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Browsing by Subject "Stars: pre-main sequence"

Browsing by Subject "Stars: pre-main sequence"

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  • Azimuthal structures in the wind and chromosphere of the Herbig AE star AB Aurigae. Results from the MUSICOS 1992 campaign 
    Boehm, T; Catala, C; Donati, J. F; Welty, A; Baudrand, J; Butler, C. J; Carter, B; Collier-Cameron, A; Czarny, J; Foing, B; Ghosh, K; Hao, J; Houdebine, E; Huang, L; Jiang, S; Neff, J. E; Rees, D; Semel, M; Simon, T; Talavera, A; Zhai, D; Zhao, F (European Southern Observatory, 1996-12)
    The observations of the MUSICOS 1992 campaign concerned three scientific programs, among which was the study of azimuthal structures in the wind and chromosphere of the pre-main sequence Herbig Ae star AB Aur. The He I ...
  • The Curious Case of PDS 11: A Nearby, >10 Myr Old, Classical T Tauri Binary System 
    Mathew, B; Manoj, P; Bhatt, B. C; Sahu, D. K; Maheswar, G; Muneer, S (IOP Publishing, 2017-05)
    We present results of our study of the PDS 11 binary system, which belongs to a rare class of isolated, high Galactic latitude T Tauri stars. Our spectroscopic analysis reveals that PDS 11 is an M2–M2 binary system with ...
  • Enhanced luminosity of young stellar objects in cometary globules 
    Maheswar, G; Bhatt, H. C (Springer, 2008-06)
    In this study we investigated the effects of external trigger on the characteristics of young stellar objects (YSOs) associated with cometary globules (CGs). We made optical spectroscopy of stars associated with star-forming ...
  • Evolution of emission line activity in intermediate mass young stars 
    Manoj, P; Bhatt, H. C; Maheswar, G; Muneer, S (American Astronomical Society, 2006-12-10)
    We present optical spectra of 45 intermediate-mass Herbig Ae/Be stars. Together with the multiepoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by ...
  • Excitation Mechanism of O i Lines in Herbig Ae/Be Stars 
    Mathew, v; Manoj, P; Narang, Mayank; Banerjee, D. P. K; Pratheeksha Nayak; Muneer, S; Vig, S; Kumar, S. P; Paul, K. T; Maheswar, G (IOP Publishing, 2018-04-10)
    We have investigated the role of a few prominent excitation mechanisms viz. collisional excitation, recombination, continuum fluorescence, and Lyman beta fluorescence on the O i line spectra in Herbig Ae/Be stars. The aim ...
  • Optical Photometric and Polari metric investigation of NGC 1931 
    Pandey, A. K; Eswaraiah, C; Sharma, S; Samal, M. R; Chauhan, N; Chen, W. P; Jose, J; Ojha, D. K; Yadav, Ram Kesh; Chandola, H. C (IOP Publishing, 2013-02-05)
    We present optical photometric and polarimetric observations of stars toward NGC 1931 with the aim of deriving cluster parameters such as distance, reddening, age, and luminosity/mass function as well as understanding dust ...
  • Optical spectroscopic and 2MASS measurements of Stephenson Halpha stars 
    Maheswar, G; Manoj, P; Bhatt, H. C (European Southern Observatory, 2003-05)
    We present the results of spectroscopic observations for 52 objects from the list of Halpha emission stars of Stephenson (\cite{Ste86}). Out of six known T Tauri stars observed, five showed Halpha in emission and in one ...
  • Reappearance of McNeil’s Nebula (V1647 Orionis) and its Outburst Environment 
    Ninan, J. P; Ojha, D. K; Bhatt, B. C; Ghosh, S. K; Mohan, V; Mallick, K. K; Tamura, M; Henning, T (IOP Publishing, 2013-12-01)
    We present a detailed study of McNeil's nebula (V1647 Ori) in its ongoing outburst phase starting from 2008 September to 2013 March. Our 124 nights of photometric observations were carried out in optical V, R, I, and ...
  • Star formation around three co-moving HAeBe stars in the Cepheus Flare 
    Saha, Piyali; Maheswar, G; Mathew, B; Kamath, U. S (EDP Sciences, 2021-09)
    The presence of three more Herbig Ae/Be (HAeBe) candidates in the Cepheus Flare within a 1.5° radius centered on HD 200775 suggests that star formation is prevalent in a wider region of the LDN 1147/1158, LDN 1172/1174, ...
  • Stara -Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau 
    Guo, Zhen; Herczeg, Gregory J; Jose, J; Fu, Jianning; Chiang, Po-Shih; Grankin, Konstantin; Michel, R; Yadav, Ram Kesh; Liu, Jinzhong; Chen, Wen-Ping; Li, Gang; Xue, Huifang; Niu, Hubiao; Subramaniam, A; Sharma, Saurabh; Prasert, Nikom; Flores-Fajardo, Nahiely; Castro, Angel; Altamirano, Liliana (IOP Publishing, 2018-01)
    The variability of young stellar objects is mostly driven by star – disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths ...
  • Study of emission line stars in young open clusters 
    Mathew, B; Subramaniam, A (Astronomical Society of India, 2011)
    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 ...
  • Triggered Star Formation and Young Stellar Population in Bright-rimmed Cloud SFO 38 
    Choudhury, R; Mookerjea, B; Bhatt, H. C (IOP Publishing, 2010-07-10)
    We have investigated the young stellar population in and around SFO 38, one of the massive globules located in the northern part of the Galactic H II region IC 1396, using the Spitzer IRAC and MIPS observations (3.6-24 ...
  • TW Hya: Spectral Variability, X-Rays, and Accretion Diagnostics 
    Dupree, A. K; Brickhouse, N. S; Cranmer, S. R; Luna, G. J. M; Schneider, E. E; Bessell, M. S; Bonanos, A; Crause, L. A; Lawson, W. A; Mallik, S. V; Schuler, S. C (IOP Publishing, 2012-05-01)
    The nearest accreting T Tauri star, TW Hya was intensively and continuously observed over ~17 days with spectroscopic and photometric measurements from four continents simultaneous with a long segmented exposure using the ...
  • An unusual very low-mass high-amplitude pre-main sequence periodic variable 
    Rodríguez-Ledesma, M. V; Mundt, R; Ibrahimov, M; Messina, S; Parihar, P. S; Hessman, F. V; Alves de Oliveira, C; Herbst, W (EDP Sciences, 2012-08)
    Aims. We have investigated the nature of the variability of CHS 7797, an unusual periodic variable in the Orion Nebula Cluster. Methods. An extensive I-band photometric data set of CHS 7797 was compiled between 2004−2010 ...
  • Variable circumstellar activity of V351 Orionis 
    Choudhury, R; Bhatt, H. C; Pandey, G (EDP Sciences, 2011-02)
    Context. Emission and absorption line profiles which are formed in the interaction of pre-main sequence stars and their circumstellar environment are found to be variable at various timescales. Aims. We investigate the ...

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