The Sun and the Solar System Commons^™

How Much Has The Sun Influenced Northern Hemisphere Temperature Trends? An Ongoing Debate, Ronan Connolly, Willie Soon, Michael Connolly, Sallie Baliunas, Johan Berglund, C. John Butler, Rodolfo Gustavo Cionco, Ana G. Elias, Valery M. Fedorov, Hermann Harde, Gregory W. Henry, Douglas V. Hoyt, Ole Humlum, David R. Legates, Sebastian Lüning, Nicola Scafetta, Jan-Erik Solheim, László Szarka, Harry Van Loon, Víctor M. Velasco Herrera, Richard C. Willson, Hong Yan, Weijia Zhang

Information Systems and Engineering Management Research Publications

In order to evaluate how much Total Solar Irradiance (TSI) has influenced Northern Hemisphere surface air temperature trends, it is important to have reliable estimates of both quantities. Sixteen different estimates of the changes in TSI since at least the 19th century were compiled from the literature. Half of these estimates are "low variability" and half are "high variability". Meanwhile, five largely-independent methods for estimating Northern Hemisphere temperature trends were evaluated using: 1) only rural weather stations; 2) all available stations whether urban or rural (the standard approach); 3) only sea surface temperatures; 4) tree-ring widths as temperature proxies; 5) …

Sun-Like Stars Shed Light On Solar Climate Forcing, Philip G. Judge, Ricky Egeland, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Recently published precise stellar photometry of 72 Sun-like stars obtained at the Fairborn Observatory between 1993 and 2017 is used to set limits on the solar forcing of Earth's atmosphere of ±4.5 W m−2 since 1750. This compares with the +2.2 ± 1.1 W m−2 IPCC estimate for anthropogenic forcing. Three critical assumptions are made. In decreasing order of importance they are: (a) most of the brightness variations occur within the average time series length of ≈17 yr; (b) the Sun seen from the ecliptic behaves as an ensemble of middle-aged solar-like stars; and (c) narrowband photometry in the Strömgren …

Confronting A Solar Irradiance Reconstruction With Solar And Stellar Data, Philip G. Judge, G. Wesley Lockwood, Richard R. Radick, Gregory W. Henry, Alexander I. Shapiro, Werner Schmutz, Charles Lindsey

Information Systems and Engineering Management Research Publications

Context. A recent paper by Shapiro and colleagues (2011, A&A, 529, A67) reconstructs spectral and total irradiance variations of the Sun during the holocene.

Aims. In this note, we comment on why their methodology leads to large (0.5%) variations in the solar TSI on century-long time scales, in stark contrast to other reconstructions which have ≲ 0.1% variations.

Methods. We examine the amplitude of the irradiance variations from the point of view of both solar and stellar data.

Results. Shapiro et al.’s large amplitudes arise from differences between the irradiances computed from models A and C of Fontenla and colleagues, …

Chemical Abundances Of Red Giant Stars In The Globular Cluster M107 (Ngc 6171), Julia O'Connell, Christian I. Johnson, Catherine A. Pilachowski, Geoffrey Burks

Mathematical Sciences Faculty Research

We present chemical abundances of Al and several Fe-Peak and neutron-capture elements for 13 red giant branch stars in the Galactic globular cluster NGC 6171 (M107). The abundances were determined using equivalent width and spectrum synthesis analyses of moderate-resolution ( R ∼ 15,000), moderate signal-to-noise ratio (〈S/N〉 ∼ 80) spectra obtained with the WIYN telescope and Hydra multifiber spectrograph. A comparison between photometric and spectroscopic effective temperature estimates seems to indicate that a reddening value of E(B - V) = 0.46 may be more appropriate for this cluster than the more commonly used value of E(B - V) = 0.33. …