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Browsing by Author "Sengupta, S"

Browsing by Author "Sengupta, S"

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  • Detecting exomoons around self-luminous giant exoplanets through polarization 
    Sengupta, S; Marley, M. S (IOP Publishing, 2016-06-20)
    Many of the directly imaged self-luminous gas-giant exoplanets have been found to have cloudy atmospheres. Scattering of the emergent thermal radiation from these planets by the dust grains in their atmospheres should ...
  • Detection of Polarization due to Cloud Bands in the Nearby Luhman 16 Brown Dwarf Binary 
    Millar-Blanchaer, M. A; Girard, J. H; Karalidi, T; Marley, M. S; van Holstein, R. G; Sengupta, S; Mawet, Dimitri; Kataria, Tiffany; Jos de Boer, F. S (IOP Publishing, 2020-05-01)
    Brown dwarfs exhibit patchy or spatially varying banded cloud structures that are inferred through photometric and spectroscopic variability modeling techniques. However, these methods are insensitive to rotationally ...
  • 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 ...
  • Effect of Multiple Scattering on the Transmission Spectra and the Polarization Phase Curves for Earth-like Exoplanets 
    Singla, Manika; Chakrabarty, Aritra; Sengupta, S (American Astronomical Society, 2023-02-20)
    It is the most appropriate time to characterize the Earth-like exoplanets in order to detect biosignature beyond the Earth because such exoplanets will be the prime targets of big-budget missions like JWST, Roman ...
  • Effects of dust scattering in expanding spherical nebulae 
    Srinivasa Rao, M; Sengupta, S (Elsevier B. V., 2004-03)
    The mean intensity of planetary nebulae with an expanding atmosphere is modeled by considering dusty and dust-free atmospheres. The bulk matter density is determined from the adopted velocity field through the equation of ...
  • Effects of thermal emission on the transmission spectra of hot Jupiters 
    Chakrabarty, Aritra; Sengupta, S (IOP Publishing, 2020-07-20)
    The atmosphere on the dayside of a highly irradiated close-in gas giant (also known as a hot Jupiter) absorbs a significant part of the incident stellar radiation, which again gets re-emitted in the infrared wavelengths ...
  • Explaining the Observed Polarization from Brown Dwarfs by Single Dust Scattering 
    Sengupta, S (The American Astronomical Society, 2003-03)
    Recent observation of linear optical polarization from brown dwarfs confirms the dust hypothesis in the atmospheres of brown dwarfs with effective temperature higher than 1400 K. The observed polarization could arise because ...
  • General Relativistic Effects on the Induced Electric Field Exterior to Pulsars 
    Sengupta, S (The American Astronomical Society, 1995-08)
    The importance of general relativity to the induced electric field exterior to pulsars has been investigated by assuming aligned vacuum and nonvacuum magnetosphere models. For this purpose, the stationary and axisymmetric ...
  • General Relativistic Effects on the Ohmic Decay of Crustal Magnetic Fields in Neutron Stars 
    Sengupta, S (The American Astronomical Society, 1997-04)
    The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating the effect of spacetime curvature produced by the intense gravitational field of the star. It is shown that the ...
  • Generic models for disk-resolved and disk-integrated phase-dependent linear polarization of light reflected from exoplanets 
    Chakrabarty, Aritra; Sengupta, S (IOP Publishing, 2021-08-20)
    Similar to the case of solar system planets, reflected starlight from exoplanets is expected to be polarized due to atmospheric scattering, and the net disk-integrated polarization should be nonzero owing to the asymmetrical ...
  • High-resolution Infrared Spectrograph for Exoplanet Characterization with the Keck and Thirty Meter Telescopes 
    Mawet, Dimitri; Fitzgerald, Michael; Konopacky, Quinn; Beichman, Charles; Jovanovic, Nemanja; Dekany, Richard; Hover, David; Chisholm, Eric; Ciardi, David; Artigau, Etienne; Banyal, Ravinder; Beatty, Thomas; Benneke, Bjorn; Blake, Geoffrey A; Burgasser, Adam; Canalizo, Gabriela; Chen, Guo; Do, Tuan; Doppmann, Greg; Doyon, Rene; Dressing, Courtney; Fang, Min; Greene, Thomas; Hillenbrand, Lynne; Howard, Andrew; Kane, Stephen; Kataria, Tiffany; Kempton, Eliza; Knutson, Heather; Kotani, Takayuki; Lafreniere, David; Liu, Chao; Nishiyama, Shogo; Pandey, G; Plavchan, Peter; Prato, Lisa; Rajaguru, S. P; Robertson, Paul; Salyk, Colette; Sato, Bun’ei; Schlawin, Everett; Sengupta, S; Sivarani, T; Skidmore, Warren; Tamura, Motohide; Terada, Hiroshi; Vasisht, Gautam; Wang, Ji; Zhang, Hui (American Astronomical Society, 2019-09)
    HISPEC (High-resolution Infrared Spectrograph for Exoplanet Characterization) is a proposed diffractionlimited spectrograph for the W.M. Keck Observatory, and a pathfinder for the MODHIS facility project (Multi-Object ...
  • Joule Heating in Neutron Stars under Strong Gravitation 
    Sengupta, S (The American Astronomical Society, 2000-11)
    Considering Joule heating caused by the dissipation of the magnetic field in the neutron star crust to be an efficient mechanism in maintaining a relatively high surface temperature in very old neutron stars, the role of ...
  • Line formation in the Atmosphere of brown dwarf Gliese 229B : CH_4 at 2.3 mu m 
    Sengupta, S; Krishan, V (European Southern Observatory, 2000-06)
    We investigate the formation of methane line at 2.3 μm in Brown Dwarf Gliese 229B. Two sets of model parameters with (a) T_eff=940 K and log (g) =5.0, (b) T_eff=1030 K and log (g)=5.5 are adopted both of which provide ...
  • Multiband transit follow-up observations of five hot Jupiters with critical noise treatments: improved physical properties 
    Saha, Suman; Chakrabarty, Aritra; Sengupta, S (IOP Publishing, 2021-07-01)
    The most challenging limitation in transit photometry arises from the noises in the photometric signal. In particular, the ground-based telescopes are heavily affected by the noise due to perturbation in the Earth’s ...
  • Multiple scattering polarization of substellar-mass objects: T dwarfs 
    Sengupta, S; Marley, M. S (American Astronomical Society, 2009-12-10)
    While there have been multiple observational programs aimed at detecting linear polarization of optical radiation emitted by ultracool dwarfs, there has been comparatively less rigorous theoretical analysis of the problem. ...
  • Multiple scattering polarization – Application of Chandrasekhar’s formalisms to the atmosphere of brown dwarfs and extrasolar planets 
    Sengupta, S; Marley, Mark S (Indian Academy of Science, 2011-07)
    Chandrasekhar’s formalisms for the transfer of polarized radiation are used to explain the observed dust scattering polarization of brown dwarfs in the optical band. Model polarization profiles for hot and young directly ...
  • New models of reflection spectra for terrestrial exoplanets: Present and prebiotic Earth orbiting around stars of different spectral types 
    Singla, Manika; Sengupta, S (Elsevier B.V., 2023-08)
    In order to recognize a habitable exoplanet from future observed spectra, we present new model reflected spectra and geometric albedo for modern and prebiotic (∼3.9 Ga) Earth-like exoplanets orbiting within the habitable ...
  • A Newtonian interpretation of the parameter "a" associated with the Kerr metric 
    Sengupta, S (World Scientific Publishers, 1996-06)
    The parameter "a" associated with the Kerr metric has been used to determine the rotationally induced quadrapole electric field outside a rotating massive object with external dipole magnetic field. A comparison of the ...
  • Observation of R-Band Variability of L Dwarfs 
    Maiti, M; Sengupta, S; Parihar, P. S; Anupama, G. C (University of Chicago Press, 2005-02)
    We report, for the first time, photometric variability of L dwarfs in the R band. Out of three L1 dwarfs (2MASS 1300+19, 2MASS 1439+19, and 2MASS 1658+70) observed, we have detected R-band variability in 2MASS 1300+19 and ...
  • Observed polarization of brown dwarfs suggests low surface gravity 
    Sengupta, S; Marley, M. S (IOP Publishing, 2010-10-20)
    Light scattering by atmospheric dust particles is responsible for the polarization observed in some L dwarfs. Whether this polarization arises from an inhomogeneous distribution of dust across the disk or an oblate shape ...

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