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An atlas of 2.4 to 4.1 μm ISO/SWS spectra of early-type stars

Lenorzer, A. and Vandenbussche, B. and Morris, P. and de Koter, A. and Geballe, T. R. and Waters, L. B. F. M. and Hony, S. and Kaper, L. (2002) An atlas of 2.4 to 4.1 μm ISO/SWS spectra of early-type stars. Astronomy & Astrophysics, 384 (2). pp. 473-490. ISSN 0004-6361.

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We present an atlas of spectra of O- and B-type stars, obtained with the Short Wavelength Spectrometer (SWS) during the Post-Helium program of the Infrared Space Observatory (ISO). This program is aimed at extending the Morgan & Keenan classification scheme into the near-infrared. Later type stars will be discussed in a separate publication. The observations consist of 57 SWS Post-Helium spectra from 2.4 to 4.1 µm, supplemented with 10 spectra acquired during the nominal mission with a similar observational setting. For B-type stars, this sample provides ample spectral coverage in terms of subtype and luminosity class. For O-type stars, the ISO sample is coarse and therefore is complemented with 8 UKIRT L’-band observations. In terms of the presence of diagnostic lines, the L’-band is likely the most promising of the near-infrared atmospheric windows for the study of the physical properties of B stars. Specifically, this wavelength interval contains the Brα, Pfγ, and other Pfund lines which are probes of spectral type, luminosity class and mass loss. Here, we present simple empirical methods based on the lines present in the 2.4 to 4.1 μm interval that allow the determination of i) the spectral type of B dwarfs and giants to within two subtypes; ii) the luminosity class of B stars to within two classes; iii) the mass-loss rate of O stars and B supergiants to within 0.25 dex.

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Additional Information:© 2002 ESO. Article published by EDP Sciences. Received 10 October 2001; Accepted 7 January 2002; Published online 15 March 2002. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA. We thank Jan Cami for stimulating discussions and help in data processing. This work was supported by NWO Pionier grant 600-78-333. AdK kindly acknowledges support from NWO Spinoza grant 08-0 to E. P. J. van den Heuvel. LK is supported by a fellowship of the Royal Academy of Sciences in The Netherlands. TRG is supported by the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., on behalf of the international Gemini partnership of Argentina, Australia, Brazil, Canada, Chile, the UK and the USA. We acknowledge the use of the Atomic Line List compiled by Peter van Hoof, which can be accessed through the web at
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Netherlands Organization for Scientific Research (NWO)600-78-333
Netherlands Organization for Scientific Research (NWO)08-0
Royal Academy of Sciences (The Netherlands)UNSPECIFIED
Gemini ObservatoryUNSPECIFIED
Subject Keywords:line: identification - atlases - stars: early-type - stars: fundamental parameters - infrared: stars
Issue or Number:2
Record Number:CaltechAUTHORS:20180307-082659342
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Official Citation:An atlas of 2.4 to 4.1 μm ISO/SWS spectra of early-type stars. A. Lenorzer, B. Vandenbussche, P. Morris, A. de Koter, T. R. Geballe, L. B. F. M. Waters, S. Hony and L. Kaper A&A, 384 2 (2002) 473-490. DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85164
Deposited By: Tony Diaz
Deposited On:07 Mar 2018 17:27
Last Modified:03 Oct 2019 19:27

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