Research Highlights | Subhajeet Karmakar

MY RESEARCH HIGHLIGHTS

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...

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...

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Subhajeet Karmakar

MY RESEARCH HIGHLIGHTS

Quasi-Periodic Pulsation in the decay phase of a flare on AB Dor

From Swift BAT+XRT spectra, and Iron Kα fluorescence line estimating flare location

Brightest, hottest and shortest-duration X-ray Superflare ever observed on CC Eri using Swift

Evolution of Temperature, emission measure, and abundances during flaring events on M-dwarf binary

Longest Duration X-ray Superflares ever observed on EQ Peg with AstroSat satellite

X-ray flares on CC Eri

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?

Variation of stellar spottedness with surface-temperature on active solar-type stars

Starspots: Observation of photosphere, chromosphere, vs. corona

Starspot evolution and flip-flop cycle from long-term photometry on a K-dwarf

Starspot Evolution on stellar surface on a F-type star constructed from Kepler observations

F-type ultra-fast rotator KIC 6791060

Binding energy & binary separation vs. stellar mass of VLM binaries

Discovery of companion to Very Low Mass binary using Very Large Telescope

4. Polarisation from a star: Intrinsic or Extrinsic?

Polarization vs Color for FGK dwarfs

Broad-band linear polarization in late-type active FGK dwarfs

5. Surface Differential Rotation of stars: how to measure it?

Solar-type Surface Differential Rotation on a K-dwarf LO Peg

Surface Differential Rotation & Butterfly Diagram

6. Massive Stars: Understanding Wind-properties

XMM-Newton & Swift Phase-folded light curve of WR 25

Phase-resolved Spectroscopy of Massive stars

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MY RESEARCH HIGHLIGHTS

Quasi-Periodic Pulsation in the decay phase of a flare on AB Dor

From Swift BAT+XRT spectra, and Iron Kα fluorescence line estimating flare location

Brightest, hottest and shortest-duration X-ray Superflare ever observed on CC Eri using Swift

Evolution of Temperature, emission measure, and abundances during flaring events on M-dwarf binary

Longest Duration X-ray Superflares ever observed on EQ Peg with AstroSat satellite

X-ray flares on CC Eri

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?

Variation of stellar spottedness with surface-temperature on active solar-type stars

Starspots: Observation of photosphere, chromosphere, vs. corona

Starspot evolution and flip-flop cycle from long-term photometry on a K-dwarf

Starspot Evolution on stellar surface on a F-type star constructed from Kepler observations

F-type ultra-fast rotator KIC 6791060

Binding energy & binary separation vs. stellar mass of VLM binaries

​Discovery of companion to Very Low Mass binary using Very Large Telescope

4. Polarisation from a star: Intrinsic or Extrinsic?

Polarization vs Color for FGK dwarfs

Broad-band linear polarization in late-type active FGK dwarfs

5. Surface Differential Rotation of stars: how to measure it?

Solar-type Surface Differential Rotation on a K-dwarf LO Peg

Surface Differential Rotation & Butterfly Diagram

6. Massive Stars: Understanding Wind-properties

XMM-Newton & Swift Phase-folded light curve of WR 25

Phase-resolved Spectroscopy of Massive stars

Discovery of companion to Very Low Mass binary using Very Large Telescope