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Browsing by Subject "Stars: AGB and post-AGB"

Browsing by Subject "Stars: AGB and post-AGB"

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  • 1D radiative transfer models of 21 and 30 μm emission features in proto-planetary nebulae 
    Muthumariappan, C; Reddy, B. E (Cambridge University Press, 2012-08)
    Spectral energy distributions of six proto-planetary nebulae showing 21 and 30μ features were fit with models obtained from 1D radiative transfer code, taking FeO and MgS respectively are the carriers of the features. ...
  • Binarity and Accretion in AGB Stars: HST/STIS Observations of UV Flickering in Y Gem 
    Sahai, R; Contreras, C. S; Mangan, A. S; Sanz-Forcada, J; Muthumariappan, C; Claussen, M. J (IOP Publishing, 2018-06-20)
    Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to search for hot binary companions ...
  • CH stars at high Galactic latitudes 
    Goswami, A (Blackwell Publishing, 2005-05)
    Carbon-rich stars of Population II, such as CH stars, can provide direct information on the role of low- to intermediate-mass stars of the halo in early Galactic evolution. Thus accurate knowledge of the CH stellar population ...
  • Chemical composition of a sample of candidate post-asymptotic giant branch stars 
    Sumangala Rao, S; Giridhar, S; Lambert, D. L (Wiley-Blackwell, 2012-01)
    We have derived elemental abundances for a sample of nine IRAS sources with colours similar to those of post-asymptotic giant branch (post-AGB) stars. For IRAS 01259+6823, IRAS 05208−2035, IRAS 04535+3747 and IRAS 08187−1905, ...
  • Chemical Compositions of RV Tauri Stars and Related Objects 
    Sumangala Rao, S; Giridhar, S (Institute de Astronomia, 2014-04)
    We have undertaken a comprehensive abundance analysis for a sample of relatively unexplored RV Tauri and RV Tauri like stars to further our understanding of post-Asymptotic Giant Branch (post-AGB) evolution. From our study ...
  • Circumstellar dust shells of hot post-AGB stars 
    Gauba, G; Parthasarathy, M (EDP Sciences, 2004-04)
    Parameters of the circumstellar dust shells of 15 hot post-AGB stars have been derived using a radiative transfer code (DUSTY). Combining the optical, near and far-infrared (ISO, IRAS) data of the stars, we have reconstructed ...
  • Evolution of Hen 3-1357, the Stingray Nebula 
    Pena, Miriam; Parthasarathy, M; Ruiz-Escobedo, Francisco (Oxford University Press on behalf of Royal Astronomical Society, 2022-09)
    The spectroscopic evolution of Hen 3-1357, the Stingray Nebula, is presented by analysing data from 1990 to 2021. High-resolution data obtained in 2021 with South African Large Telescope High Resolution Spectrograph and ...
  • Gaia DR2 and EDR3 data and evolutionary status of post-AGB stars with high radial velocities 
    Aoki, Wako; Matsuno, Tadafumi; Parthasarathy, M (Oxford University Press on behalf of the Astronomical Society of Japan, 2022-12)
    Using the Gaia Data Release 2 (DR2) and Early Data Release 3 (EDR3) data and list of post-AGB candidates, we investigate the parallax, proper motion, and binarity for 20 post-AGB stars and candidates that have high radial ...
  • The Hamburg/ESO R-process Enhanced Star survey (HERES) VIII. The r+s star HE 1405 0822 
    Cui, W. Y; Sivarani, T; Christlieb, N (EDP Sciences, 2013-10)
    Aims. The aim of this study is a detailed abundance analysis of the newly discovered r-rich star HE 1405−0822, which has [Fe/H] = −2.40. This star shows enhancements of both r- and s-elements, [Ba/Fe] = + 1.95 and [Eu/Fe] ...
  • High-resolution spectroscopy of the extremely iron-poor post-AGB star CCâLyr 
    Aoki, W; Matsuno, Tadafumi; Honda, S; Parthasarathy, M (Astronomical Society of Japan, 2017-04)
    High-resolution optical spectroscopy was conducted for the metal-poor post-AGB star CC Lyr to determine its chemical abundances and spectral line profiles. Our standard abundance analysis confirms its extremely low ...
  • K-band spectra of selected post-AGB candidates 
    Parthasarathy, M; Muthumariappan, C; Muneer, S (Springer Nature, 2020-07)
    We present medium resolution (1000) K-band spectra of 12 post-AGB candidates and related stars. For several objects in our sample, these spectra were obtained for the first time. The Brγ line in emission is detected in ...
  • Line identification and photometric history of the hot post-AGB star Hen 3−1013 (IRAS 14331−6435) 
    Arkhipova, V. P; Parthasarathy, M; Ikonnikova, N. P; Ishigaki, M; Hubrig, S; Sarkar, G; Kniazev, A. Y (Oxford University Press on behalf of the Royal Astronomical Society, 2018-12)
    We present a study of the high-resolution optical spectrum for the hot post-asymptotic giant branch (post-AGB) star, Hen 3−1013, identified as the optical counterpart of the infrared source IRAS 14331−6435. For the first ...
  • A multiwavelength study of LS II+34 26: a hot post-AGB star in the process of becoming a planetary nebula 
    Garcia-Lario, P; Parthasarathy, M; de Martino, D; Sanz Fernandez de Cordoba, L; Monier, R; Manchado, A; Pottasch, S. R (European Southern Observatory, 1997-10)
    We present the results from a multiwavelength analysis of LS II+34 26, recently identified as a low mass post-AGB star and not a massive population I B-type star, as previously thought. We confirm that the central star is ...
  • The nature of the Stingray nebula from radio observations 
    Harvey-Smith, L; Hardwick, J. A; De Marco, O; Parthasarathy, M; Gonidakis, I; Shaila Akhter; Cunningham, M; Green, J. A (Oxford University Press on behalf of the Royal Astronomical Society, 2018-09)
    We have analysed the full suite of Australia Telescope Compact Array data for the Stingray planetary nebula. Data were taken in the 4–23 GHz range of radio frequencies between 1991 and 2016. The radio flux density of the ...
  • On the discovery of K I 7699 Å line strength variation during the 1982–1984 eclipse of ε Aurigae 
    Parthasarathy, M (Elsevier B.V, 2017-02)
    The discovery of K I 7699 Å line strength variations during the 1982–1984 eclipse of ε Aurigae is described. The equivalent widths and radial velocities of the K I 7699 Å line derived from spectra obtained during 1981 ...
  • Photometry and low resolution spectroscopy of hot post-AGB candidates 
    Gauba, G; Parthasarathy, M; Kumar, B; Yadav, R. K. S; Sagar, R (The European Southern Observatory, 2003-06)
    We have obtained Johnson U, B, V and Cousins R, I photometry and low resolution spectra of a small sample of hot post-AGB candidates. Using the present data in combination with JHK data from 2MASS, infrared data from the ...
  • Planetary nebulae with UVIT II. Revelations from far-UV vision of Butterfly nebula NGC 6302 
    Kameswara Rao, N; De Marco, O; Sriram, K; Murthy, J; Ray, A; Sutaria, F. K; Mohan, Rekhesh (EDP Sciences, 2018-12)
    The high excitation planetary nebula, NGC 6302, has been imaged in two far-ultraviolet (FUV) filters, F169M (Sapphire; λeff: 1608 Å)and F172M (Silica; λeff: 1717 Å) and two near-UV (NUV) filters, N219M (B15; λeff: 2196 Å) ...
  • Planetary nebulae with UVIT: A progress report 
    Kameswara Rao, N; Sutaria, F; Murthy, J; Ray, A; Pandey, G (Indian Academy of Sciences, 2021-10)
    The spectral region between 1250–3000 A contains important spectral lines to understand the ˚ morphological structures and evolution of planetary nebulae. This is the region sampled by UVIT through various filter bands ...
  • The puzzling high velocity G5 supergiant star HD 179821: new insight from Gaia DR2 data 
    Parthasarathy, M; Jasniewicz, G; Thevenin, F (Springer, 2019-01)
    HD 179821 is classified as G5 Ia star. From the IRAS colors and spectral energy distributions it was classified as a post-AGB star. But some studies classify it as a massive (30 to 19 M⊙) post-red supergiant evolving to ...
  • Radiative Transfer Modelling of Dust in IRAS 18333–2357: The only planetary nebula in the metal-poor globular cluster M22 
    Muthumariappan, C; Parthasarathy, M; Ita, Y (Oxford University Press on behalf of the Royal Astronomical Society, 2013-10-11)
    We report results from our 1-D radiative transfer modelling of dust in the hydrogen-deficient planetary nebula IRAS 18333–2357 located in the globular cluster M22. A spectral energy distribution was constructed from ...

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