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On the simultaneous optical and near-infrared variability of pre-main sequence stars

Eiroa, C. und Oudmaijer, R. D. und Davies, J. K. und de Winter, D. und Garzon, F. und Palacios, J. und Alberdi, A. und Ferlet, R. und Grady, C. A. und Cameron, A. und Deeg, H. J. und Harris, A. W. und Horne, K. und Merin, B. und Miranda, L. F. und Montesinos, B. und Mora, A. und Penny, A. und Quirrenbach, A. und Rauer, H. und Schneider, J. und Solano, E. und Tsapras, Y. und Wesselius, P. R. (2002) On the simultaneous optical and near-infrared variability of pre-main sequence stars. Astronomy and Astrophysics, 384, Seiten 1038-1049.

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Kurzfassung

For a complete understanding of the physical processes causing the photometric variability of pre-main sequence systems, simultaneous optical and near-IR observations are required to disentangle the emission from the stars and that from their associated circumstellar disks. Data of this sort are extremely rare and little systematic work has been reported to date. The work presented in this paper is a systematic attempt in this direction. It presents an analysis of the simultaneous optical and near-IR photometric variability of 18 Herbig Ae/Be and T Tauri stars which were observed in October 98 by the EXPORT collaboration. The time difference between the UBVRI and JHK measurements is less than 1 hour in 50% of the data and the largest difference is around 2 hours in only 10% of the data. Twelve stars appear to show a correlation between the optical and near-IR variability trends, which suggests a common physical origin such as spots and/or variable extinction. The optical and near-IR variability is uncorrelated in the rest of the objects, which suggests it originates in distinctly different regions. In general, the optical variability qualitatively follows the predictions of starspots or variable extinction. As far as the near-IR is concerned, the simultaneity of the observations demonstrates that for most objects the flux is largely produced by their circumstellar disks and, consequently, in many cases the near-IR fluctuations must be attributed to structural variations of such disks producing variations of their thermal emission and/or scattered light. The observed near-IR changes of up to around 1 mag on timescales of 1-2 days provide interesting challenges for understanding the mechanisms generating such remarkable variabilities, an issue insufficiently investigated until now but one which deserves further theoretical and modeling efforts.

Dokumentart:Zeitschriftenbeitrag
Zusätzliche Informationen: LIDO-Berichtsjahr=2001,
Titel:On the simultaneous optical and near-infrared variability of pre-main sequence stars
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Eiroa, C.Dpto. Física Teórica, C-XI, Facultad de Ciencieas, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
Oudmaijer, R. D.Department of Physics and Astronomy, University of Leeds, Leeds, UK
Davies, J. K.Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, UK
de Winter, D.TNO/TPD-Space Instrumentation, Delft, The Netherlands
Garzon, F.Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain
Palacios, J.Dpto. Física Teórica, C-XI, Facultad de Ciencieas, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
Alberdi, A.Instituto de Astrofísica de Andalucía, Granada, Spain
Ferlet, R.CNRS, Institut d'Astrophysique de Paris, Paris, France
Grady, C. A.NOAO/STIS, Goddard Space Flight Center, Greenbelt, MD, USA
Cameron, A.Physics & Astronomy, University of St. Andrews, St. Andrews, Scotland, UK
Deeg, H. J.Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain
Harris, A. W.NICHT SPEZIFIZIERT
Horne, K.Physics & Astronomy, University of St. Andrews, St. Andrews, Scotland, UK
Merin, B.L.A.E.F.F., VILSPA, Madrid, Spain
Miranda, L. F.Instituto de Astrofísica de Andalucía, Granada, Spain
Montesinos, B.L.A.E.F.F., VILSPA, Madrid, Spain
Mora, A.Dpto. Física Teórica, C-XI, Facultad de Ciencieas, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
Penny, A.Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK
Quirrenbach, A.Department of Physics, Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA, USA
Rauer, H.NICHT SPEZIFIZIERT
Schneider, J.Observatoire de Paris, Meudon, France
Solano, E.L.A.E.F.F., VILSPA, Madrid, Spain
Tsapras, Y.Physics & Astronomy, University of St. Andrews, St. Andrews, Scotland, UK
Wesselius, P. R.SRON Universiteitscomplex "Zernike", Groningen, The Netherlands
Datum:2002
Erschienen in:Astronomy and Astrophysics
Referierte Publikation:Ja
In ISI Web of Science:Ja
Band:384
Seitenbereich:Seiten 1038-1049
Status:veröffentlicht
Stichwörter:stars formation, stars pre-main sequence, stars variables general, stars circumstellar matter, accretion, accretion disks
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Weltraum (alt)
HGF - Programmthema:W EW - Erforschung des Weltraums
DLR - Schwerpunkt:Weltraum
DLR - Forschungsgebiet:W EW - Erforschung des Weltraums
DLR - Teilgebiet (Projekt, Vorhaben):NICHT SPEZIFIZIERT
Standort: Berlin-Adlershof
Institute & Einrichtungen:Institut für Weltraumsensorik und Planetenerkundung
Hinterlegt von: elib DLR-Beauftragter
Hinterlegt am:08 Dez 2005
Letzte Änderung:14 Jan 2010 18:57

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