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Leavitt Variables: The Brightest Cepheids Variables and their Implications for the Distance Scale

Published online by Cambridge University Press:  12 April 2016

Gerald R. Grieve ,
Barry F. Madore  and
Douglas L. Welch
Gerald R. Grieve
Affiliation:
Canadian Centre for Remote Sensing, Ottawa, Ontario
Barry F. Madore
Affiliation:
Canadian Centre for Remote Sensing, Ottawa, Ontario
Douglas L. Welch
Affiliation:
Canadian Centre for Remote Sensing, Ottawa, Ontario

Abstract

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Two low-amplitude variable supergiants in the Large Magellanic Cloud, S65-08 and S65-48 are each found to have periods of approximately 250 days. The cfptical data suggest that these stars are high-luminosity cepheid variables falling more than one magnitude brighter than any other known Cepheids in the LMC. Confirmation of the cepheid nature of these stars comes from their H-band magnitudes which place them accurately on a simple linear extrapolation of the narrower infrared Period-Luminosity relation. So it appears that the cepheid Period-Luminosity relation extends up to Mv ~ -8.5. To honour the astronomer who discovered the first of these highest-liminosity Cepheids, we have sub-classified the variables with log P > 1.8 as being “Leavitt variables”. As soon as these long-period variables are discovered in other external galaxies, reliable distances should be possible out to (m-M) ~30.

Type
Part III. Extragalactic Cepheids and the PL Relation
Information
International Astronomical Union Colloquium , Volume 82: Cepheids: Theory and Observations , 1985 , pp. 215 - 218
Copyright
Copyright © Cambridge University Press 1985

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