Planets have been reported orbiting the Sun-like stars 1 Cnc, Boo o, and And based on low-amplitude radial velocity variations. We have derived 1 Based on observations made at Mount Wilson Observatory, operated by the Mount Wilson Institute under an agreement with the Carnegie Institution of Washington. information on the rst two stars from analysis of… (More)
This paper discusses the use of web metrics tools at four digital libraries, the Instructional Architect, the Library of Congress, the National Science Digital Library, and WGBH Teachers' Domain. We describe some of the issues involved in using web metrics to report on ongoing web site performance. We also describe how web metrics can be used for focused… (More)
Radial velocity variations have revealed planets orbiting 51 Peg, 47 UMa, and 70 Vir, and a low-mass companion orbiting HD 114762. We analyze parallel records of photometric measurements in Stro mgren b and y and Johnson V , R, and I passbands and Ca II H and K Ñuxes in those stars. In the case of 51 Peg, the high precision of the di †erential photometric… (More)
We report preliminary lessons from a year of webmetrics research with two digital libraries. Despite the apparent 'plug-and-play-and-report' nature of webmetrics tools, much work was required to extract useful data from the tools used.
1. Introduction We deene pooled variance as the mean variance at some time scale, , within a longer term series, which is the combination of contributions from a variety of sources, some instrumental/statistical in origin, and others relating to astro-physical processes. (Dobson et al. 1990, 1995; Donahue et al. 1995). At a given time scale, the eeects from… (More)
We present results of the analysis of time-series photometry, Ca II H and K spectrophotometry and high-dispersion visible spectra of nine nearby Sun-like stars recently identiied as having planets. For the six stars whose presumed planets have orbital periods less than four months (Boo, 51 Peg, And, 1 Cnc, CrB, and 70 Vir), sine-curve ts to the photometric… (More)
Disk-integrated solar chromospheric Ca II K-line (3933.68 A) uxes have been measured almost daily at Sacramento Peak Observatory since 1977. Using observing windows selected to mimic seasonal windows for chromospheric measurements of lower main-sequence stars such as those observed by Mount Wilson Observatory's HK Project, we have measured the solar… (More)
Radial velocity variations have revealed planets orbiting 51 Peg, 47 UMa, and 70 Vir, and a low-mass companion orbiting HD 114762. We analyze parallel records of photometric measurements and Ca II H and K uxes in those stars. In the case of 51 Peg, the high precision of the diierential photometric measurements made by the 0.75m Automatic Photoelectric… (More)