The wind of W Hydrae as seen by Herschel

Context. Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, incl...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Astronomy and astrophysics (Berlin) 2014-01, Vol.561
Hauptverfasser: Khouri, T., de Koter, A., Decin, L., Waters, L. B. F. M., Lombaert, R., Royer, P., Swinyard, B., Barlow, M. J., Alcolea, J., Blommaert, J. A. D. L., Bujarrabal, V., Cernicharo, J., Groenewegen, M. A. T., Justtanont, K., Kerschbaum, F., Maercker, M., Marston, A., Matsuura, M., Melnick, G., Menten, K. M., Olofsson, H., Planesas, P., Polehampton, E., Posch, Th, Schmidt, M., Szczerba, R., Vandenbussche, B., Yates, J.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page
container_issue
container_start_page
container_title Astronomy and astrophysics (Berlin)
container_volume 561
creator Khouri, T.
de Koter, A.
Decin, L.
Waters, L. B. F. M.
Lombaert, R.
Royer, P.
Swinyard, B.
Barlow, M. J.
Alcolea, J.
Blommaert, J. A. D. L.
Bujarrabal, V.
Cernicharo, J.
Groenewegen, M. A. T.
Justtanont, K.
Kerschbaum, F.
Maercker, M.
Marston, A.
Matsuura, M.
Melnick, G.
Menten, K. M.
Olofsson, H.
Planesas, P.
Polehampton, E.
Posch, Th
Schmidt, M.
Szczerba, R.
Vandenbussche, B.
Yates, J.
description Context. Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, including the rate of mass loss and isotopic ratios. Aims. We characterize the CO emission from the wind of the low mass-loss rate oxygen-rich AGB star W Hya using data obtained by the HIFI, PACS, and SPIRE instruments on board the Herschel Space Observatory and ground-based telescopes. 12CO and 13CO lines are used to constrain the intrinsic 12C/13C ratio from resolved HIFI lines. Methods. We combined a state-of-the-art molecular line emission code and a dust continuum radiative transfer code to model the CO lines and the thermal dust continuum. Results. The acceleration of the outflow up to about 5.5 km s-1 is quite slow and can be represented by a β-type velocity law with index β = 5. Beyond this point, acceleration up the terminal velocity of 7 km s-1 is faster. Using the J = 10–9, 9–8, and 6–5 transitions, we find an intrinsic 12C/13C ratio of 18 ± 10 for W Hya, where the error bar is mostly due to uncertainties in the 12CO abundance and the stellar flux around 4.6 μm. To match the low-excitation CO lines, these molecules need to be photo-dissociated at ~500 stellar radii. The radial dust emission intensity profile of our stellar wind model matches PACS images at 70 μm out to 20′′ (or 800 stellar radii). For larger radii the observed emission is substantially stronger than our model predicts, indicating that at these locations there is extra material present. Conclusions. The initial slow acceleration of the wind may imply inefficient dust formation or dust driving in the lower part of the envelope. The final injection of momentum in the wind might be the result of an increase in the opacity thanks to the late condensation of dust species. The derived intrinsic isotopologue ratio for W Hya is consistent with values set by the first dredge-up and suggestive of an initial mass of 2 M⊙ or more. However, the uncertainty in the isotopologic ratio is large, which makes it difficult to set reliable limits on W Hya’s main-sequence mass.
doi_str_mv 10.1051/0004-6361/201322578
format Article
fullrecord <record><control><sourceid>istex</sourceid><recordid>TN_cdi_istex_primary_ark_67375_80W_1WVH05KL_S</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>ark_67375_80W_1WVH05KL_S</sourcerecordid><originalsourceid>FETCH-LOGICAL-c158t-a6dba2760522017abef805c4815ed005ba78d76015111e7d26e78d0ba01069683</originalsourceid><addsrcrecordid>eNo9jk9LxDAUxIMoWFc_gZechbjvJc0fj7KoFQseXO0xJM0rW11XaRa0N6_7Nf0kFhRPw8xvGIaxU4RzBI1zACiFUQbnElBJqa3bYwWWSgqwpdlnxX_jkB3l_DxZiU4V7Gy5Iv7RbxJ_63jz_bWrxjQE4iHzTLThceQVDbld0fqYHXRhnenkT2fs8fpquahEfX9zu7isRYvabUUwKQZpDWg5nbEhUudAt6VDTQlAx2BdmjBqRCSbpKEpgBgAwVwYp2ZM_O72eUuf_n3oX8Mw-jC8eGOV1d5B47F5qkDf1f5B_QBLZkVj</addsrcrecordid><sourcetype>Publisher</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype></control><display><type>article</type><title>The wind of W Hydrae as seen by Herschel</title><source>Bacon EDP Sciences France Licence nationale-ISTEX-PS-Journals-PFISTEX</source><source>Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals</source><source>EDP Sciences</source><creator>Khouri, T. ; de Koter, A. ; Decin, L. ; Waters, L. B. F. M. ; Lombaert, R. ; Royer, P. ; Swinyard, B. ; Barlow, M. J. ; Alcolea, J. ; Blommaert, J. A. D. L. ; Bujarrabal, V. ; Cernicharo, J. ; Groenewegen, M. A. T. ; Justtanont, K. ; Kerschbaum, F. ; Maercker, M. ; Marston, A. ; Matsuura, M. ; Melnick, G. ; Menten, K. M. ; Olofsson, H. ; Planesas, P. ; Polehampton, E. ; Posch, Th ; Schmidt, M. ; Szczerba, R. ; Vandenbussche, B. ; Yates, J.</creator><creatorcontrib>Khouri, T. ; de Koter, A. ; Decin, L. ; Waters, L. B. F. M. ; Lombaert, R. ; Royer, P. ; Swinyard, B. ; Barlow, M. J. ; Alcolea, J. ; Blommaert, J. A. D. L. ; Bujarrabal, V. ; Cernicharo, J. ; Groenewegen, M. A. T. ; Justtanont, K. ; Kerschbaum, F. ; Maercker, M. ; Marston, A. ; Matsuura, M. ; Melnick, G. ; Menten, K. M. ; Olofsson, H. ; Planesas, P. ; Polehampton, E. ; Posch, Th ; Schmidt, M. ; Szczerba, R. ; Vandenbussche, B. ; Yates, J.</creatorcontrib><description>Context. Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, including the rate of mass loss and isotopic ratios. Aims. We characterize the CO emission from the wind of the low mass-loss rate oxygen-rich AGB star W Hya using data obtained by the HIFI, PACS, and SPIRE instruments on board the Herschel Space Observatory and ground-based telescopes. 12CO and 13CO lines are used to constrain the intrinsic 12C/13C ratio from resolved HIFI lines. Methods. We combined a state-of-the-art molecular line emission code and a dust continuum radiative transfer code to model the CO lines and the thermal dust continuum. Results. The acceleration of the outflow up to about 5.5 km s-1 is quite slow and can be represented by a β-type velocity law with index β = 5. Beyond this point, acceleration up the terminal velocity of 7 km s-1 is faster. Using the J = 10–9, 9–8, and 6–5 transitions, we find an intrinsic 12C/13C ratio of 18 ± 10 for W Hya, where the error bar is mostly due to uncertainties in the 12CO abundance and the stellar flux around 4.6 μm. To match the low-excitation CO lines, these molecules need to be photo-dissociated at ~500 stellar radii. The radial dust emission intensity profile of our stellar wind model matches PACS images at 70 μm out to 20′′ (or 800 stellar radii). For larger radii the observed emission is substantially stronger than our model predicts, indicating that at these locations there is extra material present. Conclusions. The initial slow acceleration of the wind may imply inefficient dust formation or dust driving in the lower part of the envelope. The final injection of momentum in the wind might be the result of an increase in the opacity thanks to the late condensation of dust species. The derived intrinsic isotopologue ratio for W Hya is consistent with values set by the first dredge-up and suggestive of an initial mass of 2 M⊙ or more. However, the uncertainty in the isotopologic ratio is large, which makes it difficult to set reliable limits on W Hya’s main-sequence mass.</description><identifier>ISSN: 0004-6361</identifier><identifier>EISSN: 1432-0746</identifier><identifier>DOI: 10.1051/0004-6361/201322578</identifier><language>eng</language><publisher>EDP Sciences</publisher><subject>circumstellar matter ; line: formation ; radiative transfer ; stars: AGB and post-AGB ; stars: individual: W Hydrae ; stars: mass-loss</subject><ispartof>Astronomy and astrophysics (Berlin), 2014-01, Vol.561</ispartof><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c158t-a6dba2760522017abef805c4815ed005ba78d76015111e7d26e78d0ba01069683</citedby></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><link.rule.ids>314,777,781,27905,27906</link.rule.ids></links><search><creatorcontrib>Khouri, T.</creatorcontrib><creatorcontrib>de Koter, A.</creatorcontrib><creatorcontrib>Decin, L.</creatorcontrib><creatorcontrib>Waters, L. B. F. M.</creatorcontrib><creatorcontrib>Lombaert, R.</creatorcontrib><creatorcontrib>Royer, P.</creatorcontrib><creatorcontrib>Swinyard, B.</creatorcontrib><creatorcontrib>Barlow, M. J.</creatorcontrib><creatorcontrib>Alcolea, J.</creatorcontrib><creatorcontrib>Blommaert, J. A. D. L.</creatorcontrib><creatorcontrib>Bujarrabal, V.</creatorcontrib><creatorcontrib>Cernicharo, J.</creatorcontrib><creatorcontrib>Groenewegen, M. A. T.</creatorcontrib><creatorcontrib>Justtanont, K.</creatorcontrib><creatorcontrib>Kerschbaum, F.</creatorcontrib><creatorcontrib>Maercker, M.</creatorcontrib><creatorcontrib>Marston, A.</creatorcontrib><creatorcontrib>Matsuura, M.</creatorcontrib><creatorcontrib>Melnick, G.</creatorcontrib><creatorcontrib>Menten, K. M.</creatorcontrib><creatorcontrib>Olofsson, H.</creatorcontrib><creatorcontrib>Planesas, P.</creatorcontrib><creatorcontrib>Polehampton, E.</creatorcontrib><creatorcontrib>Posch, Th</creatorcontrib><creatorcontrib>Schmidt, M.</creatorcontrib><creatorcontrib>Szczerba, R.</creatorcontrib><creatorcontrib>Vandenbussche, B.</creatorcontrib><creatorcontrib>Yates, J.</creatorcontrib><title>The wind of W Hydrae as seen by Herschel</title><title>Astronomy and astrophysics (Berlin)</title><description>Context. Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, including the rate of mass loss and isotopic ratios. Aims. We characterize the CO emission from the wind of the low mass-loss rate oxygen-rich AGB star W Hya using data obtained by the HIFI, PACS, and SPIRE instruments on board the Herschel Space Observatory and ground-based telescopes. 12CO and 13CO lines are used to constrain the intrinsic 12C/13C ratio from resolved HIFI lines. Methods. We combined a state-of-the-art molecular line emission code and a dust continuum radiative transfer code to model the CO lines and the thermal dust continuum. Results. The acceleration of the outflow up to about 5.5 km s-1 is quite slow and can be represented by a β-type velocity law with index β = 5. Beyond this point, acceleration up the terminal velocity of 7 km s-1 is faster. Using the J = 10–9, 9–8, and 6–5 transitions, we find an intrinsic 12C/13C ratio of 18 ± 10 for W Hya, where the error bar is mostly due to uncertainties in the 12CO abundance and the stellar flux around 4.6 μm. To match the low-excitation CO lines, these molecules need to be photo-dissociated at ~500 stellar radii. The radial dust emission intensity profile of our stellar wind model matches PACS images at 70 μm out to 20′′ (or 800 stellar radii). For larger radii the observed emission is substantially stronger than our model predicts, indicating that at these locations there is extra material present. Conclusions. The initial slow acceleration of the wind may imply inefficient dust formation or dust driving in the lower part of the envelope. The final injection of momentum in the wind might be the result of an increase in the opacity thanks to the late condensation of dust species. The derived intrinsic isotopologue ratio for W Hya is consistent with values set by the first dredge-up and suggestive of an initial mass of 2 M⊙ or more. However, the uncertainty in the isotopologic ratio is large, which makes it difficult to set reliable limits on W Hya’s main-sequence mass.</description><subject>circumstellar matter</subject><subject>line: formation</subject><subject>radiative transfer</subject><subject>stars: AGB and post-AGB</subject><subject>stars: individual: W Hydrae</subject><subject>stars: mass-loss</subject><issn>0004-6361</issn><issn>1432-0746</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2014</creationdate><recordtype>article</recordtype><recordid>eNo9jk9LxDAUxIMoWFc_gZechbjvJc0fj7KoFQseXO0xJM0rW11XaRa0N6_7Nf0kFhRPw8xvGIaxU4RzBI1zACiFUQbnElBJqa3bYwWWSgqwpdlnxX_jkB3l_DxZiU4V7Gy5Iv7RbxJ_63jz_bWrxjQE4iHzTLThceQVDbld0fqYHXRhnenkT2fs8fpquahEfX9zu7isRYvabUUwKQZpDWg5nbEhUudAt6VDTQlAx2BdmjBqRCSbpKEpgBgAwVwYp2ZM_O72eUuf_n3oX8Mw-jC8eGOV1d5B47F5qkDf1f5B_QBLZkVj</recordid><startdate>201401</startdate><enddate>201401</enddate><creator>Khouri, T.</creator><creator>de Koter, A.</creator><creator>Decin, L.</creator><creator>Waters, L. B. F. M.</creator><creator>Lombaert, R.</creator><creator>Royer, P.</creator><creator>Swinyard, B.</creator><creator>Barlow, M. J.</creator><creator>Alcolea, J.</creator><creator>Blommaert, J. A. D. L.</creator><creator>Bujarrabal, V.</creator><creator>Cernicharo, J.</creator><creator>Groenewegen, M. A. T.</creator><creator>Justtanont, K.</creator><creator>Kerschbaum, F.</creator><creator>Maercker, M.</creator><creator>Marston, A.</creator><creator>Matsuura, M.</creator><creator>Melnick, G.</creator><creator>Menten, K. M.</creator><creator>Olofsson, H.</creator><creator>Planesas, P.</creator><creator>Polehampton, E.</creator><creator>Posch, Th</creator><creator>Schmidt, M.</creator><creator>Szczerba, R.</creator><creator>Vandenbussche, B.</creator><creator>Yates, J.</creator><general>EDP Sciences</general><scope>BSCLL</scope></search><sort><creationdate>201401</creationdate><title>The wind of W Hydrae as seen by Herschel</title><author>Khouri, T. ; de Koter, A. ; Decin, L. ; Waters, L. B. F. M. ; Lombaert, R. ; Royer, P. ; Swinyard, B. ; Barlow, M. J. ; Alcolea, J. ; Blommaert, J. A. D. L. ; Bujarrabal, V. ; Cernicharo, J. ; Groenewegen, M. A. T. ; Justtanont, K. ; Kerschbaum, F. ; Maercker, M. ; Marston, A. ; Matsuura, M. ; Melnick, G. ; Menten, K. M. ; Olofsson, H. ; Planesas, P. ; Polehampton, E. ; Posch, Th ; Schmidt, M. ; Szczerba, R. ; Vandenbussche, B. ; Yates, J.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c158t-a6dba2760522017abef805c4815ed005ba78d76015111e7d26e78d0ba01069683</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2014</creationdate><topic>circumstellar matter</topic><topic>line: formation</topic><topic>radiative transfer</topic><topic>stars: AGB and post-AGB</topic><topic>stars: individual: W Hydrae</topic><topic>stars: mass-loss</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Khouri, T.</creatorcontrib><creatorcontrib>de Koter, A.</creatorcontrib><creatorcontrib>Decin, L.</creatorcontrib><creatorcontrib>Waters, L. B. F. M.</creatorcontrib><creatorcontrib>Lombaert, R.</creatorcontrib><creatorcontrib>Royer, P.</creatorcontrib><creatorcontrib>Swinyard, B.</creatorcontrib><creatorcontrib>Barlow, M. J.</creatorcontrib><creatorcontrib>Alcolea, J.</creatorcontrib><creatorcontrib>Blommaert, J. A. D. L.</creatorcontrib><creatorcontrib>Bujarrabal, V.</creatorcontrib><creatorcontrib>Cernicharo, J.</creatorcontrib><creatorcontrib>Groenewegen, M. A. T.</creatorcontrib><creatorcontrib>Justtanont, K.</creatorcontrib><creatorcontrib>Kerschbaum, F.</creatorcontrib><creatorcontrib>Maercker, M.</creatorcontrib><creatorcontrib>Marston, A.</creatorcontrib><creatorcontrib>Matsuura, M.</creatorcontrib><creatorcontrib>Melnick, G.</creatorcontrib><creatorcontrib>Menten, K. M.</creatorcontrib><creatorcontrib>Olofsson, H.</creatorcontrib><creatorcontrib>Planesas, P.</creatorcontrib><creatorcontrib>Polehampton, E.</creatorcontrib><creatorcontrib>Posch, Th</creatorcontrib><creatorcontrib>Schmidt, M.</creatorcontrib><creatorcontrib>Szczerba, R.</creatorcontrib><creatorcontrib>Vandenbussche, B.</creatorcontrib><creatorcontrib>Yates, J.</creatorcontrib><collection>Istex</collection><jtitle>Astronomy and astrophysics (Berlin)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Khouri, T.</au><au>de Koter, A.</au><au>Decin, L.</au><au>Waters, L. B. F. M.</au><au>Lombaert, R.</au><au>Royer, P.</au><au>Swinyard, B.</au><au>Barlow, M. J.</au><au>Alcolea, J.</au><au>Blommaert, J. A. D. L.</au><au>Bujarrabal, V.</au><au>Cernicharo, J.</au><au>Groenewegen, M. A. T.</au><au>Justtanont, K.</au><au>Kerschbaum, F.</au><au>Maercker, M.</au><au>Marston, A.</au><au>Matsuura, M.</au><au>Melnick, G.</au><au>Menten, K. M.</au><au>Olofsson, H.</au><au>Planesas, P.</au><au>Polehampton, E.</au><au>Posch, Th</au><au>Schmidt, M.</au><au>Szczerba, R.</au><au>Vandenbussche, B.</au><au>Yates, J.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>The wind of W Hydrae as seen by Herschel</atitle><jtitle>Astronomy and astrophysics (Berlin)</jtitle><date>2014-01</date><risdate>2014</risdate><volume>561</volume><issn>0004-6361</issn><eissn>1432-0746</eissn><abstract>Context. Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, including the rate of mass loss and isotopic ratios. Aims. We characterize the CO emission from the wind of the low mass-loss rate oxygen-rich AGB star W Hya using data obtained by the HIFI, PACS, and SPIRE instruments on board the Herschel Space Observatory and ground-based telescopes. 12CO and 13CO lines are used to constrain the intrinsic 12C/13C ratio from resolved HIFI lines. Methods. We combined a state-of-the-art molecular line emission code and a dust continuum radiative transfer code to model the CO lines and the thermal dust continuum. Results. The acceleration of the outflow up to about 5.5 km s-1 is quite slow and can be represented by a β-type velocity law with index β = 5. Beyond this point, acceleration up the terminal velocity of 7 km s-1 is faster. Using the J = 10–9, 9–8, and 6–5 transitions, we find an intrinsic 12C/13C ratio of 18 ± 10 for W Hya, where the error bar is mostly due to uncertainties in the 12CO abundance and the stellar flux around 4.6 μm. To match the low-excitation CO lines, these molecules need to be photo-dissociated at ~500 stellar radii. The radial dust emission intensity profile of our stellar wind model matches PACS images at 70 μm out to 20′′ (or 800 stellar radii). For larger radii the observed emission is substantially stronger than our model predicts, indicating that at these locations there is extra material present. Conclusions. The initial slow acceleration of the wind may imply inefficient dust formation or dust driving in the lower part of the envelope. The final injection of momentum in the wind might be the result of an increase in the opacity thanks to the late condensation of dust species. The derived intrinsic isotopologue ratio for W Hya is consistent with values set by the first dredge-up and suggestive of an initial mass of 2 M⊙ or more. However, the uncertainty in the isotopologic ratio is large, which makes it difficult to set reliable limits on W Hya’s main-sequence mass.</abstract><pub>EDP Sciences</pub><doi>10.1051/0004-6361/201322578</doi></addata></record>
fulltext fulltext
identifier ISSN: 0004-6361
ispartof Astronomy and astrophysics (Berlin), 2014-01, Vol.561
issn 0004-6361
1432-0746
language eng
recordid cdi_istex_primary_ark_67375_80W_1WVH05KL_S
source Bacon EDP Sciences France Licence nationale-ISTEX-PS-Journals-PFISTEX; Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals; EDP Sciences
subjects circumstellar matter
line: formation
radiative transfer
stars: AGB and post-AGB
stars: individual: W Hydrae
stars: mass-loss
title The wind of W Hydrae as seen by Herschel
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-18T02%3A07%3A28IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-istex&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=The%20wind%20of%20W%E2%80%89Hydrae%20as%20seen%20by%20Herschel&rft.jtitle=Astronomy%20and%20astrophysics%20(Berlin)&rft.au=Khouri,%20T.&rft.date=2014-01&rft.volume=561&rft.issn=0004-6361&rft.eissn=1432-0746&rft_id=info:doi/10.1051/0004-6361/201322578&rft_dat=%3Cistex%3Eark_67375_80W_1WVH05KL_S%3C/istex%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_id=info:pmid/&rfr_iscdi=true