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We present a detailed near-infrared study of an embedded cluster located in the hub of the giant molecular cloud G148.24+00.41 of mass $\sim$10$^5$ $M_\odot$, with the TANSPEC instrument mounted on the 3.6 m Devasthal Optical Telescope. The hub is located near the geometric center of the cloud and represents its most massive clump. We studied the central 2 pc $\times$ 2 pc area of the hub with 5$\sigma$ limiting magnitudes of 20.5, 20.1, and 18.6 mag in the $J$, $H$, and $K_s$ bands, respectively. Using the $K_s$-band luminosity function and comparing it with the synthetic clusters, we obtained the age of the cluster as $\sim$0.5 Myr, which was found to corroborate well with the visual extinction versus the age of nearby embedded clusters. We find that the present mass of the cluster is around $\sim$180 $M_\odot$, and the cluster is currently forming stars at a rate of $\sim$330 $M_\odot$ $\rm{Myr}^{-1}$, with an efficiency of $\sim$20%. The cluster is connected to an extended gas reservoir through a filamentary network; thus, we hypothesize that the cluster has the potential to become a richer cluster in a few Myr of time., Comment: 17 pages and 13 figures

We have investigated the physical properties of Planck Galactic Cold Clumps (PGCCs) located in the Galactic Plane, using the JCMT Plane Survey (JPS) and the SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE) survey. By utilising a suite of molecular-line surveys, velocities and distances were assigned to the compact sources within the PGCCs, placing them in a Galactic context. The properties of these compact sources show no large-scale variations with Galactic environment. Investigating the star-forming content of the sample, we find that the luminosity-to-mass ratio (L/M) is an order of magnitude lower than in other Galactic studies, indicating that these objects are hosting lower levels of star formation. Finally, by comparing ATLASGAL sources that are associated or are not associated with PGCCs, we find that those associated with PGCCs are typically colder, denser, and have a lower L/M ratio, hinting that PGCCs are a distinct population of Galactic Plane sources., Comment: 18 pages, 14 figures, 7 tables. Accepted for publication in MNRAS

We conducted a photometric and kinematic analysis of the young open cluster NGC 2345 using CCD \emph{UBV} data from 2-m Himalayan Chandra Telescope (HCT), \emph{Gaia} Data Release 3 (DR3), 2MASS, and the APASS datasets. We found 1732 most probable cluster members with membership probability higher than 70$\%$. The fundamental and structural parameters of the cluster are determined based on the cluster members. The mean proper motion of the cluster is estimated to be $\mu_{\alpha}cos\delta$ = ${-1.34}\pm0.20$ and $\mu_{\delta}$= $1.35\pm 0.21$ mas $yr^{-1}$. Based on the radial density profile, the estimated radius is $\sim$ 12.8 arcmin (10.37 pc). Using color-color and color-magnitude diagrams, we estimate the reddening, age, and distance to be $0.63\pm0.04$ mag, 63 $\pm$ 8 Myr, and 2.78 $\pm$ 0.78 kpc, respectively. The mass function slope for main-sequence stars is determined as $1.2\pm 0.1$. The mass function slope in the core, halo, and overall region indicates a possible hint of mass segregation. The cluster's dynamical relaxation time is 177.6 Myr, meaning ongoing mass segregation, with complete equilibrium expected in 100-110 Myr. Apex coordinates are determined as $-40^{\circ}.89 \pm 0.12, -44^{\circ}.99 \pm 0.15$. The cluster's orbit in the Galaxy suggests early dissociation in field stars due to its close proximity to the Galactic disk., Comment: Accepted for publication in A&A and 21 pages, 22 Figures

The relative importance of magnetic fields, turbulence, and gravity in the early phases of star formation is still not well understood. We report the first high-resolution dust polarization observations at 850 $\mu$m around the most massive clump, located at the hub of the Giant Molecular Cloud G148.24+00.41, using SCUBA-2/POL-2 at the James Clerk Maxwell Telescope. We find that the degree of polarization decreases steadily towards the denser portion of the cloud. Comparing the intensity gradients and local gravity with the magnetic field orientations, we find that local gravity plays a dominant role in driving the gas collapse as the magnetic field orientations and gravity vectors seem to point towards the dense clumps. We also find evidence of U-shaped magnetic field morphology towards a small-scale elongated structure associated with the central clump, hinting at converging accretion flows towards the clump. Our observation has resolved the massive clump into multiple substructures. We study the magnetic field properties of two regions, central clump (CC) and northeastern elongated structure (NES). Using the modified Davis-Chandrasekhar Fermi method, we determine that the magnetic field strengths of CC and NES are $\sim$24.0 $\pm$ 6.0 $\mu$G and 20.0 $\pm$ 5.0 $\mu$G, respectively. The mass-to-flux ratios are found to be magnetically transcritical/supercritical, while the Alfv$\acute{\text{e}}$n Mach number indicates a trans-Alfv$\acute{\text{e}}$nic state in both regions. These results, along with Virial analysis, suggest that at the hub of G148.24+00.41, gravitational energy has an edge over magnetic and kinetic energies., Comment: 17 pages, 23 figures

We present the study of four FUV stars in the field of open cluster NGC 2420 using the Ultra Violet Imaging Telescope (UVIT) mounted on AstroSat. The three stars 525, 527, and 560 are members, while star 646 is a non-member of the cluster. To characterize and determine the parameters of these stars, multi-wavelength spectral energy distributions (SEDs) are analyzed using UV, optical, and IR data sets. For all four FUV bright stars, a two-component SED model fits well. Our findings indicate that two stars, 525 and 560, are binary BSS systems. These binary BSS systems may have formed in a tertiary system due to mass transfer from an evolved outer tertiary companion. Star 527 is a binary system of a BSS and an extremely low-mass (ELM) white dwarf, while Star 646 is a binary system of a horizontal branch star and an ELM white dwarf. The effective temperatures, radii, luminosities and masses of the two ELMs are (10250, 11500) K, (0.42, 0.12) Rsun, (1.61, 0.23) Lsun, and (0.186, 0.170) Msun, respectively. The star 527 could be a post-mass transfer system and may have originated through the Case A/B mass transfer process in a low-density environment. The cooling age of the ELMs is < 1 Myr, indicating that they have only recently formed., Comment: Accepted in ApJ, 9 pages, 4 figures, 1 table

Cygnus-X is considered a region of interest for high-energy astrophysics, since the Cygnus OB2 association has been confirmed as a PeVatron in the Cygnus cocoon. In this research note, we present new high-resolution (16'') $^{12,13}$CO(J=1$\rightarrow$0) and C$^{18}$O (J=1$\rightarrow$0) observations obtained with the Nobeyama 45-m radiotelescope, to complement the Nobeyama Cygnus-X Survey. We discovered 19 new C$^{18}$O clumps associated with the star-forming regions DR-6W, DR-9, and DR13S. We present the physical parameters of these clumps, which are consistent with the neighboring covered regions. We confirm the clumpy nature of these regions and of a filament located between DR6 and DR6W. These results strongly suggest that star formation occurs in these regions with clumps of sizes $\sim$10$^{-1}$ pc, masses $\sim$10$^2$ M$_\odot$, and H$_2$ densities of $\sim$10$^4$ cm$^{-3}$., Comment: 8 pages, 3 Figures, 1 Table. https://pos.sissa.it/444/631/pdf

In the present study, we identified an extremely low-mass white dwarf as a companion to a low luminous blue straggler star within the Galactic globular cluster NGC 362. To conduct the analysis, we utilized data obtained from various sources, including AstroSat Ultra Violet Imaging Telescope, UVOT, and the 2.2-m ESO telescope. By examining the spectral energy distribution of the blue straggler star candidate, we successfully identified an extremely low mass white dwarf as its binary companion. We determined the effective temperature, radius, and luminosity for both, the extremely low-mass white dwarf and the blue straggler star candidate. Specifically, the extremely low-mass white dwarf exhibits an effective temperature of 15000 K, a radius of 0.17 Rsun, a luminosity of 1.40 Lsun, and a mass range of 0.19-0.20 Msun. Furthermore, the position of the straggler star within the cluster suggests their formation via the Case A/B mass-transfer mechanism in a low-density environment., Comment: 6 pages, 2 figures, Submitted: 31 May, 2023 and Accepted: 26 July 2023

The 4K$\times$4K CCD Imager is the first light instrument for the 3.6m Devasthal Optical Telescope and is producing broad-band imaging observations of many Galactic and extra-galactic sources since 2015-2016. Capabilities of the CCD Imager are demonstrated recently through several publications using the well-calibrated multi-band deep photometric results as expected from other similar facilities globally. In this article, we summarize some of the recent up-gradations made to improve the Imager, i.e., mounting the new filter wheel casing, replacing stray light baffles and discussing the fringe pattern corrections in redder filters. Some of the new science initiatives like galaxy-embedded faint point sources including WR stars and the observations of low surface brightness galaxy clusters are also discussed., Comment: Accepted for publication in the Journal of Astronomical Instrumentation, 20 pages, 17 figures and 2 tables

We present here the results of eight years of our near-simultaneous optical/near-infrared spectro-photometric monitoring of bonafide FUor candidate `V2493 Cyg' starting from 2013 September to 2021 June. During our optical monitoring period (between October 16, 2015 and December 30, 2019), the V2493 Cyg is slowly dimming with an average dimming rate of $\sim$26.6 $\pm$ 5.6 mmag/yr in V band. Our optical photometric colors show a significant reddening of the source post the second outburst pointing towards a gradual expansion of the emitting region post the second outburst. The mid infra-red colors, on the contrary, exhibits a blueing trend which can be attributed to the brightening of the disc due to the outburst. Our spectroscopic monitoring shows a dramatic variation of the H$\alpha$ line as it transitioned from absorption feature to the emission feature and back. Such transition can possibly be explained by the variation in the wind structure in combination with accretion. Combining our time evolution spectra of the Ca II infra-red triplet lines with the previously published spectra of V2493 Cyg, we find that the accretion region has stabilised compared to the early days of the outburst. The evolution of the O I $\lambda$7773 \AA~ line also points towards the stabilization of the circumstellar disc post the second outburst., Comment: 34 pages, 12 figures, 6 tables, accepted for publication in ApJ

Observing the spatial distribution and excitation processes of atomic and molecular gas in the inner regions (< 20 au) of young (< 10 Myr) protoplanetary disks helps us to understand the conditions for the formation and evolution of planetary systems. In the framework of the PENELLOPE and ULLYSES projects, we aim to characterize the atomic and molecular component of protoplanetary disks in a sample of 11 Classical T Tauri Stars (CTTs) of the Orion OB1 and $\sigma$-Orionis associations. We analyzed the flux-calibrated optical-forbidden lines and the fluorescent ultraviolet $\rm H_2$ progressions using spectra acquired with ESPRESSO at VLT, UVES at VLT and HST-COS. Line morphologies were characterized through Gaussian decomposition. We then focused on the properties of the narrow low-velocity (FWHM < 40 $km$ $s^{-1}$ and |$v_p$| < 30 $km$ $s^{-1}$) component (NLVC) of the [OI] 630 nm line, compared with the properties of the UV-$\rm H_2$ lines. We found that the [OI]630 NLVC and the UV-$\rm H_2$ lines are strongly correlated in terms of peak velocities, full width at half maximum, and luminosity. The luminosities of the [OI]630 NLVC and UV-$\rm H_2$ correlate with the accretion luminosity with a similar slope, as well as with the luminosity of the CIV 154.8, 155 nm doublet. We discuss such correlations in the framework of the currently suggested excitation processes for the [OI]630 NLVC. Our results can be interpreted in a scenario in which the [OI]630 NLVC and UV-$\rm H_2$ have a common disk origin with a partially overlapped radial extension. We also suggest that the excitation of the [OI] NLVC is mainly induced by stellar FUV continuum photons more than being of thermal origin. This study demonstrates the potential of contemporaneous wide-band high-resolution spectroscopy in linking different tracers of protoplanetary disks., Comment: 24 pages, 15 figures, 6 tables. Accepted for publication in Astronomy & Astrophysics

We present the intra-cluster kinematics and dynamics of three open clusters: NGC 1193, NGC 2355, and King 12 by incorporating kinematical and photometric data from Gaia DR3, as well as a ground-based telescope. After selecting cluster members based on proper motion data, clusters' fundamental and structural parameters are investigated. We found the clusters at distances of 4.45, 1.97, and 3.34 kpc from the Sun in the direction of the Galactic anticenter. The luminosity function of the cluster NGC 1193 is flat, whereas it advances towards the fainter ends of the other two clusters. We observed a dip in the luminosity function of King 12. The mass function slopes for all three clusters differ from the solar neighbourhood reported by Salpeter, with NGC 1193 and NGC 2355 being flatter and King 12 having a higher value than the Salpeter value. The intra-cluster kinematics depict that stars in King 12 are moving outwards due to tidal forces from the Galactic disc, which we confirmed by plotting the cluster's orbit in the Galaxy. Stars in NGC 2355 are moving with smaller relative velocities and have zero mean relative motion, which signifies that the cluster is neither contracting nor evaporating. The Galactic orbits of NGC 1193 suggest that it is orbiting farther from the Galactic disc, and so is less impacted by the Galactic tidal forces., Comment: This article has been accepted for the publication in the Monthly Notices of the Royal Astronomical Society and contains total 19 pages, 22 figures and 11 tables

We report the discovery of four blue lurkers with low and extremely low-mass white dwarf (ELM WDs) companions in the Galactic globular cluster NGC 362 using AstroSat Ultra Violet Imaging Telescope (UVIT). We analyzed the multi-wavelength spectral energy distribution (SED) of FUV-bright MS stars using data from the UVIT, UVOT, GAIA EDR3, and 2.2m ESO/MPI telescopes. Two each of low-mass WDs and ELM WDs are found as companions for the four blue lurkers by the fitting of two-component SED models. The effective temperatures, radii, luminosities, and masses of two low-mass WDs are (35000, 23000) K, (0.04, 0.05) Rsun , (1.45, 0.22) Lsun , and (0.2, 0.2) Msun, while the two ELM WDs are (14750, 14750) K, (0.09, 0.10) Rsun, (0.34, 0.40) Lsun, and (0.18, 0.18) Msun. The position of blue lurkers within the cluster shows that they originated via the Case A/B mass-transfer mechanism in a low-density environment. This is the first detection of blue lurkers with low-mass WDs and ELM WDs as companions in a globular cluster. The companion cooling age is less than 4 Myr, which suggests that they were just recently formed. These binary systems might have originated due to the cluster recent core collapse., Comment: 6 pages, 3 figures, 1 table

We report the discovery of extremely low-mass white dwarfs (ELM WDs) as a companion of blue straggler stars (BSSs) in the Galactic globular cluster NGC 362 using images from AstroSats Ultra Violet Imaging Telescope (UVIT). Spectral Energy Distributions (SEDs) for 26 FUV bright member BSSs are created using data from the UVIT, UVOT, Gaia EDR3, and the 2.2 m ESO/MPI telescope. A single SED is fitted to 14 BSSs, whereas double-SED fits revealed ELM WDs as binary companions in 12 of the 26 BSSs studied. The effective temperature, radius, luminosity and mass of the 12 ELM WDs are found to have a range (Teff = 9750-18000 K, R = 0.1-0.4 Rsun, L = 0.4-3.3 Lsun, and M =0.16-0.20 Msun). These suggest that 12 BSSs are post-mass-transfer systems formed through Case A/B mass transfer pathway. To the best of our knowledge, this is the first finding of ELM WDs as companions to BSS in globular clusters. This cluster is known to have a binary BSS sequence and the 12 binary and 14 single BSSs (as classified by the SEDs) follow the mass transfer and collisional sequence of BSS in the colour-magnitude diagram. The cooling ages of 9 of the ELM WDs are found to be younger than 500 Myr. Though the binary BSSs may have formed during the core-collapse (approx 200 Myr) or as part of the dynamical evolution of the cluster, they provide new insights on the dynamics of this cluster., Comment: 16 pages, 10 figures, accepted for publication in ApJ

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 was determined to be ($\mu_{\alpha} cos{\delta}$, $\mu_{\delta}$)= ($-1.076\pm0.008$, $0.152\pm0.007$)~mas~yr$^{-1}$. The blue straggler stars (BSS) of the cluster were found to be located in the central region. Theoretical isochrones of metallicity Z$_{metal}$= 0.008 were compared to the color-magnitude diagram (CMD) of Be 27. As a result, a heliocentric distance of 4.8$\pm$0.2 kpc and log (age) = 9.36$\pm$0.03 were determined for Be 27. The Galactic orbits are derived using the Galactic potential model which demonstrate that Be 27 follows a circular path around the Galactic center. The cluster does not seem to be affected much by the tidal forces from the Galactic thin disk., Comment: 22 pages, 12 figures and 2 tables. Accepted by New Astronomy

This paper presents a deep investigation of two open clusters, Haffner 22 and Melotte 71, using astrometric and photometric data from Gaia EDR3. We identified 382 and 597 most probable cluster members with membership probability higher than 50 percent. Mean proper motion in RA and DEC are estimated as -1.63 and 2.889 respectively for Haffner 22 and -2.398 and 4.210 for Melotte 71. A comparison of observed CMDs with theoretical isochrones leads to an age of 2.25 and 1.27 Gyr for these clusters. The distances 2.88 and 2.28 kpc based on parallax are comparable with the values derived by isochrone fitting method. Five and four blue straggler stars are identified as cluster members in Haffner 22 and Melotte 71 respectively. Based on the relative number of high velocity (binary) and single stars, we inferred binary fractions for both clusters. We found binary content is larger in core region. Mass function slope is in good agreement with the Salpeter's value while it is flat for Haffner 22. Evidence for the existence of mass segregation effect is observed in both clusters. Using the Galactic potential models, Galactic orbits are derived, indicating that both clusters follow a circular path around the Galactic center, evolving slowly., Comment: This article contains 15 figures and 9 tables. This paper has been accepted for the publication in Publications of the Astronomical Society of the Pacific. arXiv admin note: text overlap with arXiv:2103.04596

The $UBVRI$ CCD photometric data of open star cluster NGC 1513 are obtained with the 3.6-m Indo-Belgian Devasthal optical telescope (DOT). Analyses of the GAIA EDR3 astrometric data have identified 106 possible cluster members. The mean proper motion of the cluster is estimated as $\mu_{\alpha}Cos{\delta}=1.29\pm0.02$ and $\mu_{\delta}=-3.74\pm0.02$ mas yr$^{-1}$. Estimated values of reddening $E(B-V)$ and distance to the NGC 1513 are 0.65$\pm$0.03 mag and 1.33$\pm$0.1 kpc respectively. An age of $225\pm25$ Myr is assigned to the cluster by comparing theoretical isochrones with deep observed cluster sequence. Using observations taken with the 3.6-m DOT, values of distance and age of the galactic globular cluster NGC 4147 are estimated as $18.2\pm0.2$ Kpc and $14\pm2$ Gyr respectively. The optical observations of planetary transit around white dwarf WD1145+017 and $K$-band imaging of star-forming region Sharpless Sh 2-61 demonstrate observing capability of 3.6-m DOT. Optical and near-infrared observations of celestial objects and events are being carried out routinely with the 3.6-m DOT. They indicate that the performance of the telescope is at par with those of other similar telescopes located elsewhere in the world. We therefore state that this observing facility augurs well for multi-wavelength astronomy including study of astrophysical jets., Comment: Accepted for Special Issue of Journal of Astrophysics and Astronomy, 2022, Astrophysical jets and observational facilities: National perspective, 05-09 April 2021, ARIES Nainital

The Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Director's Discretionary Program of low-mass pre-main-sequence stars, coupled with forthcoming data from ALMA and JWST, will provide the foundation to revolutionize our understanding of the relationship between young stars and their protoplanetary disks. A comprehensive evaluation of the physics of disk evolution and planet formation requires understanding the intricate relationships between mass accretion, mass outflow, and disk structure. Here we describe the Outflows and Disks around Young Stars: Synergies for the Exploration of ULLYSES Spectra (ODYSSEUS) Survey and present initial results of the classical T Tauri Star CVSO 109 in Orion OB1b as a demonstration of the science that will result from the survey. ODYSSEUS will analyze the ULLYSES spectral database, ensuring a uniform and systematic approach in order to (1) measure how the accretion flow depends on the accretion rate and magnetic structures, (2) determine where winds and jets are launched and how mass-loss rates compare with accretion, and (3) establish the influence of FUV radiation on the chemistry of the warm inner regions of planet-forming disks. ODYSSEUS will also acquire and provide contemporaneous observations at X-ray, optical, NIR, and millimeter wavelengths to enhance the impact of the ULLYSES data. Our goal is to provide a consistent framework to accurately measure the level and evolution of mass accretion in protoplanetary disks, the properties and magnitudes of inner-disk mass loss, and the influence of UV radiation fields that determine ionization levels and drive disk chemistry., Comment: accepted to ApJ

The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae when its light curve showed a $\sim$4.25 magnitude outburst. We present multi-wavelength photometric and spectroscopic follow-up observations of this source since 2020 August and identify it as the newest member of the FUor/EXor family of sources. We find that the present brightening of Gaia 20eae is not due to the dust clearing event but due to an intrinsic change in the spectral energy distribution. The light curve of Gaia 20eae shows a transition stage during which most of its brightness ($\sim$3.4 mag) has occurred at a short timescale of 34 days with a rise-rate of 3 mag/month. Gaia 20eae has now started to decay at a rate of 0.3 mag/month. We have detected a strong P Cygni profile in H$\alpha$ which indicates the presence of winds originating from regions close to the accretion. We find signatures of very strong and turbulent outflow and accretion in Gaia 20eae during this outburst phase. We have also detected a red-shifted absorption component in all the Ca II IR triplet lines consistent with signature of hot in-falling gas in the magnetospheric accretion funnel. This enables us to constrain the viewing angle with respect to the accretion funnel. Our investigation of Gaia 20eae points towards magnetospheric accretion being the phenomenon for the current outburst., Comment: 17 pages, 11 figures, Accepted in Astrophysical Journal

In the present work, recent characterization results of the 4K$\times$4K CCD Imager (a first light instrument of the 3.6m Devasthal Optical Telescope; DOT) and photometric calibrations are discussed, along with measurements of the extinction coefficients and sky brightness values at the location of the 3.6m DOT site based on the imaging data taken between 2016 and 2021. For the 4K$\times$4K CCD Imager, all given combinations of gains (1, 2, 3, 5, and 10 e$^-$/ADU) and readout noise values for the three readout speeds (100 kHz, 500 kHz, and 1 MHz) are verified using the sky flats and bias frames taken during early 2021; measured values resemble well with the theoretical ones. Using color-color and color-magnitude transformation equations, color coefficients ($\alpha$) and zero-points ($\beta$) are determined to constrain and examine their long-term consistencies and any possible evolution based on $UBVRI$ observations of several Landolt standard fields observed during 2016-2021. Our present analysis exhibits consistency among estimated $\alpha$ values within the 1$\sigma$ and does not show any noticeable trend with time. We also found that the photometric errors and limiting magnitudes computed using the CCD Imager data follow the simulated ones published earlier. The average extinction coefficients, their seasonal variations, and zenith night-sky brightness values for the moon-less nights for all ten Bessell and SDSS filters are also estimated and found comparable to those reported for other good astronomical sites., Comment: Published in Special Issue of Journal of Astrophysics and Astronomy, 2022; updated to match the accepted version

We present a comprehensive multiwavelength investigation of a likely massive young cluster `IRAS 05100+3723' and its environment with the aim to understand its formation history and feedback effects. We find that IRAS 05100+3723 is a distant ($\sim$3.2 kpc), moderate mass ($\sim$500 \msun), young ($\sim$3 Myr) cluster with its most massive star being an O8.5V-type. From spectral modeling, we estimate the effective temperature and log $g$ of the star as $\sim$33,000 K and $\sim$3.8, respectively. Our radio continuum observations reveal that the star has ionized its environment forming an HII region of size $\sim$2.7 pc, temperature $\sim$5,700 K, and electron density $\sim$165 cm$^{-3}$. However, our large-scale dust maps reveal that it has heated the dust up to several parsecs ($\sim$10 pc) in the range 17$-$28 K and the morphology of warm dust emission resembles a bipolar HII region. From dust and $^{13}$CO gas analyses, we find evidences that the formation of the HII region has occurred at the very end of a long filamentary cloud around 3 Myr ago, likely due to edge collapse of the filament. We show that the HII region is currently compressing a clump of mass $\sim$2700 \msun at its western outskirts, at the junction of the HII region and filament. We observe several 70 $\mu$m point sources of intermediate-mass and class 0 nature within the clump. We attribute these sources as the second generation stars of the complex. We propose that the star formation in the clump is either induced or being facilitated by the compression of the expanding HII region onto the inflowing filamentary material., Comment: ApJ, accepted

We present the results from our time-series imaging data taken with the 1.3m Devasthal fast optical telescope and 0.81m Tenagara telescope in $V$, $R_{c}$, $I_{c}$ bands covering an area of $\sim18^\prime.4\times 18^\prime.4$ towards the star-forming region Sh 2-190. This photometric data helped us to explore the nature of the variability of pre-main sequence (PMS) stars. We have identified 85 PMS variables, i.e., 37 Class II and 48 Class III sources. Forty-five of the PMS variables are showing periodicity in their light curves. We show that the stars with thicker discs and envelopes rotate slower and exhibit larger photometric variations compared to their disc-less counterparts. This result suggests that rotation of the PMS stars is regulated by the presence of circumstellar discs. We also found that the period of the stars show a decreasing trend with increasing mass in the range of $\sim$0.5-2.5 M$_\odot$. Our result indicates that most of the variability in Class II sources is ascribed to the presence of thick disc, while the presence of cool spots on the stellar surface causes the brightness variation in Class III sources. X-ray activities in the PMS stars were found to be at the saturation level reported for the main sequence (MS) stars. The younger counterparts of the PMS variables are showing less X-ray activity hinting towards a less significant role of a stellar disc in X-ray generation., Comment: Accepted for publication in ApJ

This paper presents an investigation of an old age open cluster King 11 using Gaia's Early Data Release 3 (EDR3) data. Considering the stars with membership probability ($P_{\mu}$) $> 90\%$, we identified 676 most probable cluster members within the cluster's limiting radius. The mean proper motion (PM) for King 11 is determined as: $\mu_{x}=-3.391\pm0.006$ and $\mu_{y}=-0.660\pm0.004$ mas yr$^{-1}$. The blue straggler stars (BSS) of King 11 show a centrally concentrated radial distribution. The values of limiting radius, age, and distance are determined as 18.51 arcmin, 3.63$\pm$0.42 Gyr and $3.33\pm0.15$ kpc, respectively. The cluster's apex coordinates ($A=267.84^{\circ} \pm 1.01^{\circ}$, $D=-27.48^{\circ} \pm 1.03^{\circ}$) are determined using the apex diagram (AD) method and verified using the ($\mu_U$,$\mu_T$) diagram. We also obtained the orbit that the cluster follows in the Galaxy and estimated its tentative birthplace in the disk. The resulting spatial velocity of King 11 is 60.2 $\pm$ 2.16 km s$^{-1}$. A significant oscillation along the $Z$-coordinate up to 0.556$\pm$0.022~kpc is determined.

The membership determination for open clusters in noisy environments of the Milky Way is still an open problem. In this paper, our main aim is provide the membership probability of stars using proper motions and parallax values of stars using Gaia EDR3 astrometry. Apart from the Gaia astrometry, we have also used other photometric data sets like UKIDSS, WISE, APASS and Pan-STARRS1 in order to understand cluster properties from optical to mid-infrared regions. We selected 438 likely members with membership probability higher than $50\%$ and G$\le$20 mag. We obtained the mean value of proper motion as $\mu_{x}=1.27\pm0.001$ and $\mu_{y}=-0.73\pm0.002$ mas yr$^{-1}$. The cluster's radius is determined as 7.5 arcmin (5.67 pc) using radial density profile. Our analysis suggests that NGC 1348 is located at a distance of $2.6\pm0.05$ kpc. The mass function slope is found to be $1.30\pm0.18$ in the mass range 1.0$-$4.1 $M_\odot$, which is in fair agreement with Salpeter's value within the 1$\sigma$ uncertainty. The present study validates that NGC 1348 is a dynamically relaxed cluster. We computed the apex coordinates $(A, D)$ for NGC 1348 as $(A_\circ, D_\circ)$ = $(-23^{\textrm{o}}.815\pm 0^{\textrm{o}}.135$, $-22^{\textrm{o}}.228\pm 0^{\textrm{o}}.105)$. In addition, calculations of the velocity ellipsoid parameters (VEPs), matrix elements $\mu_{ij}$, direction cosines ($l_j$, $m_j$, $n_j$) and the Galactic longitude of the vertex have been also conducted in this analysis., Comment: 14 Figures, 4 Tables, Accepted for publication by the Publication of the Astronomical Society of Japan (PASJ)