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Browsing by Subject "Stars"

Browsing by Subject "Stars"

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  • An Analysis of Ultraviolet Spectra of Extreme Helium Stars and New Clues to Their Origins 
    Pandey, G; Lambert, D. L; Simon, C. S; Kameswara Rao, N (University of Chicago Press, 2006-02)
    Abundances of about 18 elements including the heavy elements Y and Zr are determined from Hubble Space Telescope Space Telescope Imaging Spectrograph ultraviolet spectra of seven extreme helium stars (EHes): LSE 78, BD +10 ...
  • Aperture synthesis in optical astronomy; the current status 
    Saha, S. K (Invertis, Inc, 2007)
    A milestone in observational astronomy was achieved when the interferometric fringes of Lyrae (Vega) in the visible band were obtained in July 1974, by A. Labeyrie from an interferometer, called Interferometre a deux ...
  • Asymptotic giant branch stars in the ISOGAL survey 
    Ojha, D. K; Omont, A; Simon, G; Blommaert, J (Astronomical Society of India, 2000)
    We present and analyse the data of a field at 1 = 0o, b = +1o from the ISOGAL survey of selected areas of the inner Galactic bulge at 15 and 7 ?m. In combination with IJKs data from the near-infrared southern sky survey ...
  • Automated classification and stellar parameterization 
    Giridhar, S; Muneer, S; Goswami, A (Memorie della Societa Astronomica Italiana, 2006)
    Different approaches for automated spectral classification are critically reviewed. We describe in detail ANN based methods which are very efficient in quick handling of the large volumes of data generated by different ...
  • BV Photometry and Hα Spectroscopy of the Rs-Canum Binary II-Pegasi 
    Mohin, S; Raveendran, A. V (European Southern Observatory, 1993-09)
    Differential BV photometry of II Peg obtained on a total of 57 nights during the years 1986-1991 and Hα spectroscopy obtained on 12 nights during the 1990-1991 observing season are presented. From an analysis of the available ...
  • Classification of Nova Spectra 
    Anupama, G. C (Astronomical Society of India, 2012)
    The evolution of the optical spectrum of a nova outburst is described. The classification schemes used to classify novae based on the outburst spectral features and their evolution are discussed.
  • Classification of ultraviolet stellar spectra using artificial neural networks 
    Gulati, R. K; Gupta, R; Gothoskar, P; Khobragade, S (Astronomical Society of India, 1996)
    Scheme based on the artificial neural networks (ANNs) trained with multi-layer back propagation using single level network for classifying ultraviolet spectra in the IUE Low-Dispersion Spectra Reference Atlas is presented. ...
  • The colors of Am Stars 
    Shylaja, B. S; Babu, G. S. D (Astronomical Society of the Pacific, 1993-01)
    The energy distribution of the Am stars are affected by the line blanketing, which appears as a deviation in the behaviour of color indices with reference to the normal stars. In this paper we study the various color indices ...
  • The Colors of Am-Stars 
    Shylaja, B. S (Astronomical Society of the Pacific, 1993-01)
  • Comparative modelling of the spectra of cool giants 
    Lebzelter, T; Heiter, U; Abia, C; Eriksson, K; Ireland, M; Neilson, H; Nowotny, W; Maldonado, J; Merle, T; Peterson, R; Plez, B; Short, C. I; Wahlgren, G. M; Worley, C; Aringer, B; Bladh, S; de Laverny, P; Goswami, A; Mora, A; Norris, R. P; Recio-Blanco, A; Scholz, M; Thevenin, F; Tsuji, T; Kordopatis, G; Montesinos, B; Wing, R. F (EDP Sciences, 2012-11)
    Context. Our ability to extract information from the spectra of stars depends on reliable models of stellar atmospheres and appropriate techniques for spectral synthesis. Various model codes and strategies for the analysis ...
  • Development of a stellar SPOT model 
    Nagar, P (Astronomical Society of Indian, 1989-09)
    A spectroscopic spot model has been developed incorporating spot magnetic fields. It is shown that the presence of spot magnetic field makes a noticeable effect on the shape of spectral lines
  • Duration of star formation in young open clusters 
    Bhavya, B; Subramaniam, A; Kuriakose, V. C (Astronomical Society of India, 2012)
    Young Open Clusters have always been a platform for the star formation studies. It was assumed that all members in the cluster are coeval, on the other hand, recent studies show the presence of an age range among the members ...
  • Dust in the Outer Layers of Stars 
    Ingalgi, M. F (Indian Institute of Astrophysics, Bangalore, 1990-08)
  • Effects of Dust in Distorted, Irradiated, and Expanding Atmospheres of Close Binary Components 
    Srinivasa Rao, M (Astronomical Society of Japan, 2003)
    We studied the transfer of line radiation with dust in distorted and expanding atmospheres of close binary components. We assumed that the distortion of the atmosphere is caused by self rotation and a tidal force exerted ...
  • Emission Spectrum of Hot R CrB star Mv Sgr 
    Kameswara Rao, N; Houziaux, L; Giridhar, S (Indian Academy Sciences, 1990-03)
    The new spectroscopic observation of MV Sgr obtained at ESO in 1987july shows enhanced emission lines of He I , λ 3889, [S II ] λ 4068 relative to the observations discussed by Jeffrey et al. (1988). The presence of [SII] ...
  • Evolution of Lithium Abundance in Pop I Giants 
    Mallik, S. G. V (International Astronomical Union, 2000)
    Recent observations of cool giants have shown that there exists a large range in their lithium abundances even for apparently similar stars. In order to explore whether this large spread could be interpreted in terms of ...
  • Evolutionnary Stages of Stars Exhibiting Nonradial Pulsations 
    Mohan, C (Astronomical Society of India, 1976-09)
  • Extragalactic star formation rate -- estimates at different wavelengths 
    Prabhu, T. P (Astronomical Society of India, 2012)
    The star formation rate (SFR) in galaxies is of prime importance in the study of formation and evolution of galaxies. Different methods have hence been evolved to estimate the current SFR in galaxies, using indicators at ...
  • The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole? 
    Perley, D. A; Mazzali, P. A; Yan, Lin|; Cenko, S. Bradley; Gezari, Suvi; Taggart, Kirsty; Blagorodnova, Nadia; Fremling, Christoffer; Mockler, Brenna; Singh, A; Tominaga, Nozomu; Tanaka, Masaomi; Watson, Alan M; Ahumada, Tomas; Anupama, G. C; Ashall, Chris; Becerra, Rosa L; Bersier, David; Bhalerao, Varun; Bloom, Joshua S; Butler, Nathaniel R; Copperwheat, Chris; Coughlin, Michael W; De, Kishalay; Drake, Andrew J; Duev, Dmitry A; Frederick, Sara; Gonzalez, J. J; Goobar, Ariel; Heida, Marianne; Ho, Anna Y. Q; Horst, John; Hung, Tiara; Itoh, Ryosuke; Jencson, Jacob E; Kasliwal, Mansi M; Kawai, Nobuyuki; Khanam, Tanazza; Kulkarni, Shrinivas R; Brajesh Kumar; Harsh Kumar; Kutyrev, Alexander S; Lee, William H; Maeda, Keiichi; Ashish Mahabal; Murata, Katsuhiro L; Neill, James D; Ngeow, Chow-Choong; Penprase, Bryan; Pian, Elena; Quimby, Robert; Ramirez-Ruiz, Enrico; Richer, Michael G; Roman-Zuniga, Carlos G; Sahu, D. K; Srivastav, S; 9 others (Oxford University Press on behalf of the Royal Astronomical Society, 2019-03)
    Wide-field optical surveys have begun to uncover large samples of fast (trise ≲ 5 d), luminous (Mpeak < −18), blue transients. While commonly attributed to the breakout of a supernova shock into a dense wind, the great ...
  • 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 ...

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