RESEARCH PROJECTS
The Course of My Career
EXOPLANET DETECTION AND CHARACTERISATION
Sept'20 - Present
Radial velocity (RV) measurements have been widely used for the detection of exoplanets. For active stars, the RV information is contaminated by the intrinsic magnetic activity of the host star, by modifying the shape or position of stellar spectral lines. Low mass and/or long period planets induce RV semi-amplitudes similar to or smaller than those produced by stellar activity. Consequently, differentiating between a signal caused by stellar activity and a planet becomes more challenging, especially for the low-mass Earth-like exoplanets.
A new algorithm, SCALPELS (Collier Cameron et al. 2021), has been developed to separate RV Doppler shifts caused by the planets from the apparent RV variations caused by the spectral line-shape variability caused by stellar activity.
In this project, we explore the potential of this approach combined with and validated using several advanced data-driven techniques in mitigating the effects of the stellar variability in the RV data of active Sun-like stars. This approach considers the contributions of all additional planets whose existence may not be established conclusively, but whose RV variations influence the mass determination of the known transiting planet(s). For transiting planets, such mass determinations also reveal the density, and hence bulk composition, of the planet.
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Extending the applicability of this signal-separation technique to the bright Rocky-Planet Search targets is the current project in progress. The outcomes are likely to include significant improvements in the mass determinations of known planets, and discoveries of new low-mass planets whose velocity signals were previously below the detection threshold.
VARIABLE STARS INÂ INTERMEDIATE-AGE OPEN CLUSTER NGC 559.
Aug'19 - Mar'20
Time series V-band photometric observations on 40 nights taken over more than 3 yr with three different telescopes are analysed to search for variable stars in the cluster. The data was investigated for the periodicity analysis and 70 variable stars have been revealed, including 67 periodic variables in the target field, all of them were newly discovered. These variable stars have periodicity between 3 h to 41 d and their brightness ranges from V = 10.9 to 19.3 mag.
PHOTOMETRIC, KINEMATIC, VARIABILITY STUDY IN YOUNG OPEN CLUSTER NGC 1960
Aug'18Â - Jun'19
A comprehensive photometric analysis of a young open cluster NGC 1960 (= M36) along with the long-term variability study of this cluster. Based on the kinematic data of Gaia DR2, the membership probabilities of 3871 stars are ascertained in the cluster field among which 262 stars are found to be cluster members.This work also presents first high-precision variability survey in the central 13×13 arcmin region of the cluster. The V-band photometric data accumulated on 43 nights reveals 76 variable stars among which 72 are periodic variables.
TEMPERATURE EFFECTS OF SUNSPOT CYCLES AND PROPOSAL OF ‘MINI ICE AGE’.
Jul'16 - Mar'17
Using the data from NASA Space Marshall Flight Center data base and a formulation, the relative sunspot numbers from AD.1755 (312 years) have plotted and analyzed the decaying trend since 21st cycle. The implications of enfeebled solar activities and its effects on Earth’s climate have been studied and an attempt has been made to validate a proposed prediction of ‘ Mini Ice Age ’ that is supposed to happen during the 26th solar cycle (2030-2040), if this weakened solar activity trend continues.