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Browsing by Subject "Stars: Emission-Line"

Browsing by Subject "Stars: Emission-Line"

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  • Be phenomenon in open clusters: results from a survey of emission-line stars in young open clusters 
    Mathew, B; Subramaniam, A; Bhatt, B. C (The Royal Astronomical Society, 2008-08)
    Emission-line stars in young open clusters are identified to study their properties, as a function of age, spectral type and evolutionary state. 207 open star clusters were observed using the slitless spectroscopy method ...
  • High resolution spectroscopy of the high latitude rapidly evolving post-AGB star SAO 85766 (= IRAS 18062+2410) 
    Parthasarathy, M; García-Lario, P; Sivarani, T; Manchado, A; Sanz Fernández de Córdoba, L (European Southern Observatory, 2000-05)
    SAO 85766 (b = +20o) is an IRAS source with far-infrared colours similar to planetary nebulae. According to the HDE catalogue, its spectrum in 1940 was that of an A5 star. The UV fluxes and colours derived from data obtained ...
  • IUE and ISO observations of the bipolar proto-planetary nebula Hen 401 (IRAS 10178-5958) 
    Parthasarathy, M; García-Lario, P; Gauba, G; de Martino, D; Nakada, Y; Fujii, T; Pottasch, S. R; de Cordoba, L. S. F (EDP Sciences, 2001-09)
    We present ultraviolet (IUE) and infrared (ISO) observations of the bipolar proto-planetary nebula Hen 401 which, combined with previously available optical and near infrared data, are used to reconstruct the overall ...
  • Large-scale wind structures in OB supergiants: a search for rotationally modulated Hα variability 
    Morel, T; Marchenko, S. V; Pati, A. K; Kuppuswamy, K; Carini, M. T; Wood, E; Zimmerman, R (The Royal Astronomical Society, 2004-06)
    We present the results of a long-term monitoring campaign of the Hα line in a sample of bright OB supergiants (O7.5-B9) which aims at detecting rotationally modulated changes potentially related to the existence of large-scale ...
  • Low resolution spectroscopy of hot post-AGB candidates 
    Parthasarathy, M; Vijapurkar, J; Drilling, J. S (EDP Sciences, 2000-08)
    Spectral types are determined from low resolution optical spectra of 40 IRAS sources with far-infrared colours similar to planetary nebulae. The presence of circumstellar dust, high galactic latitude, and early supergiant ...
  • Observations of BN and AN stars: New Be stars 
    Ghosh, K. K; Apparao, K. M. V; Pukalenthi, S (The European Southern Observatory, 1999-01)
    From a survey of spectra of Bn/An stars, we have detected seven new Be stars: HR 1056 (A0Vn), 1544 (A1Vn), 2191 (A0Vnn), 2300 (B8Vn), 3134 (B9.5 Vn), 3878 (B0.5 IIIn) and 4552 (B9IIIpSi). H_alpha profiles of these stars ...
  • Optical spectroscopy of classical Be stars in open clusters 
    Mathew, B; Subramaniam, A (Astronomical Society of India, 2011-12)
    We present a spectroscopic study of 150 Classical Be stars in 39 open clusters using medium resolution spectra in the wavelength range 3800 – 9000 A° . Onethird of the sample (48 stars in 18 clusters) has been studied ...
  • Pre-main sequence stars, emission stars and recent star formation in the Cygnus region 
    Bhavya, B; Mathew, B; Subramaniam, A (Astronomical Society of India, 2007-09)
    The recent star formation history in the Cygnus region is studied using 5 clusters (IC 4996, NGC 6910, Berkeley 87, Biurakan 2 and Berkeley 86). The optical data from the literature are combined with the 2MASS data to ...
  • Spectroscopic survey of ASAS eclipsing variables: search for chromospherically active eclipsing binary stars - I 
    Parihar, P. S; Messina, S; Bama, P; Medhi, B. J; Muneer, S; Velu, C; Ahmad, A (Royal Astronomical Society, 2009-05)
    We have started a spectroscopic survey to identify new chromospherically active components and low-mass pre-main sequence (PMS) stars in recently discovered All Sky Automated Survey (ASAS) eclipsing binaries. In this paper, ...
  • Study of variability of the polarization in Herbig Ae/Be stars 
    Jain, S. K; Bhatt, H. C (European Southern Observatory, 1995-06)
    We report our measurements of linear polarization of a number of Herbig Ae/Be stars made at several epochs during the period 1989-1993. These results together with the observations compiled from the published sources have ...
  • The UV (IUE) spectrum of the planetary nebula PC 11 (HD 149427) 
    Parthasarathy, M; García-Lario, P; Pottasch, S. R; de Martino, D; Surendiranath, R (European Southern Observatory, 2000-03)
    The UV spectrum of PC 11 is found to show variations in the strength of the O III] 1666Å , N III] 1750Å and C III] 1909Å emission lines. The detection of continuum emission in the wavelength interval 2650Å to 3200Å indicates ...
  • Weak emission line [WELS] central stars of planetary nebulae are [WC]-PG1159 stars 
    Parthasarathy, M; Acker, A; Stenholm, B (European Southern Observatory, 1998-01)
    The characteristics of the spectra of weak emission line stars (WELS) are found to be very similar to that of [WC]-PG1159 and PG1159 objects. On the basis of the spectra we find 31 WELS central stars of planetary nebulae ...

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