San Francisco State University

About: San Francisco State University is a education organization based out in San Francisco, California, United States. It is known for research contribution in the topics: Population & Planet. The organization has 5669 authors who have published 11433 publications receiving 408075 citations. The organization is also known as: San Francisco State & San Francisco State Normal School.

Ten New and Updated Multiplanet Systems and a Survey of Exoplanetary Systems

Abstract: We present the latest velocities for ten multiplanet systems, including a re-analysis of archival Keck and Lick data, resulting in improved velocities that supersede our previously published measurements. We derive updated orbital fits for 10 Lick and Keck systems, including two systems (HD 11964, HD 183263) for which we provide confirmation of second planets only tentatively identified elsewhere, and two others (HD 187123 and HD 217107) for which we provide a major revision of the outer planet's orbit. We compile orbital elements from the literature to generate a catalog of the 28 published multiple-planet systems around stars within 200 pc. From this catalog we find several intriguing patterns emerging: (1) including those systems with long-term radial velocity trends, at least 28% of known planetary systems appear to contain multiple planets; (2) planets in multiple-planet systems have somewhat smaller eccentricities than single planets; and (3) the distribution of orbital distances of planets in multiplanet systems and single planets are inconsistent: single-planet systems show a pileup at P ~ 3 days and a jump near 1 AU, while multiplanet systems show a more uniform distribution in log-period. In addition, among all planetary systems we find the following. (1) There may be an emerging, positive correlation between stellar mass and giant-planet semimajor axis. (2) Exoplanets with M sin i > 1 M_(Jup) more massive than Jupiter have eccentricities broadly distributed across 0 < e < 0.5, while lower mass exoplanets exhibit a distribution peaked near e = 0.

The Lick Planet Search: Detectability and Mass Thresholds

Abstract: We present an analysis of 11 yr of precision radial velocity measurements of 76 nearby solar-type stars from the Lick radial velocity survey. For each star, we report on variability, periodicity, and long-term velocity trends. Our sample of stars contains eight known companions with mass less than 8 (M p sin i) Jupiter masses six of which were discovered at Lick. For the remaining stars, we place upper limits (M J ), on the companion mass as a function of orbital period. For most stars, we can exclude companions with velocity amplitude m s~1 at the 99% level, or for orbital radii K Z 20 M p sin i Z 0.7M J (a/AU)1@2 a ( 5 AU. We examine the implications of our results for the observed distribution of mass and orbital radius of companions. We show that the combination of intrinsic stellar variability and measurement errors most likely explains why all con—rmed companions so far have m s~1. The —nite duration of the K Z 40 observations limits detection of Jupiter-mass companions to AU. Thus it remains possible that the a ( 3 majority of solar-type stars harbor Jupiter-mass companions much like our own, and if so these com- panions should be detectable in a few years. It is striking that more massive companions with are rare at orbital radii 4¨6 AU; we could have detected such objects in D90% of stars, M p sin i ( 3M J yet found none. The observed companions show a ii piling-up ˇˇ toward small orbital radii, and there is a paucity of con—rmed and candidate companions with orbital radii between D0.2 and D1 AU. The small number of con—rmed companions means that we are not able to rule out selection eUects as the cause of these features. We show that the traditional method for detecting periodicities, the Lomb-Scargle perio- dogram, fails to account for statistical —uctuations in the mean of a sampled sinusoid, making it non- robust when the number of observations is small, the sampling is uneven, or for periods comparable to or greater than the duration of the observations. We adopt a ii —oating-mean ˇˇ periodogram, in which the zero point of the sinusoid is allowed to vary during the —t. We discuss in detail the normalization of the periodogram and the probability distribution of periodogram powers. We stress that the three diUer- ent prescriptions in the literature for normalizing the periodogram are statistically equivalent and that it is not possible to write a simple analytic form for the false alarm probability, making Monte Carlo methods essential. Subject headings: binaries: spectroscopicmethods: statisticalplanetary systems

Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog

Abstract: We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie Planet Search has obtained high-quality (R 70,000-90,000, S/N 300-500) echelle spectra of over 1000 nearby stars taken with the Hamilton spectrograph at Lick Observatory, the HIRES spectrograph at Keck, and UCLES at the Anglo Australian Observatory. A uniform analysis of the high-resolution spectra has yielded precise stellar parameters (Teff, log g, v sin i, [M/H], and individual elemental abundances for Fe, Ni, Si, Na, and Ti), enabling systematic error analyses and accurate theoretical stellar modeling. We have created a large database of theoretical stellar evolution tracks using the Yale Stellar Evolution Code (YREC) to match the observed parameters of the SPOCS stars. Our very dense grids of evolutionary tracks eliminate the need for interpolation between stellar evolutionary tracks and allow precise determinations of physical stellar parameters (mass, age, radius, size and mass of the convective zone, surface gravity, etc.). Combining our stellar models with the observed stellar atmospheric parameters and uncertainties, we compute the likelihood for each set of stellar model parameters separated by uniform time steps along the stellar evolutionary tracks. The computed likelihoods are used for a Bayesian analysis to derive posterior probability distribution functions for the physical stellar parameters of interest. We provide a catalog of physical parameters for 1074 stars that are based on a uniform set of high-quality spectral observations, a uniform spectral reduction procedure, and a uniform set of stellar evolutionary models. We explore this catalog for various possible correlations between stellar and planetary properties, which may help constrain the formation and dynamical histories of other planetary systems.

Motivating Employees in a New Governance Era: The Performance Paradigm Revisited

Abstract: What lessons does prior research on employee motivation off er public managers operating in — and researchers studying the dynamics of — a new governance era of resultsbased, downsized, networked, and customer-focused public organizations? 1 In this essay, we summarize what the voluminous body of social and behavioral science research tells us about motivating human performance in public, private, and nonprofi t organizations. Informing this analysis is a “ review of reviews ” of a sprawling research base that examines four elements of the traditional performance paradigm: employee incentives, job design, employee participation, and goal setting ( Locke et al. 1980 ). From this formidable body of research, we discern what is known about employee motivation, what is left to know, and how useful the classic performance paradigm is in light of these new governance challenges.

The relation of economic status to subjective well-being in developing countries: a meta-analysis.

Abstract: The current research synthesis integrates the findings of 111 independent samples from 54 economically developing countries that examined the relation between economic status and subjective well-being (SWB). The average economic status-SWB effect size was strongest among low-income developing economies (r = .28) and for samples that were least educated (r = .36). The relation was weakest among high-income developing economies (r = .10) and for highly educated samples (r = .13). Controlling for numerous covariates, the partial r effect size remained significant for the least-educated samples (pr = .18). Moderator analyses showed the economic status-SWB relation to be strongest when (a) economic status was defined as wealth (a stock variable), instead of as income (a flow variable), and (b) SWB was measured as life satisfaction (a cognitive assessment), instead of as happiness (an emotional assessment). Findings were replicated with a meta-analysis of the World Values Survey data. Discussion centers on the plausibility of need theory, alternative explanations of results, interpretation of moderators, and directions for future research.