Engineering topics

Brown, D. N.

Publications and source records attributed to Brown, D. N..

7 records

DOE OSTI2023

Workshop on a future muon program at FNAL

The Snowmass report on rare processes and precision measurements recommended Mu2e-II and a next generation muon facility at Fermilab (Advanced Muon Facility) as priorities for the frontier. The Workshop on a future muon program at FNAL was held in March 2023 to discuss design studies for Mu2e-II, organizing efforts for the next generation muon facility, and identify synergies with other efforts (e.g., muon collider). Topics included high-power targetry, status of R&D for Mu2e-II, development of compressor rings, FFA and concepts for muon experiments (conversion, decays, muonium and other opportunities) at AMF. This document summarizes the workshop discussions with a focus on future R&D tasks needed to realize these concepts.

43 PARTICLE ACCELERATORS↗

NASA NTRS1988

The galatic and LMC extreme line supergiants compared: IUE observations of the Henize-Carlson and Zoo star samples of massive supergiants

The Henize-Carlson sample of galactic massive supergiants, and a comparison between the Galactic and LMC samples are discussed. Several of the stars, notably He3-395 and S 127/LMC, have very similar shell characteristics. There appears to be little difference, other than luminosity, between the LMC and Galactic samples. One star, He3-1482, was detected with the Very Large Array at 6 cm. The UV data is combined with IRAS and optical information.

Shore, S. N.↗

NASA NTRS1988

The small scale structure of the interstellar medium in the Orion association: The flotsam of star formation

The small scale dynamics and structure of the interstellar medium of the Orion OB1b, c association was studied using IUE high dispersion SWP and LWR/LWP spectra. The area surveyed centers on the Belt and encompasses the Orion Cloak. The dynamics and abundances of the ionized and warm neutral gas surrounding the central parts of the association are determined using 35 B stars. Results are compared with the picture of the Orion interstellar medium gained using COPERNICUS, especially for the structure and dynamics of the Orion Cloak.

Sonneborn, G.↗

NASA NTRS1987

IUE observations of the broad continuum feature at 1400 A in the silicon and related stars

The upper main sequence chemically peculiar stars have previously been studied spectrophotometrically using low-resolution TD-1 spectra. These show that the broad continuum feature at 1400 A is a useful indicator of Si anomaly. In this paper the observations are extended to IUE low-resolution spectra and it is shown that this feature is indeed well correlated with Si and also with optical chemical peculiarity indices. Its utility in selecting silicon stars is further demonstrated. This feature is likely due to autoionization of Si II and is the best available discriminator of the overabundance of a key element in the Ap stars.

Shore, S. N.↗

NASA NTRS1987

The rapidly oscillating Ap stars as a test of stellar chromospheric heating mechanisms

The discovery of a new class of magnetic stars, the rapidly pulsating Ap stars, provides an unprecedented tool for the study of Alfvenic heating in the outer atmospheres of main sequence stars. In this note, it is noted that detection of rotationally-modulated chromospheric emission line fluxes, especially the Ca II, Mg II, and C IV lines, can provide a novel method for investigating the role of Alfvenic heating in stellar atmospheres.

Shore, S. N.↗

NASA NTRS1985

The magnetically controlled stellar wind of HD 21699

The discovery of a magnetically controlled stellar mass outflow in the helium-weak sn star HD 21699 = HR 1063 is reported. IUE observations show that the C IV resonance doublet is variable on the rotational time scale of about 2.5 days, and that there are no other observable spectrum variations in the UV. The magnetic field reverses sign on the rotational time scale. An interpretation of the observations in terms of magnetically structured jets is presented.

Brown, D. N.↗

NASA NTRS1982

Magnetospheres and winds of the helium strong stars: Dependence on rotation

Large aperture, low resolution spectra of 24 stars of types 05, 04, and 03 were obtained, and from these the energy distribution between 1200 and 3200 angstrom was derived in absolute units. The energies were combined with energies deduced from uvby and UBV photometry and corrected for interstellar extinction. Angular diameters and effective temperatures are also derived. The effective temperatures range from 24800K to 63000K. There is no correlation between effective temperature and spectral type or luminosity class for the early 0 stars. The size of the expected errors are also studied.

Barker, P. K.↗