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Browsing by Subject "Stellar evolution"

Browsing by Subject "Stellar evolution"

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  • Abundance analysis of extreme helium stars 
    Pandey, G; Kameswara Rao, N; Lambert, D. L; Jeffery, C. S; Asplund, M (Astronomical Society of India, 2000)
    High resolution spectra were obtained for a sample of hydrogen-deficient stars which are hotter than the R CrB stars and cooler among the extreme helium stars (EHe). We believe that these stars are transition objects ...
  • The Carbon Star DY Persei May Be a Cool R Coronae Borealis Variable 
    Garcia-Hernandez, D. A; Kameswara Rao, N; Lambert, David L; Eriksson, K; Reddy, A. B. S; Masseron, Thomas (American Astronomical Society, 2023-05-01)
    Optical and near-IR photometry suggests that the carbon star DY Persei exhibits fadings similar to those of R Coronae Borealis (RCB) variables. Photometric surveys of the Galaxy and Magellanic Clouds uncovered new DY Per ...
  • Chemical Composition of Selected Metal Poor Stars 
    Ambika, S (Indian Institute of Astrophysics, Bangalore, 2004-07)
  • CN 1-1 - A peculiar compact planetary nebula 
    Bhatt, H. C; Mallik, D. C. V (The European Southern Observatory, 1986-11)
    Cn 1-1 is an emission-line object that shows strong emission lines characteristic of high density planetary nebulae superposed on the stellar spectrum of an F5 III-IV star. The authors estimate the absolute luminosity of ...
  • Detached cold dust shell around the early R star (warm carbon star) HD 100764 
    Parthasarathy, M (The European Southern Observatory, 1991-07)
    The existence of a dust shell and warm dust near HD 100764 are determined from IRAS observations of early R stars, and the ramifications of the findings are discussed. The mass of the dust shell is calculated to be 0.510 ...
  • Detached cold dust shells around yellow variable supergiants TW Aql, AI CMi, V 925 SCO and related stars 
    Parthasarathy, M; Reddy, B. E (Astronomical Society of India, 1993)
    TW Azl, AI CMi, V 924 Sco, ST Pup, AX Sgr, AD Aql, V1027 Cyg are yellow variable supergiants. We find these stars to be far-infrared (IRAS) sources with flux maximum around 25 micrometers. Analysis of the IRAS fluxes shows ...
  • Dynamical evolution of binary systems 
    Mohammed Alladin, S (Astronomical Society of India, 1990)
    The interaction of binary stars with single stars and the role of binary stars in star clusters are discussed. Some aspects of galaxy interactions are mentioned which can be viewed as analogs of binary-single body encounters ...
  • Evolution of lithium in low-mass giants: an observational perspective 
    Bharat Kumar, Yerra; Reddy, B. E (Indian Academy of Sciences, 2020-12)
    The overabundance of lithium in low-mass red giants has been a topic of interest for over four decades. Low-mass stars are expected to destroy lithium gradually throughout their lifetimes. Against this expectation, about ...
  • The evolutionary considerations of R CR B stars - Observational approach 
    Kameswara Rao, N (Astronomical Society of India, 1990)
    The properties of the hydrogen-deficient stars called extreme helium stars, R Cr B stars, and hydrogen-deficient carbon stars are briefly examined, emphasizing the R Cr B stars. Luminosities and temperatures, distribution ...
  • Formation of a binary in the general three-body problem 
    Bhatnagar, K. B (Astronomical Society of India, 1990)
    This paper reviews the role of triple encounters in the evolution of stellar systems. If a symmetric triple collision is perturbed, a family of asymmetric triple close approaches with arbitrary escape velocities and with ...
  • A high-resolution spectroscopic analysis of the suspected spectroscopic binary HD 165553 
    Goswami, A; Kameswara Rao, N; Lambert, D. L (The Observatory, 2004-02)
    The results of an analysis of a high-resolution spectrum of the possible spectroscopic binary HD 165553, obtained with a spectral resolving power of ~ 60 000, are presented. A detailed chemical-composition study indicates ...
  • Investigation of the helium enhancement in a super lithium-rich giant HD 77361 
    Hema, B. P; Pandey, G (Indian Academy of Sciences, 2020-12)
    In this work, the helium-enhancement (He-enhancement) in the lithium-rich (Li-rich) K-giant HD 77361 is investigated using the strengths of the MgH band and the Mg I lines. The detailed abundance analysis and also the ...
  • IRAS observations of R Cor Bor stars 
    Kameswara Rao, N; Nandy, K (Royal Astronomical Society, 1986-09)
    The IRAS observations of R Cr B, SU Tau and V 348 Sgr indicate the existence of a cool dust component of temperature about 30 K in R Cr B and SU Tau and less than or equal to 100 K in V 348 Sgr, in addition to the hot dust. ...
  • LS II +34 deg 26 is a low-mass post-asymptotic giant branch B supergiant and not a massive Population I B star located near the outer edge of the galaxy 
    Parthasarathy, M (American Astronomical Society, 1993-09-10)
    LS II +34 deg 26 is an 11th magnitude low-gravity, high-velocity and high Galactic latitude B1.5 Ia-Iabe supergiant star. It is found to be an IRAS source with far IR colors, flux distribution, and dust shell parameters ...
  • Modern astronomy : startling facts 
    Sivaram, C; Arun, K (Ane Books, 2009)
    The year 2009 is being recognised as the international year of astronomy (IYA) to mark the four hundredth anniversary of the historical occasion in the year 1609 when Galileo Galilei used the then newly invented telescope ...
  • Photometric elements, absolute dimensions and evolutionary status of the eclipsing binary HU Tauri 
    Parthasarathy, M; Sarma, M. B. K; Vivekananda Rao, P (Astronomical Society of India, 1993)
    The photometric elements of HU Tauri are derived from an analysis of its B and V light curve using the Wilson and Devinney (1971) light curve synthesis method. The photometric elements suggest that HU Tauri is a semi-detached ...
  • Post-AGB A-F supergiant stars 
    Parthasarathy, M; Reddy, B. E (Astronomical Society of India, 1993)
    We have searched the IRAS Polar Stratospheric Clouds (PSC) for dust shells around A-F supergiant stars similar to the high galactic latitude A-F supergiants with circumstellar dust shells. We have found that HD 114855 ...
  • Pulsars and binary stars 
    Shukre, C. S (Astronomical Society of India, 1990)
    After brief introductions to the evolution of close binary systems, pulsars, and X-ray binaries, the evolution of the study of these systems is examined and the present state of understanding is addressed. The impact of ...
  • Revised elements and Evolutionary status of six eclipsing binary stars 
    Chaubey, U. S (Astronomical Society of India, 1984-09)
    Twelve photoelectric light curves of six eclipsing binary stars namely GG Cas, WX Cep, UZ Cyg, AQ Peg and ST Per in two different filetrs (B and V for the first five binaries and R and I for ST Per) have been analysed by ...
  • Spectrophotometric studies of Am stars 
    Babu, G. S. D; Shylaja, B. S (D. Reidel Publishing Company, 1982-04)
    The relationships among the various physical parameters, namely the effective temperatures, radii and bolometric magnitudes, determined on the basis of the energy distribution curves of 25 Am stars are investigated. The ...

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