Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A
Identifieur interne : 002070 ( PascalFrancis/Corpus ); précédent : 002069; suivant : 002071Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A
Auteurs : S. Vehoff ; C. A. Hummel ; J. D. Monnier ; P. Tuthill ; D. E. A. Nürnberger ; R. Siebenmorgen ; O. Chesneau ; W. J. DuschlSource :
- Astronomy and astrophysics : (Berlin. Print) [ 0004-6361 ] ; 2010.
Descripteurs français
- Pascal (Inist)
- Interférométrie IR, Objet stellaire jeune, Modèle géométrique, Etoile O, Etoile B, Observation interférométrique, Densité spectrale énergie, Distribution brillance, Transfert radiatif, Largeur équivalente, Multiplicité, Diamètre, Visibilité, Modèle sphérique, Matière circumstellaire, Etoile premier type, Formation stellaire.
English descriptors
- KwdEn :
- B stars, Brightness distribution, Circumstellar matter, Diameter, Early type stars, Equivalent width, Geometrical model, Infrared interferometry, Interferometric observation, Multiplicity, O stars, Radiative transfer, Spectral energy distribution, Spherical model, Star formation, Visibility, Young stellar object.
Abstract
Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims. Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods. Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results. The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions. While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution.
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Pour connaître la documentation sur le format Inist Standard.
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Format Inist (serveur)
| NO : | PASCAL 11-0061475 INIST |
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| ET : | Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A |
| AU : | VEHOFF (S.); HUMMEL (C. A.); MONNIER (J. D.); TUTHILL (P.); NÜRNBERGER (D. E. A.); SIEBENMORGEN (R.); CHESNEAU (O.); DUSCHL (W. J.) |
| AF : | Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2/69120 Heidelberg/Allemagne (1 aut.); European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001/Santiago/Chili (1 aut., 5 aut.); European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2/85748 Garching bei München/Allemagne (2 aut., 6 aut.); Department of Astronomy, University of Michigan/Ann Arbor, MI 48109/Etats-Unis (3 aut.); Sydney Institute for Astronomy, School of Physics, University of Sydney/NSW 2006/Australie (4 aut.); Observatoire de la Côte d'Azur, Dpt. Gemini-CNRS-UMR 6203, Avenue Copernic/06130 Grasse/France (7 aut.); Institut für Theoretische Physik und Astrophysik der Christian-Albrechts-Universität zu Kiel, Leibnizstr. 15/24118 Kiel/Allemagne (8 aut.); Steward Observatory, The University of Arizona, 933 N. Cherry Ave./Tucson, AZ 85721/Etats-Unis (8 aut.) |
| DT : | Publication en série; Niveau analytique |
| SO : | Astronomy and astrophysics : (Berlin. Print); ISSN 0004-6361; Coden AAEJAF; France; Da. 2010; Vol. 520; A78.1-A78.8; Bibl. 1/4 p. |
| LA : | Anglais |
| EA : | Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims. Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods. Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results. The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions. While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution. |
| CC : | 001E03 |
| FD : | Interférométrie IR; Objet stellaire jeune; Modèle géométrique; Etoile O; Etoile B; Observation interférométrique; Densité spectrale énergie; Distribution brillance; Transfert radiatif; Largeur équivalente; Multiplicité; Diamètre; Visibilité; Modèle sphérique; Matière circumstellaire; Etoile premier type; Formation stellaire |
| ED : | Infrared interferometry; Young stellar object; Geometrical model; O stars; B stars; Interferometric observation; Spectral energy distribution; Brightness distribution; Radiative transfer; Equivalent width; Multiplicity; Diameter; Visibility; Spherical model; Circumstellar matter; Early type stars; Star formation |
| SD : | Interferometría IR; Objeto estelar joven; Modelo geométrico; Observación interferométrica; Densidad espectral energía; Distribución brillantez; Anchura equivalente; Diámetro |
| LO : | INIST-14176.354000193504470880 |
| ID : | 11-0061475 |
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Vehoff</name><affiliation><inist:fA14 i1="01"><s1>Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2</s1><s2>69120 Heidelberg</s2><s3>DEU</s3><sZ>1 aut.</sZ></inist:fA14></affiliation><affiliation><inist:fA14 i1="02"><s1>European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001</s1><s2>Santiago</s2><s3>CHL</s3><sZ>1 aut.</sZ><sZ>5 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Hummel, C A" sort="Hummel, C A" uniqKey="Hummel C" first="C. A." last="Hummel">C. A. Hummel</name><affiliation><inist:fA14 i1="03"><s1>European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2</s1><s2>85748 Garching bei München</s2><s3>DEU</s3><sZ>2 aut.</sZ><sZ>6 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Monnier, J D" sort="Monnier, J D" uniqKey="Monnier J" first="J. D." last="Monnier">J. D. Monnier</name><affiliation><inist:fA14 i1="04"><s1>Department of Astronomy, University of Michigan</s1><s2>Ann Arbor, MI 48109</s2><s3>USA</s3><sZ>3 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Tuthill, P" sort="Tuthill, P" uniqKey="Tuthill P" first="P." last="Tuthill">P. Tuthill</name><affiliation><inist:fA14 i1="05"><s1>Sydney Institute for Astronomy, School of Physics, University of Sydney</s1><s2>NSW 2006</s2><s3>AUS</s3><sZ>4 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Nurnberger, D E A" sort="Nurnberger, D E A" uniqKey="Nurnberger D" first="D. E. A." last="Nürnberger">D. E. A. Nürnberger</name><affiliation><inist:fA14 i1="02"><s1>European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001</s1><s2>Santiago</s2><s3>CHL</s3><sZ>1 aut.</sZ><sZ>5 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Siebenmorgen, R" sort="Siebenmorgen, R" uniqKey="Siebenmorgen R" first="R." last="Siebenmorgen">R. Siebenmorgen</name><affiliation><inist:fA14 i1="03"><s1>European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2</s1><s2>85748 Garching bei München</s2><s3>DEU</s3><sZ>2 aut.</sZ><sZ>6 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Chesneau, O" sort="Chesneau, O" uniqKey="Chesneau O" first="O." last="Chesneau">O. Chesneau</name><affiliation><inist:fA14 i1="06"><s1>Observatoire de la Côte d'Azur, Dpt. Gemini-CNRS-UMR 6203, Avenue Copernic</s1><s2>06130 Grasse</s2><s3>FRA</s3><sZ>7 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Duschl, W J" sort="Duschl, W J" uniqKey="Duschl W" first="W. J." last="Duschl">W. J. Duschl</name><affiliation><inist:fA14 i1="07"><s1>Institut für Theoretische Physik und Astrophysik der Christian-Albrechts-Universität zu Kiel, Leibnizstr. 15</s1><s2>24118 Kiel</s2><s3>DEU</s3><sZ>8 aut.</sZ></inist:fA14></affiliation><affiliation><inist:fA14 i1="08"><s1>Steward Observatory, The University of Arizona, 933 N. Cherry Ave.</s1><s2>Tucson, AZ 85721</s2><s3>USA</s3><sZ>8 aut.</sZ></inist:fA14></affiliation></author></analytic><series><title level="j" type="main">Astronomy and astrophysics : (Berlin. Print)</title><title level="j" type="abbreviated">Astron. astrophys. : (Berl., Print)</title><idno type="ISSN">0004-6361</idno><imprint><date when="2010">2010</date></imprint></series></biblStruct></sourceDesc><seriesStmt><title level="j" type="main">Astronomy and astrophysics : (Berlin. Print)</title><title level="j" type="abbreviated">Astron. astrophys. : (Berl., Print)</title><idno type="ISSN">0004-6361</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>B stars</term><term>Brightness distribution</term><term>Circumstellar matter</term><term>Diameter</term><term>Early type stars</term><term>Equivalent width</term><term>Geometrical model</term><term>Infrared interferometry</term><term>Interferometric observation</term><term>Multiplicity</term><term>O stars</term><term>Radiative transfer</term><term>Spectral energy distribution</term><term>Spherical model</term><term>Star formation</term><term>Visibility</term><term>Young stellar object</term></keywords><keywords scheme="Pascal" xml:lang="fr"><term>Interférométrie IR</term><term>Objet stellaire jeune</term><term>Modèle géométrique</term><term>Etoile O</term><term>Etoile B</term><term>Observation interférométrique</term><term>Densité spectrale énergie</term><term>Distribution brillance</term><term>Transfert radiatif</term><term>Largeur équivalente</term><term>Multiplicité</term><term>Diamètre</term><term>Visibilité</term><term>Modèle sphérique</term><term>Matière circumstellaire</term><term>Etoile premier type</term><term>Formation stellaire</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims. Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods. Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results. The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions. While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution.</div></front></TEI><inist><standard h6="B"><pA><fA01 i1="01" i2="1"><s0>0004-6361</s0></fA01><fA02 i1="01"><s0>AAEJAF</s0></fA02><fA03 i2="1"><s0>Astron. astrophys. : (Berl., Print)</s0></fA03><fA05><s2>520</s2></fA05><fA08 i1="01" i2="1" l="ENG"><s1>Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A</s1></fA08><fA11 i1="01" i2="1"><s1>VEHOFF (S.)</s1></fA11><fA11 i1="02" i2="1"><s1>HUMMEL (C. A.)</s1></fA11><fA11 i1="03" i2="1"><s1>MONNIER (J. D.)</s1></fA11><fA11 i1="04" i2="1"><s1>TUTHILL (P.)</s1></fA11><fA11 i1="05" i2="1"><s1>NÜRNBERGER (D. E. A.)</s1></fA11><fA11 i1="06" i2="1"><s1>SIEBENMORGEN (R.)</s1></fA11><fA11 i1="07" i2="1"><s1>CHESNEAU (O.)</s1></fA11><fA11 i1="08" i2="1"><s1>DUSCHL (W. J.)</s1></fA11><fA14 i1="01"><s1>Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2</s1><s2>69120 Heidelberg</s2><s3>DEU</s3><sZ>1 aut.</sZ></fA14><fA14 i1="02"><s1>European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001</s1><s2>Santiago</s2><s3>CHL</s3><sZ>1 aut.</sZ><sZ>5 aut.</sZ></fA14><fA14 i1="03"><s1>European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2</s1><s2>85748 Garching bei München</s2><s3>DEU</s3><sZ>2 aut.</sZ><sZ>6 aut.</sZ></fA14><fA14 i1="04"><s1>Department of Astronomy, University of Michigan</s1><s2>Ann Arbor, MI 48109</s2><s3>USA</s3><sZ>3 aut.</sZ></fA14><fA14 i1="05"><s1>Sydney Institute for Astronomy, School of Physics, University of Sydney</s1><s2>NSW 2006</s2><s3>AUS</s3><sZ>4 aut.</sZ></fA14><fA14 i1="06"><s1>Observatoire de la Côte d'Azur, Dpt. Gemini-CNRS-UMR 6203, Avenue Copernic</s1><s2>06130 Grasse</s2><s3>FRA</s3><sZ>7 aut.</sZ></fA14><fA14 i1="07"><s1>Institut für Theoretische Physik und Astrophysik der Christian-Albrechts-Universität zu Kiel, Leibnizstr. 15</s1><s2>24118 Kiel</s2><s3>DEU</s3><sZ>8 aut.</sZ></fA14><fA14 i1="08"><s1>Steward Observatory, The University of Arizona, 933 N. Cherry Ave.</s1><s2>Tucson, AZ 85721</s2><s3>USA</s3><sZ>8 aut.</sZ></fA14><fA20><s2>A78.1-A78.8</s2></fA20><fA21><s1>2010</s1></fA21><fA23 i1="01"><s0>ENG</s0></fA23><fA43 i1="01"><s1>INIST</s1><s2>14176</s2><s5>354000193504470880</s5></fA43><fA44><s0>0000</s0><s1>© 2011 INIST-CNRS. All rights reserved.</s1></fA44><fA45><s0>1/4 p.</s0></fA45><fA47 i1="01" i2="1"><s0>11-0061475</s0></fA47><fA60><s1>P</s1></fA60><fA61><s0>A</s0></fA61><fA64 i1="01" i2="1"><s0>Astronomy and astrophysics : (Berlin. Print)</s0></fA64><fA66 i1="01"><s0>FRA</s0></fA66><fC01 i1="01" l="ENG"><s0>Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims. Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods. Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results. The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions. While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution.</s0></fC01><fC02 i1="01" i2="3"><s0>001E03</s0></fC02><fC03 i1="01" i2="X" l="FRE"><s0>Interférométrie IR</s0><s5>26</s5></fC03><fC03 i1="01" i2="X" l="ENG"><s0>Infrared interferometry</s0><s5>26</s5></fC03><fC03 i1="01" i2="X" l="SPA"><s0>Interferometría IR</s0><s5>26</s5></fC03><fC03 i1="02" i2="X" l="FRE"><s0>Objet stellaire jeune</s0><s2>NO</s2><s5>27</s5></fC03><fC03 i1="02" i2="X" l="ENG"><s0>Young stellar object</s0><s2>NO</s2><s5>27</s5></fC03><fC03 i1="02" i2="X" l="SPA"><s0>Objeto estelar joven</s0><s2>NO</s2><s5>27</s5></fC03><fC03 i1="03" i2="X" l="FRE"><s0>Modèle géométrique</s0><s5>28</s5></fC03><fC03 i1="03" i2="X" l="ENG"><s0>Geometrical model</s0><s5>28</s5></fC03><fC03 i1="03" i2="X" l="SPA"><s0>Modelo geométrico</s0><s5>28</s5></fC03><fC03 i1="04" i2="3" l="FRE"><s0>Etoile O</s0><s5>29</s5></fC03><fC03 i1="04" i2="3" l="ENG"><s0>O stars</s0><s5>29</s5></fC03><fC03 i1="05" i2="3" l="FRE"><s0>Etoile B</s0><s5>30</s5></fC03><fC03 i1="05" i2="3" l="ENG"><s0>B stars</s0><s5>30</s5></fC03><fC03 i1="06" i2="X" l="FRE"><s0>Observation interférométrique</s0><s5>31</s5></fC03><fC03 i1="06" i2="X" l="ENG"><s0>Interferometric observation</s0><s5>31</s5></fC03><fC03 i1="06" i2="X" l="SPA"><s0>Observación interferométrica</s0><s5>31</s5></fC03><fC03 i1="07" i2="X" l="FRE"><s0>Densité spectrale énergie</s0><s5>32</s5></fC03><fC03 i1="07" i2="X" l="ENG"><s0>Spectral energy distribution</s0><s5>32</s5></fC03><fC03 i1="07" i2="X" l="SPA"><s0>Densidad espectral energía</s0><s5>32</s5></fC03><fC03 i1="08" i2="X" l="FRE"><s0>Distribution brillance</s0><s5>33</s5></fC03><fC03 i1="08" i2="X" l="ENG"><s0>Brightness distribution</s0><s5>33</s5></fC03><fC03 i1="08" i2="X" l="SPA"><s0>Distribución brillantez</s0><s5>33</s5></fC03><fC03 i1="09" i2="3" l="FRE"><s0>Transfert radiatif</s0><s5>34</s5></fC03><fC03 i1="09" i2="3" l="ENG"><s0>Radiative transfer</s0><s5>34</s5></fC03><fC03 i1="10" i2="X" l="FRE"><s0>Largeur équivalente</s0><s5>35</s5></fC03><fC03 i1="10" i2="X" l="ENG"><s0>Equivalent width</s0><s5>35</s5></fC03><fC03 i1="10" i2="X" l="SPA"><s0>Anchura equivalente</s0><s5>35</s5></fC03><fC03 i1="11" i2="3" l="FRE"><s0>Multiplicité</s0><s5>36</s5></fC03><fC03 i1="11" i2="3" l="ENG"><s0>Multiplicity</s0><s5>36</s5></fC03><fC03 i1="12" i2="X" l="FRE"><s0>Diamètre</s0><s5>37</s5></fC03><fC03 i1="12" i2="X" l="ENG"><s0>Diameter</s0><s5>37</s5></fC03><fC03 i1="12" i2="X" l="SPA"><s0>Diámetro</s0><s5>37</s5></fC03><fC03 i1="13" i2="3" l="FRE"><s0>Visibilité</s0><s5>38</s5></fC03><fC03 i1="13" i2="3" l="ENG"><s0>Visibility</s0><s5>38</s5></fC03><fC03 i1="14" i2="3" l="FRE"><s0>Modèle sphérique</s0><s5>39</s5></fC03><fC03 i1="14" i2="3" l="ENG"><s0>Spherical model</s0><s5>39</s5></fC03><fC03 i1="15" i2="3" l="FRE"><s0>Matière circumstellaire</s0><s5>40</s5></fC03><fC03 i1="15" i2="3" l="ENG"><s0>Circumstellar matter</s0><s5>40</s5></fC03><fC03 i1="16" i2="3" l="FRE"><s0>Etoile premier type</s0><s5>41</s5></fC03><fC03 i1="16" i2="3" l="ENG"><s0>Early type stars</s0><s5>41</s5></fC03><fC03 i1="17" i2="3" l="FRE"><s0>Formation stellaire</s0><s5>42</s5></fC03><fC03 i1="17" i2="3" l="ENG"><s0>Star formation</s0><s5>42</s5></fC03><fN21><s1>038</s1></fN21><fN44 i1="01"><s1>OTO</s1></fN44><fN82><s1>OTO</s1></fN82></pA></standard><server><NO>PASCAL 11-0061475 INIST</NO><ET>Mid-infrared interferometry of the massive young stellar object NGC 3603 - IRS 9A</ET><AU>VEHOFF (S.); HUMMEL (C. A.); MONNIER (J. D.); TUTHILL (P.); NÜRNBERGER (D. E. A.); SIEBENMORGEN (R.); CHESNEAU (O.); DUSCHL (W. J.)</AU><AF>Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2/69120 Heidelberg/Allemagne (1 aut.); European Organisation for Astronomical Research in the Southern Hemisphere, Casilla 19001/Santiago/Chili (1 aut., 5 aut.); European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2/85748 Garching bei München/Allemagne (2 aut., 6 aut.); Department of Astronomy, University of Michigan/Ann Arbor, MI 48109/Etats-Unis (3 aut.); Sydney Institute for Astronomy, School of Physics, University of Sydney/NSW 2006/Australie (4 aut.); Observatoire de la Côte d'Azur, Dpt. Gemini-CNRS-UMR 6203, Avenue Copernic/06130 Grasse/France (7 aut.); Institut für Theoretische Physik und Astrophysik der Christian-Albrechts-Universität zu Kiel, Leibnizstr. 15/24118 Kiel/Allemagne (8 aut.); Steward Observatory, The University of Arizona, 933 N. Cherry Ave./Tucson, AZ 85721/Etats-Unis (8 aut.)</AF><DT>Publication en série; Niveau analytique</DT><SO>Astronomy and astrophysics : (Berlin. Print); ISSN 0004-6361; Coden AAEJAF; France; Da. 2010; Vol. 520; A78.1-A78.8; Bibl. 1/4 p.</SO><LA>Anglais</LA><EA>Context. Very few massive young stellar objects (MYSO) have been studied in the infrared at high angular resolution due to their rarity and large associated extinction. We present observations and models for one of these MYSO candidates, NGC 3603 IRS 9A. Aims. Our goal is to investigate with infrared interferometry the structure of IRS 9A on scales as small as 200 AU, exploiting the fact that a cluster of O and B stars has blown away much of the obscuring foreground dust and gas. Methods. Observations in the N-band were carried out with the MIDI beam combiner attached to the VLTI, providing spatial information on scales of about 25-95 milli-arcsec (mas). Additional interferometric observations which probe the structure of IRS 9A on larger scales were performed with an aperture mask installed in the T-ReCS instrument of Gemini South. The spectral energy distribution (SED) is constrained by the MIDI N-band spectrum and by data from the Spitzer Space Telescope. Our efforts to model the structure and SED of IRS 9A range from simple geometrical models of the brightness distribution to one- and two-dimensional radiative transfer computations. Results. The target is resolved by T-ReCS, with an equivalent (elliptical) Gaussian width of 330 mas by 280 mas (2300 AU by 2000 AU). Despite this fact, a warm compact unresolved component was detected by MIDI which is possibly associated with the inner regions of a flattened dust distribution. Based on our interferometric data, no sign of multiplicity was found on scales between about 200 AU and 700 AU projected separation. A geometric model consisting of a warm (1000 K) ring (400 AU diameter) and a cool (140 K) large envelope provides a good fit to the data. No single model fitting all visibility and photometric data could be found, with disk models performing better than spherical models. Conclusions. While the data are clearly inconsistent with a spherical dust distribution they are insufficient to prove the existence of a disk but rather hint at a more complex dust distribution.</EA><CC>001E03</CC><FD>Interférométrie IR; Objet stellaire jeune; Modèle géométrique; Etoile O; Etoile B; Observation interférométrique; Densité spectrale énergie; Distribution brillance; Transfert radiatif; Largeur équivalente; Multiplicité; Diamètre; Visibilité; Modèle sphérique; Matière circumstellaire; Etoile premier type; Formation stellaire</FD><ED>Infrared interferometry; Young stellar object; Geometrical model; O stars; B stars; Interferometric observation; Spectral energy distribution; Brightness distribution; Radiative transfer; Equivalent width; Multiplicity; Diameter; Visibility; Spherical model; Circumstellar matter; Early type stars; Star formation</ED><SD>Interferometría IR; Objeto estelar joven; Modelo geométrico; Observación interferométrica; Densidad espectral energía; Distribución brillantez; Anchura equivalente; Diámetro</SD><LO>INIST-14176.354000193504470880</LO><ID>11-0061475</ID></server></inist></record>Pour manipuler ce document sous Unix (Dilib)
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