Browsing by Subject "Stellar Evolution"

Abundance analysis of the long period southern Cepheid RZ Vel

Giridhar, S; Goswami, A; Arellano Ferro, A (Indian Academy of Sciences, 1991-03)

An abundance analysis is conducted for the long period (P = 20.4 days), young classical Cepheid RZ Vel, a recognized member of an OB association. The results of the analysis are compared with the photometric study by Eggen ...

Asymmetric lepton production in a universe with non-zero baryon number

Sivaram, C (Springer, 1982-03)

Due to processes occurring during different stages of stellar evolution, a universe with a net baryon number develops an excess of neutrinos and positrons over antineutrinos of the same order as the observed relative ...

Birth and early evolution of a planetary nebula

Bobrowsky, M; Sahu, K. C; Parthasarathy, M; García-Lario, P (Nature Publishing Group, 1998-04)

The final expulsion of gas by a star as it forms a planetary nebula - the ionized shell of gas often observed surrounding a young white dwarf - is one of the most poorly understood stages of stellar evolution,. Such nebulae ...

The chemical composition of Algol systems. II - The carbon and nitrogen abundances of the secondaries of U CEP and U SGE

Parthasarathy, M; Lambert, D. L; Tomkin, J (Royal Astronomical Society, 1983-06)

The chemical composition of algol systems. III - Beta Lyrae-nucleosynthesis revealed

Balachandran, S; Lambert, D. L; Tomkin, J; Parthasarathy, M (Royal Astronomical Society, 1986-04)

The B8 primary of the eclipsing binary star Beta Lyr is subjected to high S/N ratio Reticon observations of the visible and near-IR lines of He, C, N, O, Ne, and Fe, in order to determine their abundances. N is noted to ...

Chemical evolution coefficients for the study of galactic evolution

Mallik, D. C. V (D.Reidel Publishing Co.,, 1981-05)

A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nucleosynthesis has been emphasized. A ...

Chromospheric activity of late-type giants and supergiants: reappearance of dynamo activity in the interior due to the spin-up of the core in evolution

Uchida, Yutaka; Bappu, M. K. V (Indian Academy of Sciences, 1982-07)

Chromospheric emission intensities and stellar evolution

Bappu, M. K. V (Indian Academy of Sciences, 1982-01-05)

Classical Cepheids and the local chemical inhomogeneities in the galactic disc

Giridhar, S (1986-06)

Places of formation have been derived for a sample of 23 Cepheids with well-determined atmospheric abundances in an attempt to study the chemical inhomogeneities in the local interstellar medium. The abundance data available ...

A classification scheme for pulsars

Kochhar, R. K (Nature Publishing Group, 1977-11)

The implications of a pulsar classification scheme are discussed. Three types of pulsars are distinguished - Type S (S for single) from supernova explosions of single stars; type D (D for disrupted) from binaries disrupted ...

Consequences of a chromospheric temperature rise on the formation of the H-alpha line in late-type supergiants

Mallik, S. G. V; Mallik, D. C. V (Royal Astronomical Society, 1988-08)

Computations of the H-alpha line profiles were performed in a non-LTE moving chromosphere with temperature rise to simulate the observed H-alpha characteristics in G and K supergiants. The comoving frame radiative transfer ...

The far-infrared (IRAS) excess in HD 161796 and related stars

Parthasarathy, M; Pottasch, S. R (European Southern Observatory, 1986-01)

The far infrared IRAS measurements of the high galactic latitude F-supergiant HD 161796 and related stars are found to show strong far infrared excesses, due to large amounts of dust around them. For HD 161796 the dust ...

Galactic Age Estimates from O-rich Stardust in Meteorites

Nittler, L. R; Cowsik, R (The American Physical Society, 1997-01)

The sup16Osup/17 supO and sup16O/sup18O ratios of refractory oxide grains extracted from primitive meteorites suggest that they originated in low-mass red giant stars prior to the formation of the Solar System 4.6×10/sup9 ...

Gravitational instability of interstellar magnetic clouds

Ghosh, K. K; Bhattacharyya, J. C (D. Reidel Publishing Co.,, 1985-12)

The gravitational instability of a nonrotating isothermal gaseous disk permeated by a uniform frozen-in magnetic field is investigated using a fourth-order perturbation technique. From the results it is found that the disk ...

HD 77361: a new case of super Li-rich K giant with anomalous low C-12/C-13 ratio

Bharat Kumar, Y; Reddy, B. E (The American Astronomical Society, 2009-09)

Results from high-resolution spectroscopic analysis of HD77361 are reported. LTE analysis shows that HD77361 is a K giant of atmospheric parameters: T-eff = 4580 +/- 75 K, log g = 2.5 +/- 0.1, and xi(t) = 1.40 +/- 0.5 km ...

IIA Newsletter, Vol.5, No.1, January 1990

Prabhu, T. P; Pati, A. K (Indian Institute of Astrophysics, 1990-01)

Kinematical distances to open star clusters

Sagar, R; Bhatt, H. C (Indian Academy Sciences, 1988-06)

Kinematical distances are estimated for six open star clusters. They agree fairly well with the photometric distances. The kinematical distances cannot, at present, be estimated better than the photometric distances. When ...

Lower bounds on neutron star mass and moment of inertia implied by the millisecond pulsar

Datta, B; Ray, A (The Royal Astronomical Society, 1983-08)

The short period of the millisecond pulsar PSR 1937+214 implies that it could be close to the onset of rotational instabilities. Conditions of rotational stability imply lower bounds on the mass and moment of inertia and ...

The Neutron in Astrophysics

Sivaram, C (Astronomical Society of India, 1983-06)

On the consequences of a new initial-final mass relation for low and intermediate mass stars and the birthrate of planetary nebulae

Mallik, D. C. V (Gordon and Breach Science Publishers, 1985)

Recent work on the initial-final mass relation for low-and intermediate-mass stars and the mass distribution of the nuclei of planetary nebulae sets a lower limit on the initial mass of progenitors of PN which is substantially ...

Browsing by Subject "Stellar Evolution"

Browsing by Subject "Stellar Evolution"

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