On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars
The commonly accepted mechanism governing the formation of the nascent wind in oxygen-rich AGB stars combines an initial boost above the photosphere, given by shock waves resulting from stellar pulsations and convective cell partition, with a subsequent acceleration fuelled by the radiation pressure...
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Académie des sciences
2024-05-01
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| Series: | Comptes Rendus. Physique |
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| Online Access: | https://comptes-rendus.academie-sciences.fr/physique/articles/10.5802/crphys.185/ |
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| author | Darriulat, Pierre Hoai, Do Thi Nhung, Pham Thi Tuyet Diep, Pham Ngoc Ngoc, Nguyen Bich Thai, Tran Thi Anh, Pham Tuan |
| author_facet | Darriulat, Pierre Hoai, Do Thi Nhung, Pham Thi Tuyet Diep, Pham Ngoc Ngoc, Nguyen Bich Thai, Tran Thi Anh, Pham Tuan |
| author_sort | Darriulat, Pierre |
| collection | DOAJ |
| description | The commonly accepted mechanism governing the formation of the nascent wind in oxygen-rich AGB stars combines an initial boost above the photosphere, given by shock waves resulting from stellar pulsations and convective cell partition, with a subsequent acceleration fuelled by the radiation pressure of the star on dust grains. We use six nearby stars, for which detailed studies of visible and infrared observations at the VLT and millimetre observations at ALMA are available, to assess the extent to which the validity of this picture is currently corroborated. We show that while providing a very useful guide to current research and having received general support and suffered no contradiction, it still requires many additional observations to be reliably validated. In particular, observations of the highest possible angular resolution at both millimetre and visible/infrared wavelengths, performed in conjunction with measurements of the light curve, are necessary to tell apart the respective roles played by convection and stellar pulsations. The observed concurrence of high variability near the photosphere with persistence over decades, or even centuries, of the global anisotropy displayed by the CSE needs to be understood. New observations of the close neighbourhood of the star are required to elucidate the mechanism that governs rotation, in particular in the cases of R Dor, L2 Pup and EP Aqr. We argue that the presence of stellar or planetary companions does not seriously impact the formation of the nascent wind and only modifies its subsequent evolution. |
| format | Article |
| id | doaj-art-c9063f28744e44758be00deedabcc837 |
| institution | Kabale University |
| issn | 1878-1535 |
| language | English |
| publishDate | 2024-05-01 |
| publisher | Académie des sciences |
| record_format | Article |
| series | Comptes Rendus. Physique |
| spelling | doaj-art-c9063f28744e44758be00deedabcc8372025-02-07T13:53:46ZengAcadémie des sciencesComptes Rendus. Physique1878-15352024-05-0125G121925010.5802/crphys.18510.5802/crphys.185On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby starsDarriulat, Pierre0https://orcid.org/0000-0002-8979-6898Hoai, Do Thi1https://orcid.org/0000-0002-3816-4735Nhung, Pham Thi Tuyet2https://orcid.org/0000-0002-0311-0809Diep, Pham Ngoc3https://orcid.org/0000-0002-2808-0888Ngoc, Nguyen Bich4https://orcid.org/0000-0002-5913-5554Thai, Tran Thi5https://orcid.org/0000-0002-8408-4816Anh, Pham Tuan6https://orcid.org/0000-0002-3773-1435Department of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamDepartment of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet, Nghia Do, Cau Giay, Ha Noi, VietnamThe commonly accepted mechanism governing the formation of the nascent wind in oxygen-rich AGB stars combines an initial boost above the photosphere, given by shock waves resulting from stellar pulsations and convective cell partition, with a subsequent acceleration fuelled by the radiation pressure of the star on dust grains. We use six nearby stars, for which detailed studies of visible and infrared observations at the VLT and millimetre observations at ALMA are available, to assess the extent to which the validity of this picture is currently corroborated. We show that while providing a very useful guide to current research and having received general support and suffered no contradiction, it still requires many additional observations to be reliably validated. In particular, observations of the highest possible angular resolution at both millimetre and visible/infrared wavelengths, performed in conjunction with measurements of the light curve, are necessary to tell apart the respective roles played by convection and stellar pulsations. The observed concurrence of high variability near the photosphere with persistence over decades, or even centuries, of the global anisotropy displayed by the CSE needs to be understood. New observations of the close neighbourhood of the star are required to elucidate the mechanism that governs rotation, in particular in the cases of R Dor, L2 Pup and EP Aqr. We argue that the presence of stellar or planetary companions does not seriously impact the formation of the nascent wind and only modifies its subsequent evolution.https://comptes-rendus.academie-sciences.fr/physique/articles/10.5802/crphys.185/AGB starsCircumstellar envelopeRadio linesVisible/infrared emissionGas/dustPulsation/convection |
| spellingShingle | Darriulat, Pierre Hoai, Do Thi Nhung, Pham Thi Tuyet Diep, Pham Ngoc Ngoc, Nguyen Bich Thai, Tran Thi Anh, Pham Tuan On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars Comptes Rendus. Physique AGB stars Circumstellar envelope Radio lines Visible/infrared emission Gas/dust Pulsation/convection |
| title | On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars |
| title_full | On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars |
| title_fullStr | On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars |
| title_full_unstemmed | On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars |
| title_short | On the nascent wind of oxygen-rich AGB stars: scrutiny of a sample of nearby stars |
| title_sort | on the nascent wind of oxygen rich agb stars scrutiny of a sample of nearby stars |
| topic | AGB stars Circumstellar envelope Radio lines Visible/infrared emission Gas/dust Pulsation/convection |
| url | https://comptes-rendus.academie-sciences.fr/physique/articles/10.5802/crphys.185/ |
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