A Spectroastrometric Study of the Low-velocity Wind from DG Tau A
We obtained high-spectral resolution spectra (Δ v ∼ 2.5 km s ^−1 ) for DG Tau A from 4800 Å to 7500 Å using Subaru High Dispersion Spectrograph for the first time. The low-velocity components (LVCs, ∣ v ∣ < 100 km s ^−1 ) were observed in the [O I ] 5577, 6300, 6364 Å, [S II ] 6716, 6731 Å lines....
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adbbce |
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| author | Yu-Ru Chou Michihiro Takami Shin-Ping Lai Emma Whelan Noah B. Otten Min Fang Akito Tajitsu Masaaki Otsuka Hsien Shang Chun-Fan Liu Jennifer Karr Aisling Murphy |
| author_facet | Yu-Ru Chou Michihiro Takami Shin-Ping Lai Emma Whelan Noah B. Otten Min Fang Akito Tajitsu Masaaki Otsuka Hsien Shang Chun-Fan Liu Jennifer Karr Aisling Murphy |
| author_sort | Yu-Ru Chou |
| collection | DOAJ |
| description | We obtained high-spectral resolution spectra (Δ v ∼ 2.5 km s ^−1 ) for DG Tau A from 4800 Å to 7500 Å using Subaru High Dispersion Spectrograph for the first time. The low-velocity components (LVCs, ∣ v ∣ < 100 km s ^−1 ) were observed in the [O I ] 5577, 6300, 6364 Å, [S II ] 6716, 6731 Å lines. The offset position spectra observed in a component within the LVC velocity range between –16 km s ^−1 and –41 km s ^−1 , namely, LVC-M, show a “negative velocity gradient,” supporting the presence of a wide-angled wind. With 12–70 au wind lengths measured using spectroastrometry, we estimate a lower limit to the wind mass-loss rate of ∼10 ^−8 M _⊙ yr ^−1 . In addition to the LVCs, we identify two high-velocity components (HVCs, ∣ v ∣ > 100 km s ^−1 ) associated with the collimated jet in 26 lines ([N I ], [N II ], [O I ], [O II ], [O III ], [S II ], [Ca II ], [Fe II ], H α , H β , He I ). The one with a clear spatial offset from the star ( n _e ∼ 10 ^4 cm ^−3 , HVC1) is associated with an internal shock surface of the jet, while the other at the base ( n _e ∼ 10 ^6 cm ^−3 , HVC2) may be a stationary shock component. We find that the observed line profiles and the spatial scales of the LVC emission do not agree with the existing predictions for photoevaporative or magnetohydrodynamical disk winds. These could be explained by the X-wind model, but synthetic observations are required for detailed comparisons. |
| format | Article |
| id | doaj-art-a403d4e862874ac0bcfc74e352659f98 |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-a403d4e862874ac0bcfc74e352659f982025-08-20T03:06:51ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-019831610.3847/1538-4357/adbbceA Spectroastrometric Study of the Low-velocity Wind from DG Tau AYu-Ru Chou0https://orcid.org/0009-0004-9608-6132Michihiro Takami1https://orcid.org/0000-0001-9248-7546Shin-Ping Lai2https://orcid.org/0000-0001-5522-486XEmma Whelan3https://orcid.org/0000-0002-3741-9353Noah B. Otten4https://orcid.org/0000-0002-2530-4137Min Fang5https://orcid.org/0000-0001-8060-1321Akito Tajitsu6https://orcid.org/0000-0001-8813-9338Masaaki Otsuka7https://orcid.org/0000-0001-7076-0310Hsien Shang8https://orcid.org/0000-0001-8385-9838Chun-Fan Liu9https://orcid.org/0000-0002-1624-6545Jennifer Karr10https://orcid.org/0000-0003-3095-4772Aisling Murphy11https://orcid.org/0000-0003-0376-6127Institute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.C; Institute of Astronomy and Department of Physics, National Tsing Hua University , Hsinchu 30013, Taiwan, R.O.C; Max-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, GermanyInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.CInstitute of Astronomy and Department of Physics, National Tsing Hua University , Hsinchu 30013, Taiwan, R.O.CMaynooth University , Department of Physics, National University of Ireland Maynooth, Maynooth, Co. Kildare, IrelandMaynooth University , Department of Physics, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland; European Southern Observatory , Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, ChilePurple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China; University of Science and Technology of China , Hefei, People’s Republic of ChinaSubaru Telescope Okayama Branch Office , National Astronomical Observatory of Japan, 3037-5, Honjou, Kamogata, Asakuchi, Okayama 719-0232, JapanOkayama Observatory, Kyoto University , Kamogata, Asakuchi, Okayama 719-0232, JapanInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.CInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.CInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.CInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy-Mathematics Building, No.1, Sec. 4, Roosevelt Rd, Taipei 106319, Taiwan, R.O.CWe obtained high-spectral resolution spectra (Δ v ∼ 2.5 km s ^−1 ) for DG Tau A from 4800 Å to 7500 Å using Subaru High Dispersion Spectrograph for the first time. The low-velocity components (LVCs, ∣ v ∣ < 100 km s ^−1 ) were observed in the [O I ] 5577, 6300, 6364 Å, [S II ] 6716, 6731 Å lines. The offset position spectra observed in a component within the LVC velocity range between –16 km s ^−1 and –41 km s ^−1 , namely, LVC-M, show a “negative velocity gradient,” supporting the presence of a wide-angled wind. With 12–70 au wind lengths measured using spectroastrometry, we estimate a lower limit to the wind mass-loss rate of ∼10 ^−8 M _⊙ yr ^−1 . In addition to the LVCs, we identify two high-velocity components (HVCs, ∣ v ∣ > 100 km s ^−1 ) associated with the collimated jet in 26 lines ([N I ], [N II ], [O I ], [O II ], [O III ], [S II ], [Ca II ], [Fe II ], H α , H β , He I ). The one with a clear spatial offset from the star ( n _e ∼ 10 ^4 cm ^−3 , HVC1) is associated with an internal shock surface of the jet, while the other at the base ( n _e ∼ 10 ^6 cm ^−3 , HVC2) may be a stationary shock component. We find that the observed line profiles and the spatial scales of the LVC emission do not agree with the existing predictions for photoevaporative or magnetohydrodynamical disk winds. These could be explained by the X-wind model, but synthetic observations are required for detailed comparisons.https://doi.org/10.3847/1538-4357/adbbceStellar windsClassical T Tauri starsStellar jetsHigh resolution spectroscopy |
| spellingShingle | Yu-Ru Chou Michihiro Takami Shin-Ping Lai Emma Whelan Noah B. Otten Min Fang Akito Tajitsu Masaaki Otsuka Hsien Shang Chun-Fan Liu Jennifer Karr Aisling Murphy A Spectroastrometric Study of the Low-velocity Wind from DG Tau A The Astrophysical Journal Stellar winds Classical T Tauri stars Stellar jets High resolution spectroscopy |
| title | A Spectroastrometric Study of the Low-velocity Wind from DG Tau A |
| title_full | A Spectroastrometric Study of the Low-velocity Wind from DG Tau A |
| title_fullStr | A Spectroastrometric Study of the Low-velocity Wind from DG Tau A |
| title_full_unstemmed | A Spectroastrometric Study of the Low-velocity Wind from DG Tau A |
| title_short | A Spectroastrometric Study of the Low-velocity Wind from DG Tau A |
| title_sort | spectroastrometric study of the low velocity wind from dg tau a |
| topic | Stellar winds Classical T Tauri stars Stellar jets High resolution spectroscopy |
| url | https://doi.org/10.3847/1538-4357/adbbce |
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