116 citations · 602 across the 23 of their papers we have counts for
23 papers
Atmospheric escape from exoplanets: recent observations and theoretical models
Gopal Hazra
The review aims to give an overview of atmospheric escape processes from exoplanets. I briefly discuss the physics of various escape processes responsible for atmospheric escape ac…
Magnetic interaction of stellar coronal mass ejections with close-in exoplanets: implication on planetary mass loss and Ly- transits
Gopal Hazra, Aline A. Vidotto, Stephen Carolan +2
Coronal Mass Ejections (CMEs) erupting from the host star are expected to have effects on the atmospheric erosion processes of the orbiting planets. For planets with a magnetospher…
Mean field models of flux transport dynamo and meridional circulation in the Sun and stars
Gopal Hazra, Dibyendu Nandy, Leonid Kitchatinov +1
The most widely accepted model of the solar cycle is the flux transport dynamo model. This model evolved out of the traditional dynamo model which was first developed at a tim…
Atmospheric mass loss and stellar wind effects in young and old systems II: Is TOI-942 the past of TOI-421 system?
Daria Kubyshkina, Aline A. Vidotto, Carolina Villarreal D'Angelo +3
The two planetary systems TOI-942 and TOI-421 share many similar characteristics, apart from their ages (50~Myr and 9~Gyr). Each of the stars hosts two sub-Neptune-like planets at…
Atmospheric mass loss and stellar wind effects in young and old systems I: comparative 3D study of TOI-942 and TOI-421 systems
Daria Kubyshkina, Aline A. Vidotto, Carolina Villarreal D'Angelo +3
At young ages, when radiation from the host star is high, and the planet is hot and inflated after formation, planetary atmospheric mass loss can be extremely strong compared to ol…
The impact of coronal mass ejections and flares on the atmosphere of the hot Jupiter HD189733b
Gopal Hazra, Aline A. Vidotto, Stephen Carolan +2
High-energy stellar irradiation can photoevaporate planetary atmospheres, which can be observed in spectroscopic transits of hydrogen lines. For the exoplanet HD189733b, multiple o…
The Effects of Magnetic Fields on Observational Signatures of Atmospheric Escape in Exoplanets: Double Tail Structures
S. Carolan, A. A. Vidotto, G. Hazra +2
Using 3D radiative MHD simulations and Lyman- transit calculations, we investigate the effect of magnetic fields on the observational signatures of atmospheric escape in exoplan…
GJ 436b and the stellar wind interaction: simulations constraints using Ly and H transits
C. Villarreal D'Angelo, A. A. Vidotto, A. Esquivel +2
The GJ 436 planetary system is an extraordinary system. The Neptune-size planet that orbits the M3 dwarf revealed in the Ly line an extended neutral hydrogen atmosphere. This ma…
Effects of the stellar wind on the Ly-alpha transit of close-in planets
S. Carolan, A. A. Vidotto, C. Villarreal D'Angelo +1
We use 3D hydrodynamics simulations followed by synthetic line profile calculations to examine the effect increasing the strength of the stellar wind has on observed Ly- transit…
Recent advances in the 3D kinematic Babcock-Leighton solar dynamo modeling
Gopal Hazra
In this review, we explain recent progress made in the Babcock-Leighton dynamo models for the Sun, which have been most successful to explain various properties of the solar cycle.…
The dichotomy of atmospheric escape in AU Mic b
S. Carolan, A. A. Vidotto, P. Plavchan +2
Here, we study the dichotomy of the escaping atmosphere of the newly discovered close-in exoplanet AU Mic b. On one hand, the high EUV stellar flux is expected to cause a strong at…
Influence of the Sun-like magnetic cycle on exoplanetary atmospheric escape
Gopal Hazra, Aline A. Vidotto, Carolina Villarreal D'Angelo
Stellar high-energy radiation (X-ray and extreme ultraviolet, XUV) drives atmospheric escape in close-in exoplanets. Given that stellar irradiation depends on the stellar magnetism…
Exploring cycle period and parity of stellar magnetic activity with dynamo modeling
Gopal Hazra, Jie Jiang, Bidya Binay Karak +1
Observations of chromospheric and coronal emissions from various solar-type stars show that the stellar magnetic activity varies with the rotation rates of the stars. The faster th…
A New Formula for Predicting Solar Cycles
Gopal Hazra, Arnab Rai Choudhuri
A new formula for predicting solar cycles based on the current theoretical understanding of the solar cycle from flux transport dynamo is presented. Two important processes---fluct…
Explaining the variation of the meridional circulation with the solar cycle
Gopal Hazra, Arnab Rai Choudhuri
The meridional circulation of the Sun is observationally found to vary with the solar cycle, becoming slower during the solar maxima. We explain this by constructing a theoretical…
Understanding the behavior of the Sun's large scale magnetic field and its relation with the meridional flow
Gopal Hazra
In this thesis, various studies are performed leading to better understanding of the 11-year solar cycle and its theoretical modeling with the flux transport dynamo model. Although…
Incorporating Surface Convection into a 3D Babcock-Leighton Solar Dynamo Model
Gopal Hazra, Mark Miesch
The observed convective flows on the photosphere (e.g., supergranulation, granulation) play a key role in the Babcock-Leighton (BL) process to generate large-scale polar fields fro…
A theoretical model of the variation of the meridional circulation with the solar cycle
Gopal Hazra, Arnab Rai Choudhuri
Observations of the meridional circulation of the Sun, which plays a key role in the operation of the solar dynamo, indicate that its speed varies with the solar cycle, becoming fa…
A theoretical study of the build-up of the Sun's polar magnetic field by using a 3D kinematic dynamo model
Gopal Hazra, Arnab Rai Choudhuri, Mark S. Miesch
We develop a three-dimensional kinematic self-sustaining model of the solar dynamo in which the poloidal field generation is from tilted bipolar sunspot pairs placed on the solar s…
The treatment of magnetic buoyancy in flux transport dynamo models
Arnab Rai Choudhuri, Gopal Hazra
One important ingredient of flux transport dynamo models is the rise of the toroidal magnetic field through the convection zone due to magnetic buoyancy to produce bipolar sunspots…
Correlation between Decay Rate and Amplitude of Solar Cycles as Revealed from Observations and Dynamo Theory
Gopal Hazra, Bidya Binay Karak, Dipankar Banerjee +1
Using different proxies of solar activity, we have studied the following features of solar cycle. (i) A linear correlation between the amplitude of cycle and its decay rate, (ii) a…
Is a deep one-cell meridional circulation essential for the flux transport Solar Dynamo?
Gopal Hazra, Bidya Binay Karak, Arnab Rai Choudhuri
The solar activity cycle is successfully modeled by the flux transport dynamo, in which the meridional circulation of the Sun plays an important role. Most of the kinematic dynamo…
Boundary perturbations and the Helmholtz equation in three dimensions
S. Panda, G. Hazra
We propose an analytic perturbative scheme for determining the eigenvalues of the Helmholtz equation, , in three dimensions with an arbitrary boundary where…