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Browsing by Author "Muneer, S"

Browsing by Author "Muneer, S"

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  • 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 ...
  • Magnetic nature of coronal loops 
    Singh, J; Muneer, S; Sakurai, T; Ichimoto, K (Astronomical Society of India, 2007-12)
    It is generally believed that the magnetic pressure is much higher than the gas pressure in the coronal loops and these loops are isothermal in nature. We made systematic observations of four strong coronal emission lines ...
  • The nature of chromospheric active regions on V410 Tauri 
    Mekkaden, M. V; Pukalenthi, S; Muneer, S; Bastian, A. B (Astronomical Society of India, 2005-12)
    We present spectroscopic observations in the region of H alpha and Li I lines of the weak emission T Tauri star V410 Tau obtained over 1999/2000, 2002/2003 and 2003/2004 seasons. The emission strength showed rotational ...
  • Nature of Tilt Angles of Sunspot Groups During the 22nd Solar Cycle 
    Muneer, S; Singh, J (Springer, 2002-10)
    Daily white-light images from Kodaikanal Observatory have been utilized to study the nature of tilt angles of sunspot groups during the 22nd solar cycle. 2416 spot groups have been measured to find the tilt angle. An average ...
  • A new photometric study of M14 (NGC 6402): an interpretation of the horizontal branch and beyond 
    Yepez, M. A; Arellano Ferro, A; Deras, D; Bustos Fierro, I; Muneer, S; Schröder, K. -P (Oxford University Press on behalf of Royal Astronomical Society, 2022-03)
    We present a CCD VI photometric study of the globular cluster M14. Particular attention is given to the variable stars. This allowed new classifications and cluster membership considerations. New variables are reported: 3 ...
  • A new study of the variable star population in the Hercules globular cluster (M13; NGC 6205) 
    Deras, D; Arellano Ferro, A; Lazaro, C; Bustos Fierro, I. H; Calderon, J. H; Muneer, S; Giridhar, S (Oxford University Press on behalf of the Royal Astronomical Society, 2019-06)
    We present the results from VI CCD time-series photometry of the globular cluster M13 (NGC 6205). From the Fourier decomposition of the light curves of RRab and RRc stars we found an average metallicity of [Fe/H]zw = −1.58 ...
  • A new three-band, two beam astronomical photo-polarimeter 
    Srinivasulu, G; Raveendran, A. V; Muneer, S; Mekkaden, M. V; Jayavel, N; Somashekar, M. R; Sagayanathan, K; Ramamoorthy, S; Rosario, M.; Jayakumar, K (Astronomical Society of India, 2014-09)
    We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary ...
  • New variables in M5 (NGC 5904) and some identification corrections 
    Arellano Ferro, A; Bramich, D. M; Giridhar, S; Luna, A; Muneer, S (Konkoly Observatory, 2015-04)
    We report twelve variables not previously detected in the globular cluster M5 (NGC 5904); one SX Phe and eleven semi-regular variables (SR). Their identifications, equatorial coordinates, ephemerides, and light curves are ...
  • NGC 6712: the variable star population of a tidally disrupted globular cluster 
    Deras, D; Arellano Ferro, A; Lazaro, C; Bustos Fierro, I. H; Calderon, J. H; Muneer, S; Giridhar, S (Oxford University Press on behalf of the Royal Astronomical Society, 2020-04)
    We present an analysis of VI CCD time-series photometry of globular cluster NGC 6712. Our main goal is to study the variable star population as indicators of the cluster mean physical parameters. We employed the Fourier ...
  • Observations of variables 
    Rosario, M. J; Muneer, S; Raveendran, A. V; Mekkaden, M. V (IBVS / Konkoly Observatory, 2010-12)
    UX Ari was observed on a total of 33 nights during December 2008-February 2010 in standard Johnson BV bands with the 34-cm tel escope of Vainu Bappu Observatory, Kavalur. All the measurements were made with respect to 62 ...
  • Orbital period modulation and spot activity in the RS CVn binary V711 Tauri 
    Muneer, S; Jayakumar, K; Rosario, M. J; Raveendran, A. V; Mekkaden, M. V (EDP Sciences, 2010-10)
    We attempt to establish the real nature of the orbital period variation and its relation to the spot activity of V711 Tau, and determine why the (B–V) colour of the star appears to be nearly independent of its V magnitude. ...
  • Period changes in the RR Lyrae stars of NGC 6171 (M107) 
    Arellano Ferro, A; Rosenzweig, P; Luna, A; Deras, D; Muneer, S; Giridhar, S; Michel, R (WILEY-VCH Verlag GmbH & Co., 2018-02)
    Based on photometric data obtained between 1935 and 2017, O −C diagrams were built for 22 RR Lyrae stars in the globular cluster NGC 6171, leading to the discovery of secular period changes in four variables for which we ...
  • Photometric and spectroscopic evolution of the Type IIP supernova SN 2004et 
    Sahu, D. K; Anupama, G. C; Srividya, S; Muneer, S (Blackwell Publishing, 2006-09)
    We present optical photometry and spectroscopy of the Type IIP supernova SN 2004et that occurred in the nearby galaxy NGC 6946. The observations span a time range of 8–541 d after explosion. The late time bolometric ...
  • Photometric, spectroscopic and polarimetric variability of the weak-emission T Tauri star HD 288313 
    Mekkaden, M. V; Muneer, S; Raveendran, A. V (Blackwell Publishing, 2007-07)
    Photometric observations over three seasons show HD 288313 to be a light variable with a 2.2636-d period. The observed V amplitudes lie in the range of 0.06–0.15 mag. The star showed appreciable changes in the brightness ...
  • Physical parameters of RR Lyrae stars in NGC 6171 
    Deras, D; Arellano Ferro, A; Muneer, S; Giridhar, S; Michel, R (WILEY-VCH Verlag GmbH & Co., 2018-08)
    We present an analysis of VI CCD time series photometry of the globular cluster NGC 6171. The main goal is to determine individual physical parameters for single‐mode RR Lyrae stars present in the field of view of our ...
  • Quasi-periodicity nature of the redshift distribution of active galactic nuclei 
    Lokanadham, B; Kiron, Y. R; Muneer, S (Astronomical Society of India, 1998-12)
  • Results from a spectroscopic survey in the CoRoT fields. I. Search for chromospherically active stars 
    Medhi, B. J; Messina, S; Parihar, P. S; Pagano, I; Muneer, S; Duorah, K (EDP Sciences, 2007-07)
    Aims.In this paper we report the results of the spectroscopic survey we carried out to detect chromospheric activity of late-type stars in the fields of view of the CoRoT space mission. Methods.We give an accurate MK ...
  • RR Lyrae stars and the horizontal branch of NGC 5904 (M5) 
    Ferro, A. A; Luna, A; Bramich, D. M; Giridhar, S; Ahumada, J. A; Muneer, S (Springer, 2016-05)
    We report the distance and [Fe/H] value for the globular cluster NGC 5904 (M5) derived from the Fourier decomposition of the light curves of selected RRab and RRc stars. The aim in doing this was to bring these ...
  • RR Lyrae Stars in the Globular Cluster Palomar 2 
    Ferro, A. Arellano; Fierro, Bustos; Muneer, S; Giridhar, S (Universidad Nacional Autonoma De Mexico, 2023-04)
    A CCD VI imaging time-series over 11-year is employed to explore the light curves of stars in the field of Palomar 2. We discovered 20 RRab and 1 RRc variables. A revision of Gaia-DR3 data enabled us to identify 10 more ...
  • Spectroscopic analysis of four post-AGB candidates 
    Molina, R. E; Giridhar, S; Pereira, C. B; Arellano Ferro, A; Muneer, S (Institute de Astronomia, 2014-10)
    We have done a detailed abundance analysis of four unexplored cand idate post- Asymptotic Giant Branch(AGB) stars IRAS 13110- 6629, IRAS 175 79 - 3121, IRAS 18321- 1401 and IRAS 18489- 0629 using high resolution spectra. ...

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