Gourav Banerjee

Gourav Banerjee
Christ University, Bangalore · Department of Physics

PhD scholar (stellar astrophysics), CHRIST (Deemed to be University), Bangalore
Studying major emission line features and long-term variability of classical Be stars using spectroscopy & photometry

About

16
Publications
891
Reads
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28
Citations
Introduction
My area of research is stellar spectroscopy, especially observational studies of emission-line stars like Classical Be (CBe) stars and rare stars in transition between PMS and MS phase. I am presently studying Galactic CBe stars in the optical regime to understand their long-term variability, i.e. their disc transient nature and V/R variations. Moreover, I am involved in the analysis of different spectral features exhibited by CBe star optical spectra located in different environments.
Additional affiliations
June 2019 - present
Christ University, Bangalore
Position
  • Researcher
Description
  • I study Galactic Classical Be stars using optical spectroscopy and am also involved in identifying other types of emission-line stars such as Classical Ae stars, TP candidates: stars in transition between PMS & MS phase.
Education
June 2017 - June 2019
Christ University, Bangalore
Field of study
  • Astrophysics
August 2011 - July 2012
M. P. Birla Institute of Fundamental Research
Field of study
  • Astronomy and Planetarium Science
August 2010 - July 2012
MIT, Manipal University
Field of study
  • Astronomy and Space Engineering

Publications

Publications (16)
Article
Full-text available
We present a follow-up study on the recent detection of two X-ray flaring events by MAXI/Gas Slit Camera observations in soft and hard X-rays from MAXI J0709–159 in the direction of HD 54786 (LY CMa), on 2022 January 25. The X-ray luminosity during the flare was around 10 ³⁷ erg s ⁻¹ (MAXI), which got reduced to 10 ³² erg s ⁻¹ (NuSTAR) after the fl...
Preprint
We present a follow-up study on the recent detection of two X-ray flaring events by MAXI/GSC observations in soft and hard X-rays from MAXI J0709-159 in the direction of HD 54786 (LY CMa), on 2022 January 25. The X-ray luminosity during the flare was around 10^(37) erg/s (MAXI), which got reduced to 10^(32) erg/s (NuSTAR) after the flare. We took l...
Article
Full-text available
Stars are not just useful in the pursuit of astronomy, their importance to us is fundamental. However, the true nature of stars remained a mystery for centuries. Then, through years of hard work we presently do have the tool using which we can actually study and understand the stars. That tool is spectroscopy. For the past few years, intense resear...
Article
Full-text available
Over time, pre-main-sequence (PMS) stars evolve into main-sequence (MS) stars. Stars evolving from PMS to MS phase is a significant subject of research that aims to better understand stellar phases and their properties. Existing literature shows a lack of study of stars in between PMS and MS phase. 'We focused on what belongs in the midst of these...
Preprint
We performed the slitless spectroscopic survey to identify Classical (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both H$\alpha$ in emission and IR excess, which confirm that they posse...
Article
Full-text available
We performed the slitless spectroscopic survey to identify classical Be (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both Ha in emission and IR excess, which confirm that they possess g...
Article
Full-text available
We performed the slitless spectroscopic survey to identify classical Be (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both H\(\alpha \) in emission and IR excess, which confirm that they...
Presentation
Full-text available
I have presented this talk, "Emission line stars in the transition phase from pre-main sequence to main sequence", at the 7th Regional Astronomers' Meeting through Google Meet Platform, which took place from 8th to 10th of September 2021. Under the sponsorship of IUCAA, Pune, India, it was organized by Mar Thoma College, Chungathara, Kerala, India,...
Article
Full-text available
Pre-main sequence (PMS) stars evolve into main sequence (MS) phase over a period of time. Interestingly, we found a scarcity of studies in existing literature that examines and attempts to better understand the stars in PMS to MS transition phase. The purpose of the present study is to detect such rare stars, which we named as ‘Transition Phase’ (T...
Preprint
Full-text available
Pre-main sequence (PMS) stars evolve into main sequence (MS) phase over a period of time. Interestingly, we found a scarcity of studies in existing literature that examines and attempts to better understand the stars in PMS to MS transition phase. The purpose of the present study is to detect such rare stars, which we named as 'Transition Phase' (T...
Article
Full-text available
We report the first systematic study to identify and characterize a sample of classical Ae stars in the Galaxy. The spectra of these stars were retrieved from the A-star catalog using the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) survey. We identified the emission-line stars in this catalog from which 159 are confirmed as c...
Preprint
Full-text available
We report the first systematic study to identify and characterize a sample of classical Ae stars in the Galaxy. The spectra of these stars were retrieved from the A-star catalog using the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) survey. We identified the emission-line stars in this catalog from which 159 are confirmed as c...
Preprint
Full-text available
In this study, we analyze the emission lines of different species present in 118 Galactic field classical Be stars in the wavelength range of 3800 - 9000 \AA. We re-estimated the extinction parameter (A$_V$) for our sample stars using the newly available data from Gaia DR2 and suggest that it is important to consider A$_V$ while measuring the Balme...
Article
Full-text available
In this study, we analyze the emission lines of different species present in 118 Galactic field classical Be stars in the wavelength range of 3800 - 9000 Å. We re-estimated the extinction parameter (AV) for our sample stars using the newly available data from Gaia DR2 and suggest that it is important to consider AV while measuring the Balmer decrem...
Presentation
Full-text available
I presented this talk titled "Optical Spectroscopy of Galactic Field Classical Be Stars" in the Regional Astronomers' Meeting-VI during July 9-10, 2020. It was held by the initiative of WMO College, Wayanad, Kerala, India through Google Meet Platform under the sponsorship of IUCAA, Pune, India.
Article
Full-text available
A popular level article providing fundamental idea about the properties of Be stars and what kind of research is being carried out at CHRIST (Deemed to be University), Bangalore currently.

Projects

Project (1)
Project
Be stars provide excellent opportunities to study circumstellar disks. But the disc formation mechanism of classical Be (CBe) stars, known as ‘Be phenomenon’, is an open question in stellar astrophysics. The mystery of Be phenomenon can be understood by studying CBe stars in various locations like clusters and fields. Spectra of Be stars show various interesting emission lines of hydrogen, helium, oxygen, calcium, iron and other elements. Spectroscopic analysis of CaII and FeII emission lines are a less explored area in Be star research. So, we have selected a sample of 118 field CBe stars from the catalogue of Jaschek & Egret (1982) whose medium resolution spectra have been obtained in the wavelength range 3800 – 9000 Å during December, 2007 to January, 2009 with the 2.1-m Himalayan Chandra Telescope, located at Hanle, Ladakh. We are studying the CaII and FeII emission lines for these 118 stars to frame a consolidated picture about Be phenomenon in CBe stars.