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Showing 1 to 15 of 15 for “"brown dwarfs"”.
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The Formation of Brown Dwarfs
… of twelve very young bona fide and candidate brown dwarfs in the ChaI star forming cloud (ChaHa1-12) was studied observationally in terms of their kinematic properties, the occurrence of multiple systems among them as well as their rotational characteristics. Based on high-resolution spectra …
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The Theory of the Formation of Brown Dwarfs
… and its implications on the ejection model as Brown Dwarf formation scenario. A modified chain-regularization scheme is used to integrate the equations of motion, that also allows for mass changes over time as well as for momentum transfer from the accreted gas mass onto the bodies. We …
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A theoretical study of stellart pulsations in young brown dwarfs
… phenomenon of ‘stellar pulsations’ in young brown dwarfs by the seminal study of Palla and Baraffe (2005) (PB05, thereafter). The PB05 study presents results of a non-adiabatic linear stability analysis showing that young brown dwarfs should become pulsationally unstable during the deuterium …
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Coronagraphic data post-processing using projections on instrumental modes
… of over a dozen exoplanets and a multitude of brown dwarfs and circumstellar disks. Despite advances in coronagraphy and wavefront control, high contrast observations are still plagued by residual wavefront aberrations. Post-processing techniques can provide an additional boost in separating …
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The migration of giant planets in massive protoplanetary discs
… of these planets accrete enough mass to become brown dwarfs. This could explain the observations of giant planets at wide orbital radii from the host star.
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Thermal and Radiative Properties of Exoplanet Atmospheres Across the Mass Range
… masses and irradiation conditions, from isolated brown dwarfs to rocky exoplanets. I begin by investigating important considerations for the atmospheric retrieval of isolated brown dwarfs. These objects provide remarkable laboratories for understanding atmospheric physics in the low-irradiation …
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Dynamics and evolution of dense stellar systems
… which could represent free-floating planets or brown dwarfs, are predominantly lost from the cluster, as expected from simple analytical arguments, but may remain in the halo in larger numbers than expected. Using a recent null detection of planetary-mass microlensing events in M22, I find an …
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The Initial Mass Function of the Orion Nebula Cluster from Near-Infrared Photometry
… of the Orion Nebula Cluster (ONC) down to the Brown Dwarfs (BDs) regime, using ground-based Near-Infrared (NIR) photometric observations. The data taken in the framework of the Hubble Space Telescope (HST) Treasury Program on the ONC have been obtained with the wide-field imager Infrared Side …
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Weather on Substellar Worlds: A Study of Clouds, Variability and Binarity at the L/T Transition
A study of clouds and variability in brown dwarf atmospheres is presented, with a focus on understanding the mechanism by which condensate clouds are dissipated at the transition between L and T spectral types. The results of a large J-band variability survey of over 60 mid-L to T dwarfs, and …
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Gravitational Lensing and the Maximum Number of Images
… to find and constrain the mass of planets or brown dwarfs in multiple star systems. For the case of more realistic mass distributions, we prove that when a point-mass is replaced with a distributed lens that does not overlap with existing images or lensing objects, an additional image is …
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High Resolution Spectra of Carbon Monoxide, Propane and Ammonia for Atmospheric Remote Sensing
… stars and cool sub-stellar objects known as brown dwarfs. The spectra of propane and ammonia provide the highest resolution and most complete experimental study of these gases in their respective spectral regions at elevated temperatures. Detection of ammonia in an exoplanet or detection of …
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Monte-Carlo simulations of globular cluster dynamics
… of very-low-mass (m < 0.1M.) objects, such as brown dwarfs or planets, in the outer halos of globular clusters, even though they are quickly lost from the central, denser regions. This is contrary to the common belief that globular clusters are devoid of such low-mass objects. We have also …
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Using fusion-product spectroscopy to study inertial fusion implosions, stopping power, and astrophysical nucleosynthesis at OMEGA and the NIF
… reaction is relevant to energy generation in brown dwarfs, protostars, and to production of ³He during the Big Bang.
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Chemical Characterisations of Exoplanetary Atmospheres
… method for directly-imaged exoplanets and brown dwarfs. The retrieval structure is applied to the most iconic imaged system, HR 8799, composed of four giant companions. We find the presence of water vapour at high confidence (>5-sigma) in all four atmospheres and strong evidence for carbon …
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Constraining the Initial Conditions and Final Outcomes of Accretion Processes around Young Stars and Supermassive Black Holes
… are similar to the spectra of older more massive brown dwarfs at the same temperature, in contrast to objects at 1000 K that exhibit distinct L-band SEDs. The oldest object in my sample of young companions, 50 My old CD-35 2722 B, appears redder than field dwarfs with similar spectral type based …