Search Publications
A Reinforcement Learning-Based Follow-up Framework
Astudillo, Javiera; Protopapas, Pavlos; Pichara, Karim +1 more
Classification and characterization of variable and transient phenomena are critical for astrophysics and cosmology. Given the volume of nightly data produced by ongoing and future surveys such as LSST, it is critical to develop automatic tools that assist in observation decision-making, maximizing scientific output without resource wastage. We pr…
A Gaia based analysis of open cluster Berkeley 27
Bisht, D.; Yadav, R. K. S.; Rangwal, G. +2 more
In this paper, we have used the Gaia's Data Release-3 (DR3) data to study an intermediate-age open cluster Berkeley 27 (Be 27). A total of 131 most probable cluster members are picked within the cluster's radius based on the membership probability (> 80%). The cluster's radius was estimated as 3.74 arcmin. The mean proper motion (PM) of Be 27 w…
HI line analysis of Herbig Ae/Be stars using X-Shooter spectra
Arun, R.; Mathew, Blesson; Shridharan, B. +1 more
Herbig Ae/Be stars are intermediate-mass pre-main sequence stars undergoing accretion through their circumstellar disk. The optical and infrared (IR) spectra of HAeBe stars show HI emission lines belonging to Balmer, Paschen and Brackett series. We used the archival X-Shooter spectra available for 109 HAeBe stars from Vioque et al. (2018) and anal…
Six Newly Discovered Eclipsing Binary Systems in the TESS field
Ulaş, Burak; Ayan, Vildan
We present the first detailed investigation of six eclipsing binary systems in the TESS field. The TESS light curves of the targets are analyzed by determining the initial effective temperatures via SED fits. The absolute parameters are derived and the systems are compared to well-known binaries of the same type. Results show that CD-58791, CD-621…
The planetary system around HD 190622 (TOI-1054). Measuring the gas content of low-mass planets orbiting F-stars
Alonso, R.; Deleuil, M.; Erikson, A. +107 more
Context. Giant planets are known to dominate the long-term stability of planetary systems due to their prevailing gravitational interactions, but they are also thought to play an important role in planet formation. Observational constraints improve our understanding of planetary formation processes such as the delivery of volatile-rich planetesima…
Statistical study of extreme-ultraviolet nanoflares in the quiet-Sun transition region
Fludra, A.
Aims: We carried out a large statistical study of ubiquitous small-scale extreme-ultraviolet (EUV) brightenings in the nanoflare energy range in the quiet-Sun transition region to derive their properties, estimate their contribution to the heating of the solar atmosphere, and compare their numbers to the coronal events published in the litera…
Far ultra-violet insights into NGC 1399's globular cluster population
Kundu, Arunav; Dage, Kristen C.; Zepf, Stephen E. +2 more
We investigate archival Hubble Space Telescope ACS/SBC F140LP observations of NGC 1399 to search for evidence of multiple stellar populations in extragalactic globular clusters. Enhanced far-ultraviolet (FUV) populations are thought to be indicators of He-enhanced second generation populations in globular clusters, specifically extreme/blue horizo…
Analysis of metallicities of open clusters in the Galactic disc
Li, Zhongmu; Deng, Yangyang
The metallicities of open clusters (OCs) are probes for many Galactic disc properties, such as age-metallicity relation and abundance gradient evolution. In recent years, a large number of newly found OCs or OC candidates have been reported. However, the metallicity values of OCs in the Galactic disc in different works vary from each other. In par…
2021 superoutburst of the WZ Sge-type dwarf nova V627 Pegasi lacks an early superhump phase
Ruiz, Javier; Nogami, Daisaku; Tampo, Yusuke +27 more
Superoutbursts in WZ Sge-type dwarf novae (DNe) are characterized by both early superhumps and ordinary superhumps originating from the 2 : 1 and 3 : 1 resonances, respectively. However, some WZ Sge-type DNe show a superoutburst lacking early superhumps; it is not well established how these differ from superoutbursts with an early superhump phase.…
PAH emission features in star-forming regions and late type stars
Kumar, Brijesh; Rastogi, Shantanu; Anand, Rahul Kumar
Mid-infrared emission spectra, obtained from ISO archive, of thirteen astrophysical objects as well as computed spectra of 27 polycyclic aromatic hydrocarbon (PAH) molecules are studied. All the objects show strong aromatic infrared band (AIB) features with variations that correlate with object type. Based on AIB peak positions, the features for I…