22 citations · 91 across the 14 of their papers we have counts for
17 papers
Quiescent and flaring states of three active stars: V834 Tau, LQ Hya, and BY Dra
Gurpreet Singh, Jeewan C. Pandey, Subhajeet Karmakar
We present a detailed X-ray study of the quiescent and flaring coronae of three active main-sequence K-type stars, V834 Tau, LQ Hya, and BY Dra, using \textit{XMM-Newton} observati…
The Need for Ultra High Resolution X-ray Imaging
Kimberly A. Weaver, Jenna M. Cann, Ryan Pfeifle +20
This paper discusses the broad science case for obtaining milliarcsecond to microarcsecond astronomical imaging resolution in the soft to medium-energy X-ray band (~0.5 to ~8 keV).…
AstroSat investigation of X-ray flares on two active K-M systems: CC Eri and AB Dor
Subhajeet Karmakar, Jeewan C. Pandey, Nikita Rawat +2
We present an X-ray and UV investigation of five X-ray flares detected on two active systems, CC Eri and AB Dor, using the AstroSat observatory. The peak X-ray luminosities of the…
Near-UV and optical spectroscopic investigation of late-type stars from MIRA/Oliver Observing Station
Subhajeet Karmakar, Avrajit Bandyopadhyay, Wm. Bruce Weaver +4
Late-type stars are the most abundant in the galactic stellar population. These stars, with a similar internal structure to the Sun, are expected to have solar-like atmospheres. In…
Investigation of very low mass binaries using VLT/NaCo
Subhajeet Karmakar, Arvind Singh Rajpurohit, Derek Homeier
Context: Most stars in the galactic stellar population are low-mass stars. Very low-mass (VLM) stars are a subset of the low-mass stars typically defined in terms of the stellar ma…
Swift and XMM-Newton observations of an RS CVn type eclipsing binary SZ Psc: Superflare and coronal properties
Subhajeet Karmakar, Sachindra Naik, Jeewan C. Pandey +1
We present an in-depth study of a large and long duration (1.3 days) X-ray flare observed on an RS CVn type eclipsing binary system SZ Psc using observations from Swift observat…
AstroSat observations of long-duration X-ray superflares on active M-dwarf binary EQ Peg
Subhajeet Karmakar, Sachindra Naik, Jeewan C. Pandey +1
We present a comprehensive study of three large long-duration flares detected on an active M-dwarf binary EQ Peg using the Soft X-Ray Telescope of the AstroSat observatory. The pea…
Coronae of an active fast rotator FR Cnc
Jeewan C. Pandey, Gurpreet Singh, Subhajeet Karmakar +4
We present the first detailed X-ray study and simultaneous optical observations of the active fast rotating star FR Cnc. The X-ray spectra are found to be explained by two-temperat…
Detection and characterisation of two VLM binaries: LP 1033-31 and LP 877-72
Subhajeet Karmakar, A. S. Rajpurohit, F. Allard +1
Using the high-resolution near-infrared adaptive optics imaging from the NaCo instrument at the Very Large Telescope, we report the discovery of a new binary companion to the M-dwa…
Magnetic activities on active solar-type stars
Subhajeet Karmakar, Jeewan C. Pandey, Sachindra Naik +2
We present results obtained from the studies of magnetic activities on four solar-type stars (F-type star KIC 6791060, K-type star LO Peg, and two M-type planet-hosting stars K2-33…
An F-type ultra-fast rotator KIC 6791060: Starspot modulation and Flares
Subhajeet Karmakar, Jeewan C. Pandey
Making use of the data obtained from Kepler satellite, we have analysed an F-type ultra-fast rotator KIC 6791060. We derive a rotational period of 0.343650.00004 d. Multiple p…
First Evidence of the Frequency Filtering of Magnetoacoustic Waves in the Flaring Star EK Dra
A. K. Srivastava, J. C. Pandey, Subhajeet Karmakar +7
Using the data obtained from XMM-Newton, we show the gradual evolution of two periodicities of ~4500 s and ~2200 s in the decay phase of the flare observed in a solar analog EK Dra…
X-Ray Superflares on CC Eri
Subhajeet Karmakar, J. C. Pandey, V. S. Airapetian +1
We present an in-depth study of two superflares (F1 and F2) detected on an active binary star CC Eridani by the Swift observatory. These superflares triggered the Burst Alert Teles…
LO Peg: surface differential rotation, flares, and spot-topographic evolution
Subhajeet Karmakar, J. C. Pandey, I. S. Savanov +8
Using the wealth of ~24 yr multiband data, we present an in-depth study of the star-spot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distri…
Broad-band linear polarization in late-type active dwarfs
Manoj K. Patel, Jeewan C. Pandey, Subhajeet Karmakar +2
We present recent polarimetric results of magnetically active late-type dwarfs. The polarization in these stars is found to be wavelength dependent, decreasing towards the longer w…
An X-ray flare from 47 Cas
Jeewan C Pandey, Subhajeet Karmakar
Using XMM-Newton observation, we investigate properties of a flare from the very active and poorly known stellar system 47 Cas. The luminosity at the peak of the flare was found to…
Phase-resolved XMM-Newton and swift observations of WR 25
J. C. Pandey, S. B. Pandey, Subhajeet Karmakar
We present an analysis of long-term X-ray and optical observations of the Wolf-Rayet binary WR 25. Using archival data from observations with the XMM-Newton and the Swift observato…