Results 71 to 80 of about 374,493 (293)

The Birth of a Galaxy: Primordial Metal Enrichment and Stellar Populations

, 2011
By definition, Population III stars are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas-phase, leading to large characteristic masses.
Abel, Barkana, Bertschinger, Bouwens, Bovill, Bovill, Bromm, Bryan, Cen, Clark, Clark, Ferrara, Frebel, Furlanetto, Glover, Gnedin, Greif, Greif, Greif, Greif, Górski, Heger, Heger, John H. Wise, Johnson, Karlsson, Kitayama, Kobayashi, Komatsu, Komiya, Krumholz, Machacek, Martin, Matthew J. Turk, Michael L. Norman, O'Shea, O'Shea, O'Shea, Omukai, Penprase, Razoumov, Ricotti, Safranek-Shrader, Scannapieco, Smith, Smith, Tan, Tom Abel, Trenti, Trenti, Truelove, Tumlinson, Tumlinson, Tumlinson, Turk, Whalen, Whalen, Wise, Wise, Wise, Yoshida, Yoshida, Yoshida   +62 more
core   +2 more sources

They might be giants: luminosity class, planet frequency, and planet-metallicity relation of the coolest Kepler target stars [PDF]

, 2012
We estimate the stellar parameters of late K and early M type Kepler target stars. We obtain medium resolution visible spectra of 382 stars with Kp-J>2 (~K5 and later spectral type).
Gaidos, Eric, Hilton, Eric, Lépine, Sébastien, Mann, Andrew W.   +3 more
core   +1 more source

Feasibility and Safety of High‐Dose Proton Re‐Irradiation in Recurrent Pediatric Central Nervous System Tumors: A Single‐Institution Retrospective Study

Pediatric Blood &Cancer, EarlyView.
ABSTRACT Purpose Pediatric central nervous system (CNS) tumors often recur despite multimodality therapy. Although re‐irradiation (re‐RT) has historically been limited by concerns for severe late toxicities, modern techniques have renewed interest in this approach. Proton therapy provides dosimetric advantages that may enable curative re‐treatment with
Jin‐Ho Song, Jonathan Baron, Carlos Chavez Perez, Sidharth Ramesh, Jane Minturn, Kavita A. Desai, Amish C. Shah, Jean M. Belasco, Kristina A. Cole, Michael J. Fisher, Phillip B. Storm, Peter M. Madsen, Goldie Kurtz, Robert A. Lustig, Christine Hill‐Kayser, Michael J. LaRiviere   +15 more
wiley   +1 more source

SIRIUS: Identifying Metal-poor Stars Enriched by a Single Supernova in a Dwarf Galaxy Cosmological Zoom-in Simulation Resolving Individual Massive Stars

The Astrophysical Journal Letters
Metal-poor stars enriched by a single supernova (mono-enriched stars) are direct proof (and provide valuable probes) of supernova nucleosynthesis. Photometric and spectroscopic observations have shown that metal-poor stars have a wide variety of chemical
Yutaka Hirai, Takayuki R. Saitoh, Michiko S. Fujii, Katsuhiro Kaneko, Timothy C. Beers   +4 more
doaj   +1 more source

Fossil Merger of a Population II Star

The Astrophysical Journal, 2018
Abstract We report on a fossil stellar merger for the subgiant primary of the visual binary HR 3750. The subgiant leads to an age τ ≃ 3.2 Gyr for a mass M A = 1.39 ± 0.09 M ⊙, in contradiction with its low iron-to-magnesium abundance that classifies it as a Population II (thick-disk) star.
Klaus Fuhrmann, Rolf Chini
openaire   +1 more source

The Formation Rates of Population III Stars and Chemical Enrichment of Halos during the Reionization Era

, 2009
[abridged] The First Stars in the Universe form out of pristine primordial gas clouds that have been radiatively cooled to a few hundreds of degrees Kelvin either via molecular or atomic (Lyman-Alpha) hydrogen lines.
Bromm, Cen, Ciardi, Clark, Couchman, Furlanetto, Furlanetto, Galli, Greif, Haiman, Haiman, Haiman, Heger, Heitmann, Hui, Kitayama, Kitayama, Komatsu ., Lukić, Lynden Bell, Machacek, Mackey, Massimo Stiavelli, Michele Trenti, Naoz, O'Shea, O'Shea, Oesch, Omukai, Omukai, Ostriker, Peebles, Peimbert, Ricotti, Scannapieco, Shull, Smith, Spergel, Stiavelli, Tegmark, Tornatore, Trenti, Trenti, Tumlinson, Tumlinson, Tumlinson, Venkatesan, Warren, Whalen, Whalen, Wise, Wise, Wyithe, Wyithe, Yoshida, Yoshida   +55 more
core   +1 more source

The Contribution of the First Stars to the Cosmic Infrared Background [PDF]

, 2001
We calculate the contribution to the cosmic infrared background from very massive metal-free stars at high redshift. We explore two plausible star-formation models and two limiting cases for the reprocessing of the ionizing stellar emission. We find that
Callaway, Callaway, M. Kamionkowski, M. R. Santos, V. Bromm   +4 more
core   +5 more sources

Efficacy and Safety Analysis of Roxarestat in Regulating Renal Anemia in Patients on Maintenance Hemodialysis

Therapeutic Apheresis and Dialysis, EarlyView.
ABSTRACT Objective To compare the efficacy and safety of roxarestat versus recombinant human erythropoietin (rhEPO) in the management of renal anemia in patients undergoing maintenance hemodialysis. Methods This was a prospective, open‐label, randomized controlled trial.
Lingling Chen, Junjie Zhu, Qiaonan Ge
wiley   +1 more source

How Population III Supernovae Determined the Properties of the First Galaxies

The Astrophysical Journal
Massive Population III stars can die as energetic supernovae that enrich the early Universe with metals and determine the properties of the first galaxies.
Ke-Jung Chen, Ching-Yao Tang, Daniel J. Whalen, Meng-Yuan Ho, Sung-Han Tsai, Po-Sheng Ou, Masaomi Ono   +6 more
doaj   +1 more source

The kinematics of Population II stars

The Astrophysical Journal, 1985
Simple dynamical models are made to study the implications of recent kinematic data for Population II stars in the Galactic halo. The models assume a scale-free distribution of stars orbiting within a spherical potential with a flat rotation curve. This potential is consistent with the observed properties of the globular cluster system.
openaire   +1 more source