Quasi-Periodic Pulsation in the decay phase of a flare on AB Dor
Oscillation periods versus damping times of monotonously-decaying quasi-harmonic quasi-periodic pulsation (QPP) occurring the decay...
MY RESEARCH HIGHLIGHTS
From Swift BAT+XRT spectra, and Iron Kα fluorescence line estimating flare location
Modeling of 6.4 keV line flux for the seven time intervals during the decay of a flare on CC Eri. The solid horizontal lines show the...
Brightest, hottest and shortest-duration X-ray Superflare ever observed on CC Eri using Swift
The flare F1 triggered Swift’s Burst Alert Telescope (BAT) on 2008 October 16 UT 11:22:52 (=T01) during a preplanned spacecraft slew....
Evolution of Temperature, emission measure, and abundances during flaring events on M-dwarf binary
Evolution of spectral parameters of EQ Peg have been shown. These parameters have been estimated from time-resolved spectroscopy. From...
Longest Duration X-ray Superflares ever observed on EQ Peg with AstroSat satellite
The longest duration X-ray Superflares ever observed on EQ Peg with AstroSat satellite is shown here. In the top panel, the...
X-ray flares on CC Eri
Here is my second international talk in the splinter session of "Flares in time-domain surveys" in "Cool Stars 19" conference at Uppsala,...
1. X-ray flares & Superflares
2. Starspot Evolution & Rotational Modulation
3. Discovery of a binary companion to Very Low Mass star using VLT
Spottedness vs Flare number: Are they related?
In order to check whether the spottedness on the stellar surface is related to occurrence rate of flare, we plotted the distribution of...
Variation of stellar spottedness with surface-temperature on active solar-type stars
The spottedness (S) vs. stellar effective temperature (T_eff) plot for F–M type stars taken from the catalog of McQuillan et al. (2014)....
Starspots: Observation of photosphere, chromosphere, vs. corona
From top to bottom the X-ray, UV, and optical folded light curves are shown. Each folded light curve is binned at bin-size 0.1. The...
Starspot evolution and flip-flop cycle from long-term photometry on a K-dwarf
Parameters of K-dwarf LO Peg derived from modelling have been shown. From top to bottom – (a) V-band light curve of LO Peg (open...
Starspot Evolution on stellar surface on a F-type star constructed from Kepler observations
The F-type star KIC 6791060 was observed for four years from 13 December 2009 to 13 December 2013 by the Kepler satellite. The Kepler...
F-type ultra-fast rotator KIC 6791060
The 3-minute presentation I have given at the first Belgo-Indian Network for Astronomy & Astrophysics (BINA) Workshop in ARIES, Nainital,...
Binding energy & binary separation vs. stellar mass of VLM binaries
(a) System Binding Energy versus Total Mass (primary + secondary) and (b) Binary Separation versus Total Mass is shown. The newly...
Discovery of companion to Very Low Mass binary using Very Large Telescope
Using the Very Large Telescope (VLT) of European Southern Observatory (ESO, Chile) specifically the Nasmyth Adaptive Optics System (NAOS)...
4. Polarisation from a star: Intrinsic or Extrinsic?
Polarization vs Color for FGK dwarfs
The behaviour of degree of linear polarization P and (B − V) colour in B, V, R, and I bands is displayed in Fig. 5. The degree of...
Broad-band linear polarization in late-type active FGK dwarfs
Polarimetric observations of stars in the sample were obtained during the years 2010–2014 using ARIES Imaging Polarimeter (AIMPOL;...
5. Surface Differential Rotation of stars: how to measure it?
Solar-type Surface Differential Rotation on a K-dwarf LO Peg
Top panel of the above figure shows the V-band light curve (solid triangles) along with the mean magnitude of each season (open circles)....
Surface Differential Rotation & Butterfly Diagram
The above gif image shows how the star like the Sun show a butterfly pattern, and how it is helpful to study Surface Differential...
6. Massive Stars: Understanding Wind-properties
XMM-Newton & Swift Phase-folded light curve of WR 25
The X-ray light curves as observed from XMM-Newton (MOS) and Swift (XRT) in the total (0.5 - 10.0 keV), hard (2.0 - 10.0 keV) and soft...
Phase-resolved Spectroscopy of Massive stars
X-ray spectra of WR 25 as observed from MOS and PN detectors along with the best fit folded 2T vapec model at nine epochs. WR 25 was...