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An Encoding System to Represent Stellar Spectral Classes in Archival Databases and Catalogs
Version 1.4

IVOA Working Draft 15 December 2011

Interest/Working Group:
Myron A. Smith, Randall Thompson, Richard O. Gray, Christopher Corbally, Inga Kamp
Myron A. Smith


An earlier version of this Working Draft was posted on the IVOA web site at, where a list of current IVOA Recommendations and other technical documents can also be found. This document was discussed for promotion at the IVOA Interoperability meeting in Baltimore in late October of 2008. The current version of the document has been reorganized to develop further the peculiarity codes for less commonly used spectral types and to address newly discovered details for this standard as well as practical matters of implementation in Appendices B and C. This Note is intended for discussion among the cognizant IVOA committees and has been presented formally to the IVOA semantics Committee for promotion at the October, 2008 IVOA Interoperabilty meeting in Baltimore. It is also intended for other data providers that have discovered the need for a spectral class nomenclature system in their own databases for spectroscopic missions. It has also been read and vetted by designated astronomers who are experts in the field of spectral classification and who have helped clarify how to best translate spectral types into a format useful for retrieval of information from stellar databases. The parsing code written to implement the nomenclature system, written in PHP, is available to other data providers upon request.

Status of this document

This is an IVOA Working Draft for review by IVOA members and other interested parties.
It is a draft document and may be updated, replaced, or obsoleted by other documents at any time.It is inappropriate to use IVOA Working Drafts as reference materials or to cite them as other than "work in progress".

Available formats: PDF, DOC

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