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Zimmerman, B. A.

Publications and source records attributed to Zimmerman, B. A..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

A radial-velocity survey of the Hyades

Photoelectric radial-velocity measurements, obtained with external error as small as 0.1 km/s using the 200-inch Hale telescope at Palomar Observatory during the period 1971-1986, are reported for over 400 candidate members (with V magnitude between 6 and 14) of the Hyades cluster. The history of Hyades observations is recalled; the Palomar instrumentation and observing program are described; the data-reduction and standardization procedures are discussed in detail; and the data are presented in extensive tables and graphs. About 200 of the stars are classified as cluster members, including 60 spectroscopic binaries.

Griffin, R. F.↗
NASA NTRS1987

Approximate penetration factors for nuclear reactions of astrophysical interest

The ranges of validity of approximations of P(l), the penetration factor which appears in the parameterization of nuclear-reaction cross sections at low energies and is employed in the extrapolation of laboratory data to even lower energies of astrophysical interest, are investigated analytically. Consideration is given to the WKB approximation, P(l) at the energy of the total barrier, approximations derived from the asymptotic expansion of G(l) for large eta, approximations for small values of the parameter x, applications of P(l) to nuclear reactions, and the dependence of P(l) on channel radius. Numerical results are presented in tables and graphs, and parameter ranges where the danger of serious errors is high are identified.

Humblet, J.↗
NASA NTRS1985

Spectroscopic orbits for 16 more binaries in the Hyades field

A photoelectric survey of the radial velocities of Hyades candidates has provided data for 16 spectroscopic binary orbits, in addition to the 11 known binaries in the Hyades field. The majority of photoelectric observations in the survey were carried out at the Cambridge and Palomar Observatories using different data reduction techniques for determining radial velocities. It is found that two of the objects, vB 164 and J336, are definitely not members of the Hyades cluster; two other objects, HD 16909 and J301, appear to be located far from the center of the cluster, but still deserve classification as Hyades members. The gamma-velocity of HD 16909 differed slightly from the value expected for a member of the Hyades cluster. An additional twelve systems were definitely identified as members of the Hyades. The radial velocity values for all the candidate stars are given in a series of tables.

Griffin, R. F.↗