1115 Å far ultraviolet stellar photometry

Byram, E. T.; Chubb, T. A.; Werner, M. W.

doi:10.1017/s0074180900179598

Cited by 4 publications

(3 citation statements)

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“…Thus, the fact that the measured ultraviolet color indices for known f3 Cep stars scatter around. those for nonvariables of spectral type late o to early B (Byram, Chubb, and Werner 1965;Smith 1967;Bles,s, Code, and Houck 1968;Stecher 19(9) should, not be con .. sidered meaningful. Furthennore" Stecher points out that a (possible) ,ten percent error in the observed ultraviolet flux at A 2000 for a star of effective temperature 40,000° K implies an error in th,e effective temperature of 10,000° K.…”

Section: Far Ultraviolet Fluxesmentioning

confidence: 99%

Criteria for the Discovery of Beta Cephei Stars According to the Mu-Mechanism Theory

Stothers¹,

Simon²

1970

PASP

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Obselvational discriminants are proposed to test the p.-mechanism theory of f3 Cephei stars as advanced by Stothers and Simon (1969). These include: helium and nitrogen overabundances, far ultraviolet flux excesses (high surface temperature), narrow (occasionally broad) spectral line widths, and binary character. A list of potential f3 Cep candidates, comprising 24 spectroscopic binaries with spectral type 09-B4 III-V and a large orbital ratio of masses, has been compiled for the benefit of observers interested in searching for new f3 Cep stars. The data thus far accumulated are not in contradiction with, and occasionally positively support, the f1-mechanism theory.

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Section: Far Ultraviolet Fluxesmentioning

confidence: 99%

Criteria for the Discovery of Beta Cephei Stars According to the Mu-Mechanism Theory

Stothers¹,

Simon²

1970

PASP

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“…The most extensive comparison of model atmosphere calculations has been made in respect of photometric observations by Bless et al [21] who examined the UV data of a number of observers [22][23][24][25] which covered the range 1115 A-2800 A and included 35 main-sequence stars of spectral types B and A. The models were identified with the observations through the effective temperature scale of Morton and Adams [26].…”

Section: A Stellar Featuresmentioning

confidence: 99%

Observations of ultraviolet stellar spectra

Wilson¹

1970

Symp. - Int. Astron. Union

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The dividing line between photometry and spectrometry is not always obvious and for the purpose of this review, I will define ultraviolet stellar spectroscopy as observations with sufficient spectral resolution to allow the detection of individual spectral lines and their measurement in terms of wavelength and strength. From an examination of the existing observations this results in a resolution requirement of δλ < 10 Å. Since the best spectral resolution so far obtained is about 1 Å then this places the results to be discussed within the range 1–10 Å. In terms of λ/δλ this corresponds to a range of about 2000–200 and it is important to bear in mind that these represent low resolution spectra. In fact the limit of 200 that I have imposed would rarely be used for spectroscopic studies in ground based observatories where it corresponds, in the notation of the optical astronomer, to a dispersion of about 1000 Å/mm, the resolution limit being set by the photographic plate, typically taken as 20 μ. Hence, even the faintest objects like quasars are usually studied with a dispersion of a few hundred Å mm−1. The fact that such a resolution can be included here is an indication of the exceptionally strong resonance lines which occur in the ultraviolet and which can be detected with such a resolution. On the other hand, the richness of the ultraviolet spectrum is making and will continue to make, demands on improved resolution in order to separate the many features. The best achieved resolution of about 1 Å goes only part-way to solving this problem.

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“…The first ultraviolet astronomical observations were secured in a rocket flight during 1955 by Byram et al (1957) of N.R.L., which was followed by further observations by that group (Friedman, 1962;Chubb and Byram, 1963;Byram et al, 1964). The early observations were made with mechanical collimating devices feeding broad-band selective photomultipliers.…”

Section: A Unstabilised S O U N D I N G Rocketsmentioning

confidence: 99%

Ultraviolet Astronomy

Wilson¹

1968

Highlights astron.

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Ultraviolet astronomy is in a phase of very rapid development and any review of the new techniques involved is necessarily conditioned by the fact that most of the work is in a preparatory stage. This paper, therefore, will not be restricted to a discussion of those techniques which have undergone the ultimate test of their effectiveness, i.e., an actual space mission, but will include a consideration of those techniques which are still under development. Some omissions are therefore inevitable.The presentation is divided into three categories: (a) the vehicle and its stabilisation (if any), (b) the optics, and (c) detectors. Category (a) presents the major new technological problems and contributes the greater part of the total cost. Experience in the other categories of optics and detectors had, of course, reached an advanced and sophisticated level at the time of the advent of the rocket, but new and difficult problems have been posed mainly by their operation in a space environment, but also by their use in the ultraviolet region of the spectrum.

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1115 Å far ultraviolet stellar photometry

Cited by 4 publications

References 4 publications

Criteria for the Discovery of Beta Cephei Stars According to the Mu-Mechanism Theory

Criteria for the Discovery of Beta Cephei Stars According to the Mu-Mechanism Theory

Observations of ultraviolet stellar spectra

Ultraviolet Astronomy

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