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Browsing by Author "Pandey, G"

Browsing by Author "Pandey, G"

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  • Abundance analysis of extreme helium stars 
    Pandey, G; Kameswara Rao, N; Lambert, D. L; Jeffery, C. S; Asplund, M (Astronomical Society of India, 2000)
    High resolution spectra were obtained for a sample of hydrogen-deficient stars which are hotter than the R CrB stars and cooler among the extreme helium stars (EHe). We believe that these stars are transition objects ...
  • Abundance analysis of the cool extreme helium star LSS3378 
    Pandey, G; Reddy, B. E (Blackwell Publishing, 2006-07)
    Abundance analysis of the cool extreme helium (EHe) star LSS 3378 is presented. The abundance analysis is done using local thermodynamic equilibrium (LTE) line formation and LTE model atmospheres constructed for EHe ...
  • Abundances of Neutron-Capture Elements in the Hot Extreme Helium Stars V1920 Cygni and HD 124448 
    Pandey, G; Lambert, D. L; Kameswara Rao, N; Jeffery, C. S (The American Astronomical Society, 2004-02-20)
    Analysis of Hubble Space Telescope Space Telescope Imaging Spectrograph ultraviolet spectra of two hot extreme helium (EHe) stars, V1920 Cyg and HD 124448, provides the first measurements of abundances of neutron-capture ...
  • 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 ...
  • Are DY Persei Stars Cooler Cousins of R Coronae Borealis Stars? 
    Bhowmick, A; Pandey, G; Joshi, V; Ashok, N. M (IOP Publishing, 2018-02)
    Are DY Persei Stars Cooler Cousins of R Coronae Borealis Stars? Anirban Bhowmick 1 , Gajendra Pandey 1 , Vishal Joshi 2 , and N. M. Ashok 2 1 Indian Institute of Astrophysics, Koramangala, Bengaluru 560 034, ...
  • AstroSat Study of the Globular Cluster NGC 2298: Probable Evolutionary Scenarios of Hot Horizontal Branch Stars 
    Rani, Sharmila; Pandey, G; Subramaniam, A; Chung, Chul; Sahu, S; Kameswara Rao, N (IOP Publishing, 2021-12-20)
    We present the far-UV (FUV) photometry of images acquired with UVIT on AstroSat to probe the horizontal branch (HB) population of the Galactic globular cluster NGC 2298. UV-optical color–magnitude diagrams (CMDs) are ...
  • Chemical Compositions of Four Metal-poor Giant Stars 
    Giridhar, S; Lambert, D. L; Gonzalez, G; Pandey, G (University of Chicago Press, 2001-05)
    We present the chemical compositions of four K giants (CS 22877-1, CS 22166-16, CS 22169-35, and BS 16085-0050) that have [Fe/H] in the range -2.4 to -3.1. Metal-poor stars with [Fe/H]<-2.5 are known to exhibit considerable ...
  • Detection of fluorine in hot extreme helium stars 
    Bhowmick, A; Pandey, G; Lambert, D. L (IOP Publishing, 2020-03-01)
    The main objective of this paper is to explore abundances of fluorine in hot Extreme Helium Stars (EHes). Overabundance of fluorine is a chara cteristic feature for cool EHes and R Coronae Borealis (RCB) stars and ...
  • The development of HISPEC for Keck and MODHIS for TMT: science cases and predicted sensitivities 
    Konopacky, Quinn M; Baker, Ashley D; Mawet, Dimitri; Fitzgerald, Michael P; Jovanovic, Nemanja; Beichman, Charles; Ruane, Garreth; Bertz, Rob; Terada, Hiroshi; Dekany, Richard; Lingvay, Larry; Kassis, Marc; Anderson, David; Tamura, Motohide; Benneke, Bjorn; Beatty, Thomas; Do, Tuan; Nishiyama, Shogo; Plavchan, Peter; Wang, Jason; Wang, Ji; Burgasser, Adam; Ruffio, Jean-Baptiste; Zhang, Huihao; Brown, Aaron; Fucik, Jason; Gibbs, Aidan; Gibson, Rose; Halverson, Sam; Johnson, Christopher; Karkar, Sonia; Kotani, Takayuki; Kress, Evan; Leifer, Stephanie; Magnone, Kenneth; Maire, Jerome; Pahuja, Rishi; Porter, Michael; Roberts, Mitsuko; Sappey, Ben; Thorne, Jim; Wang, Eric; Artigau, Etienne; Blake, Geoffrey A; Canalizo, Gabriela; Chen, Guo; Doppmann, Greg; Doyon, Rene; Dressing, Courtney; Fang, Min; Greene, Thomas; Herczeg, Greg; Hillenbrand, Lynne; Howard, Andrew; Kane, Stephen; Kataria, Tiffany; Kempton, Eliza; Knutson, Heather; Lafrenière, David; Liu, Chao; Metchev, Stanimir; Millar-Blanchaer, Max; Narita, Norio; Pandey, G; Rajaguru, S. P; Robertson, Paul; Salyk, Colette; Sato, Bun’ei; Schlawin, Evertt; Sengupta, S; Sivarani, T; Skidmore, Warren; Vasisht, Gautam; Yasui, Chikako; Zhang, Hui (SPIE-The International Society for Optical Engineering, 2023-10)
    HISPEC is a new, high-resolution near-infrared spectrograph being designed for the W.M. Keck II telescope. By offering single-shot, R 100,000 spectroscopy between 0.98 – 2.5 µm, HISPEC will enable spectroscopy of transiting ...
  • The discovery of fluorine in cool extreme helium stars 
    Pandey, G (The University of Chicago Press, 2006-08-21)
    Neutral fluorine (F I) lines are identified in the optical spectra of cool extreme helium (EHe) stars. These are the first F I lines identified in a star's spectrum, and they provide the first measurement of fluorine ...
  • Discovery of Relatively Hydrogen-poor Giants in the Galactic Globular Cluster omega Centauri 
    Hema, B. P; Pandey, G (IOP Publishing, 2014-09-10)
    In this Letter, the results of our low-resolution spectroscopic survey for identifying hydrogen-deficient stars in the red giant sample of the globular cluster ω Cen are reported. Spectral analyses were carried out on the ...
  • Early time optical spectroscopy of supernova SN 1998S 
    Anupama, G. C; Sivarani, T; Pandey, G (EDP Sciences, 2001-02)
    We present medium-resolution optical spectra of the type II supernova SN 1998S obtained during the pre-maximum, maximum and early decline phases. The early decline spectra show complex Balmer line profiles: a narrow P-Cygni ...
  • The emission-line spectrum of the hot R Coronae Borealis star MV SGR 
    Pandey, G; Kameswara Rao, N; Lambert, D. L (Royal Astronomical Society, 1996-10)
    Spectra of MV Sgr obtained at CTIO in 1992 May show many emission lines in the red. Most of the emission lines show two components with a minimum centred at the stellar velocity. Species represented include H, HeI, TiII ...
  • Fluorine detection in hot extreme helium stars 
    Bhowmick, A; Pandey, G; Lambert, D. L (Springer, 2020-12)
    The origin and evolution of hydrogen-deficient stars are not yet adequately understood. Their chemical peculiarities, along with hydrogen-deficiency, makes them stand out from the rest and sheds light on their possible ...
  • Fluorine in R Coronae Borealis Stars 
    Pandey, G; Lambert, D. L; Kameswara Rao, N (Astronomical Society of the Pacific, 2008)
    Neutral fluorine lines are identified in the optical spectra of several R Coronae Borealis stars (RCBs) at maximum light. These lines provide the first measurement of the fluorine abundance in these stars. Fluorine is ...
  • Fluorine in R Coronae Borealis Stars 
    Pandey, G; Lambert, D. L; Kameswara Rao, N (University of Chicago Press, 2008-02)
    Neutral fluorine (F i) lines are identified in the optical spectra of several R Coronae Borealis stars (RCBs) at maximum light. These lines provide the first measurement of the fluorine abundance in these stars. Fluorine ...
  • The galactic R coronae borealis stars and the final he-shell flash object V4334Sgr (Sakurai’s object): a comparison 
    Hema, B. P; Pandey, G; Lambert, D. L (Proceedings of Science, 2012-08)
    The high resolution optical spectra of H-deficient stars, R Coronae Borealis stars and H-deficient carbon stars are analyzed by synthesizing the C2 Swan bands (0,1), (0,0), and (1,0) using our detailed line-list and ...
  • The Galactic R Coronae Borealis Stars: The C2 Swan Bands, the Carbon Problem, and the 12C/13C Ratio 
    Hema, B. P; Pandey, G; Lambert, D. L (IOP Publishing, 2012-03-10)
    Observed spectra of R Coronae Borealis (RCB) and hydrogen-deficient carbon (HdC) stars are analyzed by synthesizing the C2 Swan bands (1, 0), (0, 0), and (0, 1) using our detailed line list and the Uppsala model atmospheres. ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS) – I. FUV–optical colour–magnitude diagrams for eight globular clusters 
    Sahu, Snehalata; Subramaniam, A; Singh, Gaurav; Yadav, Ramakant; Valcarce, Aldo R; Choudhury, Samyaday; Sharmila Rani; Deepthi, S. Prabhu; Chung, Chul; Cote, Patrick; Leigh, Nathan; Geller, Aaron M; Chatterjee, Sourav; Kameswara Rao, N; Bandyopadhyay, Avrajit; Shara, Michael; Dalessandro, Emanuele; Pandey, G; Postma, Joesph E; Hutchings, John; Simunovic, Mirko; Stetson, Peter B; Sivarani, T; Puzia, Thomas; Sohn, Young-Jong (Oxford University Press on behalf of the Royal Astronomical Society, 2022-07)
    We present the first results of eight globular clusters (GCs) from the AstroSat/UVIT Legacy Survey programme GlobULeS based on the observations carried out in two far-ultraviolet (FUV) filters (F148W and F169M). The ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS). III. Omega Centauri in Far-ultraviolet 
    Deepthi, S. Prabhu; Subramaniam, A; Sahu, Snehalata; Chung, Chul; Leigh, Nathan W. C; Dalessandro, Emanuele; Chatterjee, Sourav; Kameswara Rao, N; Shara, Michael; Cote, Patrick; Choudhury, Samyaday; Pandey, G; Valcarce, Aldo A. R; Singh, G; Postma, Joesph E; Sharmila Rani; Bandyopadhyay, Avrajit; Geller, Aaron M; Hutchings, John; Puzia, Thomas; Simunovic, Mirko; Sohn, Young-Jong; Sivarani, T; Yadav, Ramakant Singh (American Astronomical Society, 2022-11-10)
    We present the first comprehensive study of the most massive globular cluster, Omega Centauri, in the farultraviolet (FUV), extending from the center to ∼28% of the tidal radius using the Ultraviolet Imaging Telescope on ...

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