Results 141 to 150 of about 299,299 (345)

Li Evolution among Stars of Low/Intermediate Mass: the Metal-deficient Open Cluster NGC 2204

The Astronomical Journal
We have analyzed high-dispersion spectra in the Li 6708 Å region for 167 stars within the anticenter cluster NGC 2204. From 105 probable members, abundance analysis of 45 evolved stars produces [Fe/H] = −0.40 ± 0.12, [Si/Fe] = 0.14 ± 0.12, [Ca/Fe] = 0.29
Barbara J. Anthony-Twarog, Constantine P. Deliyannis, Aaron Steinhauer, Qinghui Sun, Bruce A. Twarog   +4 more
doaj   +1 more source

ON THE SURVIVAL OF BROWN DWARFS AND PLANETS ENGULFED BY THEIR GIANT HOST STAR [PDF]

, 2012
Jean-Claude Passy, Mordecai‐Mark Mac Low, Orsola De Marco   +2 more
openalex   +1 more source

Asteroseismology of Red Giant stars

, 2008
Sun-like oscillations, that is p-modes excited stochastically by convective noise, have now been observed in a number of Red Giant stars. Compared to those seen in the Sun, these modes are of large amplitude and long period, making the oscillations attractive prospects for observation.
Tarrant, N. J., Chaplin, W. J., Elsworth, Y. P., Spreckley, S. A., Stevens, I. R.   +4 more
openaire   +2 more sources

High‐Entropy Perovskite Nanofibers for Bifunctional Air Electrodes in Reversible Protonic Ceramic Electrochemical Cells

Advanced Functional Materials, EarlyView.
High‐entropy perovskite nanofibers serve as robust and active bifunctional air electrodes in reversible protonic ceramic electrochemical cells. Their compositional complexity stabilizes the lattice, enriches oxygen vacancies, and accelerates surface exchange.
Hyeonggeun Kim, Incheol Jeong, Seeun Oh, Dongyeon Kim, Kang Taek Lee   +4 more
wiley   +1 more source

A New Brown Dwarf Orbiting an M Star and an Investigation of the Eccentricity Distribution of Transiting Long-period Brown Dwarfs

The Astrophysical Journal Letters
The orbital eccentricities of brown dwarfs encode valuable information on their formation and evolution history, providing insights into whether they resemble giant planets or stellar binaries.
Tianjun Gan, Charles Cadieux, Shigeru Ida, Sharon X. Wang, Shude Mao, Zitao Lin, Keivan G. Stassun, Adam J. Burgasser, Steve B. Howell, Catherine A. Clark, Ivan A. Strakhov, Paul Benni, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Luc Arnold, Étienne Artigau, David Charbonneau, Karen A. Collins, Neil J. Cook, Zoë L. de Beurs, Sarah J. Deveny, John P. Doty, René Doyon, Colin Littlefield, Tyler Pritchard, Gabrielle Ross, Avi Shporer, Christopher R. Theissen, Benjamin M. Tofflemire, Andrew Vanderburg, David Watanabe   +34 more
doaj   +1 more source

An eccentric companion at the edge of the brown dwarf desert orbiting the 2.4M_⊙giant star HIP 67537 [PDF]

, 2017
M. I. Jones, Rafael Brahm, Robert A. Wittenmyer, H. Drass, J. S. Jenkins, C. Melo, J. Vos, P. Rojo   +7 more
openalex   +1 more source

Insight into the Internal Structure of Biogenic, Synthetic and Geological Apatite by Electron Microscopy and X‐Ray Scattering

Advanced Functional Materials, EarlyView.
Apatite occurs in many forms in nature, e.g. in teeth and geological minerals. Internally, biological apatite contains nanocrystals that are also found in synthetically prepared calcium phosphate nanoparticles which are used in biomedicine, e.g. for gene and drug delivery and for bone regeneration. Abstract Calcium phosphate is the inorganic component (
Kathrin Kostka, Oleg Prymak, Kateryna Loza, Matthias Epple   +3 more
wiley   +1 more source

FEAST: JWST/NIRCam View of the Resolved Stellar Populations of the Interacting Dwarf Galaxies NGC 4485 and NGC 4490

The Astrophysical Journal
We present new JWST/NIRCam observations of the interacting dwarf galaxy system NGC 4485–NGC 4490 (aka Arp 269), obtained as part of the Cycle 1 Feedback in Emerging Extragalactic Star Clusters (FEAST) program. NGC 4485 and NGC 4490 form the closest known
Giacomo Bortolini, Matteo Correnti, Angela Adamo, Michele Cignoni, Elena Sacchi, Monica Tosi, Göran Östlin, Anastasios Kapodistrias, Arjan Bik, Daniela Calzetti, Ana Duarte-Cabral, Flavia Dell’Agli, John S. Gallagher, Benjamin Gregg, Kathryn Grasha, Thomas S.-Y. Lai, Drew Lapeer, Sean T. Linden, Matteo Messa, Alex Pedrini, Elena Sabbi, Linda J. Smith, Helena Faustino Vieira, John M. Cannon, Salvador Duarte Puertas, Carmelle Robert   +25 more
doaj   +1 more source

Red Giant Stars in NGC 5128

, 2006
I present a selection of results obtained from VLT FORS1 and ISAAC photometric monitoring of late-type giants in NGC 5128 (=Centaurus A). The combination of optical and near-IR photometry allows to probe the full metallicity range of the stars on the upper red giant branch, thanks to combined low-metallicity sensitivity of the optical and high ...
openaire   +2 more sources

Why stars become red giants

The Astrophysical Journal, 1988
It is shown that a radiative envelope in which the Kramers opacity law holds cannot transport a luminosity larger than a critical value, and it is argued that the transition to red giant structure is triggered by the star's luminosity exceeding the critical value.
openaire   +1 more source