ChemInform Abstract: THE URANIUM‐NICKEL‐COBALT (U‐UNI2‐UCO2) SYSTEM

Dreizler, Willi; Aldinger, Fritz; Petzow, G.

doi:10.1002/chin.198012013

Cited by 3 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kawaler et al (1995) used this procedure, along with the then-current spectroscopic temperature of 80,000K, to determine the mass and luminosity of PG 2131, and therefore its seismic distance. Later, Dreizler & Heber (1998) revised the temperature upward to 95,000K. We used the revised temperature, and the models shown in Figures 2-4, to recalculate the parameters of PG 2131.…”

Section: Seismological Analysismentioning

confidence: 99%

PG 2131+066: A Test of Pre–White Dwarf Asteroseismology

Reed

Kawaler

O'Brien

2000

ApJ

View full text Add to dashboard Cite

PG 2131+066 is a composite-spectrum binary with a hot pulsating PG 1159-type pre-white dwarf and an early M-type main sequence star. Analysis of Whole Earth Telescope observations of the pulsating pre-white dwarf component provided an asteroseismological determination of its mass, luminosity, and effective temperature. These determinations allowed Kawaler et al. (1995) to determine the distance to this star. In this paper, we refine the asteroseismological distance determination, and confirm the distance by an independent measurement to the system via the spectroscopic parallax of the M star. PG 2131+066 was observed by the HST using the original PC in September 1993. Exposures with filters F785LP and F555W both showed the companion at a distance of 0.3 arc seconds. Photometry of the images provides an apparent magnitude for the main sequence companion of m v = 18.97 ± 0.15, from which we find a distance of 560 +200 −134 pc. We also recalculated the asteroseismological distance to the pre-white dwarf using updated models and new spectroscopic constraints from UV spectra. The new seismological distance is 668 +78 −83 parsecs, in satisfactory agreement with the distance of the secondary star. These results suggest that this is indeed a physical binary, and that the seismological distance determination technique may be the best way to determine the distance to the pulsating hot pre-white dwarf stars.

show abstract

Section: Seismological Analysismentioning

confidence: 99%

PG 2131+066: A Test of Pre–White Dwarf Asteroseismology

Reed

Kawaler

O'Brien

2000

ApJ

View full text Add to dashboard Cite

show abstract

“…The congruent melting temperatures of the intermediate phases Co 11 U 2 and Co 4 U were undetermined, which were respectively estimated to be 1130°C and 1120°C by Ishida and Nishizawa [21]. The compound Co 3 U is stable up to the peritectoid temperature of 830°C, and the Co 2 U compound, with a homogeneity range from 27 to 33 at.% U is stable up to the congruent temperature of 1185°C [23]. The solubility of U in the fcc (Co) and hcp (Co) phases can be neglected.…”

Section: The Co-u Systemmentioning

confidence: 99%

“…2, which is based primarily on the work of Waldron and Brown [22] and the reviewed data of Dreizler et al [23]. However, the phase diagram of Temperature / ºC L fcc (Al) ref.…”

Section: The Co-u Systemmentioning

confidence: 99%

Thermodynamic modeling of the Al–U and Co–U systems

Wang

Liu

Wang

2008

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…These facts suggest that the superconducting behavior might be due to an impurity phase in the UCo crystal. Considering the U-Co binary alloy phase diagram 7) and the similarity of a superconducting transition temperature, we suspected the inclusion of some U 6 Co phase with T c ∼ 2 K. In order to confirm the inclusion of impurity phase, we measured the composition of a single crystal using Co-Kα fluorescence x-ray by EPMA. We clearly observed separated Co-poor domains as shown in Fig.…”

Section: Sa101-1 J P H Y S S O C J P N D O W N L O a D E D F mentioning

confidence: 99%

“…This point is easily understood on taking account of the large Sommerfelt coefficient value (126 mJ/K 2 ·mol) of U 6 Co. Further, it can be naturally expected that U 6 Co impurity phase exists in UCo considering U-Co binary alloy phase diagram. 7) UCo is an incongruent compound with a eutectic between the UCo and U 6 Co phases. Although the starting composition is U : Co = 1 : 1, the U-Co liquid composition is shifted to the U-rich side with decreasing temperature.…”

Section: )mentioning

confidence: 99%

Detailed Characterization of U–Co Binary Compounds

et al. 2011

View full text Add to dashboard Cite

We have measured the electrical resistivity and specific heat to 0.3 K on a Czochralski-grown single crystal of UCo. The electrical resistivity shows superconductivity below T c ∼ 1.9 K but with a small associated specific heat anomaly, as earlier reported for polycrystalline material. We determined that the superconductivity in our crystal arises from inclusion of impurity U 6 Co, and that UCo is a non-superconducting paramagnet down to 0.3 K with an electronic specific heat coefficient γ of 4.5 mJ/K 2 ·mol.

show abstract

ChemInform Abstract: THE URANIUM‐NICKEL‐COBALT (U‐UNI2‐UCO2) SYSTEM

Cited by 3 publications

References 0 publications

PG 2131+066: A Test of Pre–White Dwarf Asteroseismology

PG 2131+066: A Test of Pre–White Dwarf Asteroseismology

Thermodynamic modeling of the Al–U and Co–U systems

Detailed Characterization of U–Co Binary Compounds

Contact Info

Product

Resources

About