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The orbit and companions of the classical Cepheid FF AqlNew radial velocities of the classical Cepheid FF Aql have been obtained and combined with previous observations to provide a revised orbit. A companion has been detected at 1800 A in IUE spectra with a spectral type of A9 V to F3 V. If the Cepheid has an evolutionary mass, then the mass ratio is M1/M2 = 3.8. A companion recently detected by speckle interferometry is in a longer-period orbit if it is a physical companion. In this case it is also an evolved star. The possible fourth member of the system, the visual companion, is unlikely to be a member of the system. The companion at 6 arcsec is unlikely to be a physical companion. Cepheids (in the 'free-fall' descending branch of the light curve) and nonvariable supergiants are shown to have a different spectral slope between 2900 and 1800 A for the same (B-V)0. IUE spectra of Polaris are rediscussed using other Cepheid spectra as comparison stars, and it is concluded that there is probably no sign of a companion.
Document ID
19900046771
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Evans, Nancy Remage
(York University North York, Canada; Computer Sciences Corp., Silver Spring, MD, United States)
Welch, Douglas L.
(McMaster University Hamilton, Canada)
Scarfe, Colin D.
(Victoria, University Canada)
Teays, Terry J.
(Computer Sciences Corp. Lanham, MD, United States)
Date Acquired
August 14, 2013
Publication Date
May 1, 1990
Publication Information
Publication: Astronomical Journal
Volume: 99
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
90A33826
Funding Number(s)
CONTRACT_GRANT: NAS5-28749
Distribution Limits
Public
Copyright
Other

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