Results 1 to 10 of about 601,537 (357)

Cavitation pressure in liquid helium [PDF]

Phys. Rev. B 64 (2001), 064507, 2001
Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk ...
B. M. Abraham, B. M. Abraham, C. E. Campbell, D. M. Jezek, F. Caupin, F. Caupin, F. Caupin, F. Dalfovo, G. H. Bauer, G. W. Waters, H. J. Maris, H. J. Maris, H. Lambaré, J. A. Nissen, J. Boronat, J. C. Wheatley, J. Casulleras, J. Wilks, K. Dransfeld, Lord Rayleigh, M. A. Solis, M. Guilleumas, M. Guilleumas, M. Kollar, M. P. Bertinat, P. Roche, S. Balibar, S. Balibar, S. Balibar, S. N. Burmistrov, W. H. Press, X. Chavanne   +31 more
arxiv   +6 more sources

Helium and Multiple Populations in the Massive Globular Cluster NGC6266 (M62) [PDF]

, 2014
Recent studies suggest that the helium content of multiple stellar populations in globular clusters (GCs) is not uniform. The range of helium varies from cluster to cluster with more massive GCs having, preferentially, large helium spread. GCs with large helium variations also show extended-blue horizontal branch (HB).
Milone, A. P.
arxiv   +4 more sources

Helium Absorption at 1083 nm from Extended Exoplanet Atmospheres: Dependence on Stellar Radiation [PDF]

ApJ, 881, 133 (2019), 2019
Strong absorption signatures in the helium line at 1083 nm have recently been detected in transmission spectra of several close-in exoplanets. This absorption line originates from neutral helium atoms in an excited, metastable 2$^3$S state. The population of helium atoms in this excited state is governed by the spectral shape and intensity of the ...
A. Oklopčić
arxiv   +3 more sources

Carbon Shell or Core Ignitions in White Dwarfs Accreting from Helium Stars [PDF]

, 2016
White dwarfs accreting from helium stars can stably burn at the accreted rate and avoid the challenge of mass loss associated with unstable Helium burning that is a concern for many Type Ia supernovae scenarios. We study binaries with helium stars of mass $1.25 M_\odot\le M_{\rm{He}} \le 1.8 M_\odot$, which have lost their hydrogen rich envelopes in an
Bildsten, Lars, Brooks, Jared, Paxton, Bill, Schwab, Josiah   +3 more
arxiv   +3 more sources

The Hottest Horizontal-Branch Stars in omega Centauri - Late Hot Flasher vs. Helium Enrichment [PDF]

, 2007
UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either as results of the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the
Bono, G., Calamida, A., Dreizler, S., Lanz, T., Moehler, S., Monelli, M., Nonino, M., Sweigart, A. V.   +7 more
arxiv   +4 more sources

Can R CrB stars form from the merger of two helium white dwarfs? [PDF]

, 2012
Due to orbital decay by gravitational-wave radiation, some close-binary helium white dwarfs are expected to merge within a Hubble time. The immediate merger products are believed to be helium-rich sdO stars, essentially helium main-sequence stars. We present new evolution calculations for these post-merger stars beyond the core helium-burning phase ...
Benz, Brown, C. Simon Jeffery, Clayton, Clayton, Cropper, Dinger, Evans, Guerrero, Han, Iben, Jeffery, Jeffery, Kilic, Kilic, Longland, Longland, Lorén-Aguilar, Nelemans, Nelemans, Paczyński, Pakmor, Pandey, Pandey, Paxton, Rebassa-Mansergas, Saio, Saio, Trimble, Warner, Webbink, Weiss, Xianfei Zhang, Yoon, Zhang   +34 more
arxiv   +3 more sources

Review of Membranes for Helium Separation and Purification

Membranes, 2017
Membrane gas separation has potential for the recovery and purification of helium, because the majority of membranes have selectivity for helium. This review reports on the current state of the research and patent literature for membranes undertaking ...
Colin A. Scholes, Ujjal K. Ghosh
doaj   +2 more sources

Helium Ionization in the Diffuse Ionized Gas surrounding UCHII regions [PDF]

, 2017
We present measurements of the singly ionized helium to hydrogen ratio ($n_{He^+}/n_{H^+}$) toward diffuse gas surrounding three Ultra-Compact HII (UCHII ) regions: G10.15-0.34, G23.46-0.20 \& G29.96-0.02. We observe radio recombination lines (RRLs) of hydrogen and helium near 5 GHz using the GBT to measure the $n_{He^+}/n_{H^+}$ ratio.
Anderson, L. D., Churchwell, E., Roshi, D. Anish   +2 more
arxiv   +5 more sources

Microscopic two-fluid theory of rotational constants of the OCS-H$_2$ complex in $^4$He droplets [PDF]

, 2003
We present a microscopic quantum analysis for rotational constants of the OCS-H$_2$ complex in helium droplets using the local two-fluid theory in conjunction with path integral Monte Carlo simulations. Rotational constants are derived from effective moments of inertia calculated assuming that motion of the H$_2$ molecule and the local non-superfluid ...
K. Birgitta Whaley, Patel M., Yongkyung Kwon   +2 more
arxiv   +3 more sources

Properties of Dense Fluid Hydrogen and Helium in Giant Gas Planets [PDF]

, 2007
Equilibrium properties of hydrogen-helium mixtures under thermodynamic conditions found in the interior of giant gas planets are studied by means of density functional theory molecular dynamics simulations. Special emphasis is placed on the molecular-to-atomic transition in the fluid phase of hydrogen in the presence of helium. Helium has a substantial
Burrows, Guillot, Kresse, Kresse, Kresse, Kresse, Mattson, Mayor, Militzer, Perdew, Pfaffenzeller, Rivera, Saumon, Troullier, Vorberger   +14 more
arxiv   +4 more sources