magnitude below solar oxygen abundance. We conclude that gas-phase O _2 is not a major oxygen carrier in TW Hya. Two other potential oxygen-carrying molecules, SO and SO _2 , were covered in our observations, which we also do not detect. Additionally, we report a serendipitous detection of the C ^15 N N _J = 2 _5/2 − 1 _3/2 hyperfine transitions, F = 3 − 2 and F = 2 − 1, at 219.9 GHz, which we found via matched filtering and confirm through imaging. |
| first_indexed | 2024-03-11T18:00:17Z |
| format | Article |
| id | doaj.art-a7413ac2b270429a9bacade610480ecf |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T18:00:17Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-a7413ac2b270429a9bacade610480ecf2023-10-17T08:56:26ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01956213510.3847/1538-4357/acf717Deep Search for Molecular Oxygen in TW HyaBecky J. Williams0https://orcid.org/0000-0002-1548-6811L. Ilsedore Cleeves1https://orcid.org/0000-0003-2076-8001Christian Eistrup2https://orcid.org/0000-0002-8743-1318Jon P. Ramsey3https://orcid.org/0000-0002-3835-3990Department of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; rjw9dmj@virginia.eduDepartment of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; rjw9dmj@virginia.eduDepartment of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; rjw9dmj@virginia.edu; Max Planck Institute for Astronomy , Königstuhl 17, D-69117 Heidelberg, GermanyDepartment of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; rjw9dmj@virginia.eduThe dominant form of oxygen in cold molecular clouds is gas-phase carbon monoxide (CO) and ice-phase water (H _2 O). Yet, in planet-forming disks around young stars, gas-phase CO and H _2 O are less abundant relative to their interstellar medium values, and no other major oxygen-carrying molecules have been detected. Some astrochemical models predict that gas-phase molecular oxygen (O _2 ) should be a major carrier of volatile oxygen in disks. We report a deep search for emission from the isotopologue ^16 O ^18 O ( N _J = 2 _1 − 0 _1 line at 233.946 GHz) in the nearby protoplanetary disk around TW Hya. We used imaging techniques and matched filtering to search for weak emission but do not detect ^16 O ^18 O. Based on our results, we calculate upper limits on the gas-phase O _2 abundance in TW Hya of (6.4–70) × 10 ^−7 relative to H, which is 2–3 orders of magnitude below solar oxygen abundance. We conclude that gas-phase O _2 is not a major oxygen carrier in TW Hya. Two other potential oxygen-carrying molecules, SO and SO _2 , were covered in our observations, which we also do not detect. Additionally, we report a serendipitous detection of the C ^15 N N _J = 2 _5/2 − 1 _3/2 hyperfine transitions, F = 3 − 2 and F = 2 − 1, at 219.9 GHz, which we found via matched filtering and confirm through imaging.https://doi.org/10.3847/1538-4357/acf717AstrochemistryProtoplanetary disks |
| spellingShingle | Becky J. Williams L. Ilsedore Cleeves Christian Eistrup Jon P. Ramsey Deep Search for Molecular Oxygen in TW Hya The Astrophysical Journal Astrochemistry Protoplanetary disks |
| title | Deep Search for Molecular Oxygen in TW Hya |
| title_full | Deep Search for Molecular Oxygen in TW Hya |
| title_fullStr | Deep Search for Molecular Oxygen in TW Hya |
| title_full_unstemmed | Deep Search for Molecular Oxygen in TW Hya |
| title_short | Deep Search for Molecular Oxygen in TW Hya |
| title_sort | deep search for molecular oxygen in tw hya |
| topic | Astrochemistry Protoplanetary disks |
| url | https://doi.org/10.3847/1538-4357/acf717 |
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