Introduction to Young Star

The color–magnitude diagrams of young star clusters show that, particularly at ultraviolet wavelengths, their upper main sequences (MSs) bifurcate into a sequence comprising the bulk population and a blue periphery.

The Hubble Space Telescope (HST) Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program is a HST Director's Discretionary program that is in the process of obtaining a large library of ultraviolet spectroscopic observations of young stars of both high and low masses.

We identify a new mechanism that contributes to the observed disc thickness: rapid changes in the orientation of the galactic plane mix the configuration of young stars.

In contrast to the local normal galaxies where old stars dominate the stellar emission, the young stars in (U)LIRGs contribute with 64% of their luminosity to the total stellar luminosity.

We present Very Large Telescope/NACO high-contrast images in the J, H, K S , and bands of the young star [BHB2007]-1 probing the inclined disk in scattered light and revealing the probable presence of a companion.

In several celebrated examples, incumbents with significant resources have been beaten, in their own core businesses, by young start-ups.

In this paper, we present model spectra based on spectral parameters derived from the observations of young stars in the Orion nebula cluster from the Chandra Orion Ultradeep Project (COUP).

Two bubbles with spatial extents of many kiloparsecs are identified in the disk, and many of the young stars in the southern disk of NGC 247 are located in the walls of these structures.

1841T} and we conclude that NGC 4861 X2 resides in a young star group with 400$\pm$80 M$\odot$.

Many local spiral galaxies have a classic rotating disk of young stars as well as a “bulge” of older red stars at their centers; these two features are considered to be signatures of galaxies that have evolved from their original primordial forms.

This cocktail of phenomena triggered by fast rotation, strong magnetic fields and complex internal dynamics, especially present in very young stars, compromises our ability to detect exoplanets.

Our analysis indeed shows tentative evidence for a diffuse non-thermal X-ray component, indicating that cosmic-ray acceleration needs to be considered in such a young starburst region.

The high resolution UVIT/F154W image reveals far-UV emission within the bar region ( $$\sim 4\,\hbox {kpc}$$ ∼ 4 kpc )—suggesting the presence of hot, young stars in the bar.

The spatial decorrelation of dense molecular gas and young stars observed on ≲1 kpc scales in nearby galaxies indicates rapid dispersal of star-forming regions by stellar feedback.

For a fixed PAH abundance parameter q PAH (the fraction of the total dust mass in PAHs with <103 C atoms), the fraction of the infrared power appearing in the PAH emission features can vary by a factor of two as the starlight spectrum varies from FUV-poor (M31 bulge) to FUV-rich (young starburst).

Upcoming instruments with high angular resolution MIR imaging capabilities such as the JWST could surely make more substantial use of this de-reddening method and help establish a far more complete census of hot, young stars in the GC area than what is possible at the.

Direct imaging is a method of choice for probing the close environment of young stars.

Focusing on the low-mass population and placing the optical counterparts identified in this way in a color-magnitude diagram, we can isolate the young stars out of the detected X-ray sources and obtain age estimates of the various Sco-Cen populations.

Here, we investigate the possibility that IMBHs form in young star clusters via runaway collisions and BH mergers.

Gaia DR2 and APOGEE-2 surveys in combination provide three-dimensional (3D) positions and 3D velocities of young stars in the Orion Molecular Cloud Complex.

The evolution of young stars and disks is driven by the interplay of several processes, notably the accretion and ejection of material.

Also, small size molecule of C12H 8 showed good coincidence with the spectrum observed for young star s.

We obtain that σ Ori E is a very young star (age less than 1 Myr) with an initial mass around 9 M , a surface equatorial magnetic field around 7 kG and having a metallicity Z (mass fraction of heavy elements) around 0.

We have searched for complex organic molecules (COMs) in the young starless core L1521E, and report the first clear detection of dimethyl ether (CH3OCH3), methyl formate (HCOOCH3), and vinyl cyanide (CH2CHCN).

This suggests that a large fraction of very young stars in low-metallicity environments have disks, but the disks are lost on a very short timescale.

In 2007, the young star 1SWASP J140747.

We studied the 3D structure of the star-forming complex and the distribution of tangential velocities of the young stars.

position ramp, and therefore reproduces in a qualitative way the “Hubble law clumps” in planetary nebulae and outflows from young stars.

These stars are located in the association Cepheus OB3, in the field of the young star V733 Cephei.

An analysis of the distribution of proper motions reveals a 20-30 Myr association of young stars, about 300-400 pc away from the far side of the Mon OB1 complex, along the same general line-of-sight.

In order to understand the evolution of planets, it is thus important to study the flare-activity of young stars.

The morphology and dynamics of the system are consistent with an early stage of the collision, where the foreground galaxy (Mrk 739W) is a young star-forming galaxy in an ongoing first passage with its background companion (Mrk 739E).

Recent studies indicate that the progenitors of merging black hole (BH) binaries from young star clusters can undergo a common envelope phase just like isolated binaries.

03}\,$Gpc−3 yr−1 for GW190521-like binaries formed via binary-single interactions in young star clusters.

We estimate "astro-kinematic" distances by combining parallaxes and proper motions with a model for the expected velocity and density distribution of young stars; we show that this adds useful constraints on the stars' distances, and hence luminosities.

We report on the discovery of a sub-Neptune-sized planet orbiting the young star HD 110082 (TOI-1098).

Young star clusters are dynamically active stellar systems and are a common birthplace for massive stars.

The analysis of the MUSE dataset, which provides a map of the ionised gas and a census of Wolf Rayet stars, is complemented with a sample of young star clusters (YSCs) and O star candidates observed with the Hubble Space Telescope (HST) and of giant molecular clouds traced in CO(2-1) emission with the Atacama Large Millimeter/submillimeter Array (ALMA).

This is necessary to study the time evolution of the YSO distribution with respect to the gas and dust compounds that are responsible for the birth of the young stars.

The data support a scenario in which the most compact galaxies have more young star-forming regions per unit area that exhibit less efficient gas heating.

These events are produced by young stars of all masses over evolutionary stages ranging from protostars to diskless stars, with the occurrence rate positively correlated with stellar mass.

Given distinct uncertainties in detailed binary evolution calculations, we investigate a rigorous and model independent upper limit for the production of Be stars through binary interaction and aim to confront this limit with observations of Be stars in young star clusters.

We aim to characterize the physical and chemical properties of fragmented cores during the earliest evolutionary stages in the very young star-forming regions ISOSS J22478+6357 and ISOSS J23053+5953.

The young startups have the opportunity to learn from the practices of the matured startups, to adopt the learning in their working context.

Further observations of larger samples in young star-forming regions are needed to determine if this is a general result.

A pioneering study showed that the fine structure in the luminosity function (LF) of young star clusters contains information about the evolutionary stage (age) and composition of the stellar population.

In Jamele Watkins’s chapter, by performing oppression and empowerment the Young Stars draw on diasporic connections to reclaim their body from the grips of white voyeurism.

We measure the projected half-light radii of young star clusters in 31 galaxies from the Legacy Extragalactic UV Survey (LEGUS).

However, transmission spectroscopy measurements to determine atmospheric composition and mass loss are challenging due to the activity and prominent stellar disk inhomogeneities present on young stars.

To identify nearby young stellar populations that trace this progression, we have designed a comprehensive framework for the identification of young stars and use it to identify ∼3 × 104 candidate young stars within a distance of 333 pc using Gaia DR2.

However, transmission spectroscopy measurements to determine atmospheric composition and mass loss are challenging due to the activity and prominent stellar disk inhomogeneities present on young stars.

The use of Z-pinch facilities makes it possible to carry out well-controlled and diagnosable laboratory experiments to study laboratory jets with scaling parameters close to those of the jets from young stars.

It is shown that the results obtained are consistent with the MHD theory of jets ejected from young stars.

We spatially resolve and constrain the sizes of the dust and ionised gas emission of the innermost regions towards a sample of MYSOs for the first time, and provide high-mass binary statistics of young stars at 2-300 au scales.

Indeed, for different reasons, precise measurements of LiBeB and CNO are difficult, even in our Sun; however, the advent of state-of-the-art ground- and space-based instrumentation has allowed the determination of high-quality abundances in stars of different type, belonging to different Galactic populations, from metal-poor halo stars to young stars in the solar vicinity and from massive stars to cool dwarfs and giants.

If the young starburst of Jil2 had been accompanied by sustained black hole growth, Jil2 may have contributed He iiionising flux to create the large He ii Lyα proximity zone around LBQS 0302−0019.

We explore hierarchical black hole (BH) mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs), accounting for both original and dynamically assembled binary BHs (BBHs).

We report the discovery of J0121+0025, an extremely luminous and young star-forming galaxy (MUV = −24.

Space observatories have provided unprecedented depictions of the many variability behaviors typical of low-mass, young stars.

The long-lived star spot we find on Hubble 4 has significant implications for dynamo models in young stars, as it adds evidence for long lifetimes of magnetic field topologies.

Space observatories have provided unprecedented depictions of the many variability behaviors typical of low-mass, young stars.

Using Zeeman-Doppler Imaging (ZDI), we obtained the first maps of photospheric brightness and large-scale magnetic field at the surface of this young star derived from NIR spectropolarimetric data.

An analysis of the spatial separation between young star clusters and nearby H ii regions has made it possible to determine the position of the corotation radius in the galaxies studied.

Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs).

1, 2021, E-ISSN: 2222-6990 © 2021 HRMARS 98 a renowned singer at that time, failed to appear at the scheduled broadcast for Radio Malaya, young Salmah was asked to fill in, and a young star was born.

The young star is a member of the Cep OB3 association, at a distance of 798 ± 9 pc, and has a ‘cavity’ associated with it.

Protoplanetary discs are made of gas and dust orbiting a young star.

Radiation and fast wind particles ionize the uppermost layers of planetary atmospheres, especially for planets orbiting active, young stars.

Apart from the two well known clusters, IC 348 and NGC 1333, we present five new clustered groups of young stars, which contain between 30 and 300 members, named Autochthe, Alcaeus, Heleus, Electryon and Mestor.

However, theoretical predictions surface light element abundance are challenging because they are also influenced by the uncertainties in the input physics adopted in the calculations as well as the efficiency of several standard and non-standard physical processes active in young stars (i.

Studying rotational variability of young stars is enabling us to investigate a multitude of properties of young star-disc systems.

We argue that all these empirical findings are natural consequences of a picture in which galactic discs are built mainly by smooth and gradual inflow, regulated by feedback from young stars, while galactic spheroids are built by a cooperation between merging, black-hole fuelling, and feedback from AGNs.

7 and are therefore absent in very young star clusters.

To this aim, we have analyzed X-ray properties of young stars in the Orion Nebula Cluster determined with Chandra during the COUP observation as well as accretion data obtained from the photometric catalog of the HST Treasury Program.

This is at odds with measurements in young star forming regions such as Lupus, which find much smaller values, implying that dust radial drift is too efficient in these models.

The young star PDS110 in the Ori OB1a association underwent two similar eclipses in 2008 and 2011, each of which lasted for a period of at least 25 days.

We aim to identify new low-mass companions to young stars using the astrometric measurements provided by the Gaia space mission.

We confirm the difficulties in determining parameters for young stars (age < 200 Myr), due to a combination of intrinsic factors (activity, fast rotation, magnetic fields, etc) which atmospheric models can not easily reproduce and which affect the parameters uncertainty.

We use the angular two-point correlation function (TPCF) to investigate the hierarchical distribution of young star clusters in 12 local (3–18 Mpc) star-forming galaxies using star cluster catalogs obtained with the Hubble Space Telescope (HST) as part of the Treasury Program Legacy ExtraGalactic UV Survey.

Observations of young stars hosting transition disks show that several of them have high accretion rates, despite their disks presenting extended cavities in their dust component.

NGC 6822 contains a disc of H i gas and young stars, oriented at ∼60○ to an extended spheroid composed of old stellar populations.

These kick velocities suggest that globular clusters and nuclear star clusters may retain up to and of their remnant black holes, respectively, while young star clusters would only retain a few tenths of a percent.

Motivated by the recent LIGO/Virgo event GW190521, we investigate whether black holes with masses within or in excess of this “upper-mass gap” can be formed dynamically in young star clusters through strong interactions of massive stars in binaries.

The young star formation observed here in the 17 kpc long turbulent wake of IC3418, due to ram pressure stripping of cold gas surrounded by hot intra-cluster medium, is a unique laboratory that is unavailable in the Milky Way.