IIA Institutional Repository

Browsing by Subject "Stellar envelopes"

Browsing by Subject "Stellar envelopes"

Sort by: Order: Results:

  • The 1985 outburst of RS Ophiuchi - Spectroscopic results 
    Anupama, G. C; Prabhu, T. P (Indian Academy of Sciences, 1989-09)
    Results are reported from visual spectroscopy of the recurrent nova RS Oph, obtained with a Cassegrain spectrograph on the 102-cm reflector at Vainu Bappu Observatory in February-May 1985 (days 32-108 postoutburst). The ...
  • Aberration and advection effects in expanding spherically symmetric shells 
    Peraiah, A (American Astronomical Society, 1991-04)
    The extreme outer layers of supernovae, novae, AGN, QSOs, and many supergiant stars are known to be in rapid expansion or contraction. In this paper, aberration and advection effects in a spherical medium scattering radiation ...
  • Anomalous dust in the environment of Herbig Ae/Be stars 
    Gorti, U; Bhatt, H. C (European Southern Observatory, 1993-04)
    Photometric data in the UBVRI bands of Herbig Ae/Be stars have been analyzed to study the wavelength dependence of extinction to these objects. The color excess ratios E(U-B)/E(B-V), E(V-R)/E(B-V), E(V-I)/E(B-V) and ...
  • BVRI polarimetry of carbon stars 
    Raveendran, A. V (European Southern Observatory, 1991-03)
    BVRI polarimetry of carbon stars belonging to different variability types - VX And, UU Aur, T Cae, Y CVn, U Hya, Y Hya, RY Mon, W Ori, Y Per, RT Pup, and X Vel - is presented. Though there is significant scatter, on the ...
  • 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 ...
  • Dust envelopes around RV Tauri stars 
    Raveendran, A. V (The Royal Astronomical Society, 1989-06)
    In the IRAS (12)-(25), (25)-(60) color-color diagram, RV Tauri stars are found to populate cooler temperature regions, distinctly different from those occupied by the oxygen and carbon Miras. The IRAS fluxes are consistent ...
  • Effects of aberration and advection on line formation 
    Peraiah, A (University of Chicago Press, 1991-10)
    The effects of inclusion of the aberration and advection terms in the equation of the line transfer are studied. Spherical shells whose ratios of outer (B) to inner (A) radii (B/A) are 2, 5, and 10 and with line-center ...
  • Effects of dust on the formation of lines in an expanding spherical medium 
    Peraiah, A; Varghese, B. A; Srinivasa Rao, M (The European Southern Observatory, 1987-06)
    A series of line profiles formed in a spherically symmetric and radially expanding atmosphere in which dust is present are computed, assuming that the dust scatters radiation isotropically. Two cases of dust distribution ...
  • Equivalent widths of hydrogen Lyman alpha line in an expanding spherical atmosphere 
    Peraiah, A; Ingalgi, M. F (Indian Academy of Sciences, 1990-06)
    The profiles of hydrogen Lyman-alpha line in an expanding spherical atmosphere containing dust and gas were calculated. The variation of equivalent widths with velocities of expansion of the atmosphere, together with the ...
  • The far-infrared (IRAS) excess in BQ() and related stars 
    Parthasarathy, M; Pottasch, S. R (European Southern Observatory, 1989-11)
    The FIR IRAS flux distributions and color of 12 peculiar emission-line objects (HD 51585, Hen 401, Hen 591, Hen 1013, He 2-138, M 2-9, HD 326971, Hen 1357, Hen 1428, Tc 1, Hen 1475, and M 1-26) are found to be similar to ...
  • The far-infrared (IRAS) excess in luminous F-G stars 
    Pottasch, S. R; Parthasarathy, M (European Southern Observatory, 1988-03)
    The far-infrared IRAS excesses are found in ten luminous F-G stars. The far-IR fluxes from these stars are due to large amounts of dust around them. The far-IR flux distribution, far-IR luminosities and dust masses are ...
  • An investigation of polarization produced by circumstellar dust envelopes 
    Raveendran, A. V (European Southern Observatory, 1991-03)
    Numerical computations show that: (1) the polarimetric behavior of carbon stars is inconsistent with the scattering by graphite grains, (2) the radial pulsation of the star does not significantly change the net polarization ...
  • 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. ...
  • Long-term polarimetric behaviour of the carbon Mira R Leporis 
    Raveendran, A. V; Kameswara Rao, N (European Southern Observatory, 1989-05)
    BVRI polarimetry of R Lep obtained during 1984-1987 shows large changes in the normalized wavelength dependence of polarization. It is found that both the amount and position angle of polarization had components which ...
  • 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 ...
  • Measurements of linear polarization of some Herbig Ae/Be stars 
    Jain, S. K; Bhatt, H. C; Sagar, R (The American Physical Society, 1990-05)
    The linear polarization of eight bright Herbig Ae/Be stars in UBVRI bands has been measured. No unique wavelength dependence of polarization magnitude or direction is found in these measurements. Comparison with earlier ...
  • Polarimetric observations of the RV Tauri star AR Puppis 
    Raveendran, A. V; Kameswara Rao, N (European Southern Observatory, 1988-03)
    UBVRI polarimetry of AR Pup is presented. Large variations are seen both in the amount and direction of polarization. On one occasion, the polarization in U was found to be as high as 14.6 percent. Polarization level ...
  • Radiative transfer with Compton scattering in spherically symmetric shells 
    Peraiah, A; Varghese, B. A (Astronomical Society of Japan, 1990)
    The radiative transfer equation with Compton scattering is solved for spherically symmetric shells. The purpose of the study is to determine how gamma rays or X-rays change their energies and how they become reflected and ...
  • Simultaneous infrared and H-alpha measurements of Be stars 
    Apparao, K. M. V; Tarafdar, S. P; Verma, R. P; Iyengar, K. V. K; Ghosh, K. K (Indian Academy of Sciences, 1993)
    The observed infrared excess in Be stars is usually interpreted as free-free and free-bound emission from a hot gas envelope around the Be star. This hot gas should also emit H-alpha line radiation. Earlier observations ...
  • Spectrophotometric studies of Ap stars 
    Babu, G. S. D; Shylaja, B. S (D. Reidel Publishing Company, 1982-01)
    Based on the observed energy distribution curves of about a hundred Ap stars, the various relationships among their physical parameters: namely, the temperatue, colour index, bolometric correction and bolometric magnitude ...

Search DSpace

Browse

My Account