A13CO and C18O Survey of the Molecular Gas Around Young Stellar Clusters within 1 Kiloparsec of the Sun

2003 ◽  
Vol 126 (1) ◽  
pp. 286-310 ◽  
Author(s):  
Naomi A. Ridge ◽  
T. L. Wilson ◽  
S. T. Megeath ◽  
L. E. Allen ◽  
P. C. Myers
Keyword(s):  
Molecular Gas ◽  
The Sun ◽  
Stellar Clusters

scholarly journals A census of the nearby Pisces-Eridanus stellar stream

2020 ◽  
Vol 638 ◽  
pp. A9 ◽  
Author(s):  
Siegfried Röser ◽  
Elena Schilbach
Keyword(s):  
Luminosity Function ◽  
Open Cluster ◽  
Space Velocity ◽  
Mass Function ◽  
Molecular Gas ◽  
Cylindrical Shape ◽  
The Sun ◽  
Data Set ◽  
Mass Segregation ◽  
Formation Efficiency

Aims. Within a sphere of 400 pc radius around the Sun, we aim to search for members of the Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data Release 2 data set. We compare basic astrophysical characteristics of the stream with those of the Pleiades. Methods. We used a modified convergent-point method to identify stars with 2D velocities consistent with the space velocity of the Psc-Eri stream and the Pleiades, respectively. Results. In a G magnitude range from 5.1 mag to 19.3 mag, we found 1387 members of the Psc-Eri stream at distances between 80 and 380 pc from the Sun. The stream has a nearly cylindrical shape with a length of at least 700 pc and a thickness of 100 pc. The accumulated stellar mass of the 1387 members amounts to about 770 M⊙, and the stream is gravitationally unbound. For the stream, we found an age of about 135 Myr. In many astrophysical properties, Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its age, its luminosity function, its present-day mass function, as well as in its total mass. Nonetheless, the two stellar ensembles are completely different in their physical appearance. We cautiously give two possible explanations for this disagreement: (i) the star formation efficiency in their parental molecular clouds was higher for the Pleiades than for Psc-Eri, and/or (ii) the Pleiades had a higher primordial mass segregation immediately after the expulsion of the molecular gas of the parental cloud.

scholarly journals Towards a multi-scale understanding of the gas-star formation cycle in the Central Molecular Zone

2016 ◽  
Vol 11 (S322) ◽  
pp. 64-74
Author(s):  
J. M. Diederik Kruijssen
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
High Redshift ◽  
Three Dimensional ◽  
Orbital Dynamics ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
High Redshift Galaxies ◽  
Multi Scale ◽  
The Galaxy

AbstractThe Central Molecular Zone (CMZ, the central 500 pc of the Milky Way) contains the largest reservoir of high-density molecular gas in the Galaxy, but forms stars at a rate 10–100 times below commonly-used star formation relations. We discuss recent efforts in understanding how the nearest galactic nucleus forms its stars. The latest models of the gas inflow, star formation, and feedback duty cycle reproduce the main observable features of the CMZ, showing that star formation is episodic and that the CMZ currently resides at a star formation minimum. Using orbital modelling, we derive the three-dimensional geometry of the CMZ and show how the orbital dynamics and the star formation potential of the gas are closely coupled. We discuss how this coupling reveals the physics of star formation and feedback under the conditions seen in high-redshift galaxies, and promotes the formation of the densest stellar clusters in the Galaxy.

scholarly journals Extra-Galactic Star Formation Revealed

2004 ◽  
Vol 221 ◽  
pp. 107-117
Author(s):  
Eva Schinnerer
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
High Redshift ◽  
Gas Content ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
High Redshift Galaxies ◽  
Nearby Galaxies ◽  
Massive Clusters

High angular resolution observations of nearby galaxies in the optical using ground-based and space-based telescopes have not only revealed the presence of young stellar clusters, but also allowed to study their properties in various dynamical environments. These studies have shown that young massive clusters (YMCs) have typical masses of a few 1000 M⊙ and sizes of a few parsec irrespective of their site of formation (such as bulges, spiral arms, starburst rings, or mergers). This points toward a universal formation mechanism for these stellar clusters.Observations of the dust and gas content in high redshift galaxies allows one to study the reservoir for star formation in the early universe. These studies reveal extremely high star formation rates of a few 1000 M⊙ yr−1, while the distribution of the molecular gas still seems to be comparable to what is observed in the local universe. The detection of considerable amounts of molecular gas via its CO lines in the highest redshifted QSOs known today (up to z=6.4) indicates that star formation in the early universe has already produced considerable amounts of metals.

scholarly journals Rise and fall of molecular clouds across the M 33 disk

2019 ◽  
Vol 622 ◽  
pp. A171 ◽  
Author(s):  
Edvige Corbelli ◽  
Jonathan Braine ◽  
Carlo Giovanardi
Keyword(s):  
Molecular Clouds ◽  
Line Emission ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
Giant Molecular Clouds ◽  
Hii Region ◽  
Star Forming ◽  
Outer Disk ◽  
Low Mass ◽  
The Mean

We carried out deep searches for CO line emission in the outer disk of M 33, at R >  7 kpc, and examined the dynamical conditions that can explain variations in the mass distribution of the molecular cloud throughout the disk of M 33. We used the IRAM-30 m telescope to search for CO lines in the outer disk toward 12 faint mid-infrared (MIR) selected sources and in an area of the southern outer disk hosting MA1, a bright HII region. We detect narrow CO lines at the location of two MIR sources at galactocentric distances of about 8 kpc that are associated with low-mass young stellar clusters, and at four locations in the proximity of MA1. The paucity of CO lines at the location of weak MIR-selected sources probably arises because most of them are not star-forming sites in M 33, but background sources. Although very uncertain, the total molecular mass of the detected clouds around MA1 is lower than expected given the stellar mass of the cluster, because dispersal of the molecular gas is taking place as the HII region expands. The mean mass of the giant molecular clouds (GMCs) in M 33 decreases radially by a factor 2 from the center out to 4 kpc, then it stays constant until it drops at R >  7 kpc. We suggest that GMCs become more massive toward the center because of the fast rotation of the disk, which drives mass growth by coalescence of smaller condensations as they cross the arms. The analysis of both HI and CO spectral data gives the consistent result that corotation of the two main arms in this galaxy is at a radius of 4.7 ± 0.3 kpc, and spiral shock waves become subsonic beyond 3.9 kpc. Perturbations are quenched beyond 6.5 kpc, where CO lines have been detected only around sporadic condensations associated with UV and MIR emission.

scholarly journals Distances of Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 109-121 ◽  
Author(s):  
Yervant Terzian
Keyword(s):  
Physical Parameter ◽  
Main Sequence ◽  
Planetary Nebulae ◽  
Variable Stars ◽  
Stellar Systems ◽  
The Sun ◽  
Stellar Clusters ◽  
Main Sequence Stars ◽  
The Universe ◽  
Fundamental Physical

One of the most fundamental physical parameter in astronomy is the distance to the objects we detect in the universe. For many classes of astronomical objects, accurate and proven methods have been developed to determine their distances. Such classes of objects include stars within ∼100 pc from the sun, binary stellar systems, variable stars, stellar clusters, main sequence stars, and other galaxies. It has been, however, more difficult to develop satisfactory methods to determine accurate distances to the more than 1000 planetary nebulae that have been discovered in our galaxy.

scholarly journals A SPITZER SURVEY OF YOUNG STELLAR CLUSTERS WITHIN ONE KILOPARSEC OF THE SUN: CLUSTER CORE EXTRACTION AND BASIC STRUCTURAL ANALYSIS

2009 ◽  
Vol 184 (1) ◽  
pp. 18-83 ◽  
Author(s):  
R. A. Gutermuth ◽  
S. T. Megeath ◽  
P. C. Myers ◽  
L. E. Allen ◽  
J. L. Pipher ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Cluster Core ◽  
The Sun ◽  
Stellar Clusters ◽  
Core Extraction

Lone Rovers

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Planetary Systems ◽  
Albert Einstein ◽  
Interstellar Space ◽  
The Sun ◽  
Stellar Clusters ◽  
Gravitational Lenses ◽  
Supernova Explosions

How do stars and planets break the bonds of gravity, and how do we know they do? Most stars form with hundreds, if not thousands, of nearby neighbors, and yet the Sun is all alone; we learn about its crowded birthplace from decayed radioactive products and by the examples of stellar clusters all around in which supernova explosions can either trigger starbirth or terminate the growth of planetary systems. Planets form as the entourage of stars, and yet many have been found floating freely in interstellar space; such dark bodies, thrown free from their original planetary systems by migrating sibling planets and now drifting far from stars, are found by their bending of starlight, working as gravitational lenses—as predicted by Albert Einstein—when they pass in front of distant stars.

scholarly journals The largest molecular complexes in the first Galactic quadrant

1985 ◽  
Vol 106 ◽  
pp. 303-304
Author(s):  
T. M. Dame ◽  
B. G. Elmegreen ◽  
R. S. Cohen ◽  
P. Thaddeus
Keyword(s):  
Large Scale ◽  
Molecular Complexes ◽  
Hii Regions ◽  
Large Scale Structure ◽  
The Sun ◽  
Stellar Clusters ◽  
Orion Nebula ◽  
The Galaxy ◽  
Co Emission ◽  
Stellar Clusters And Associations

The CO emission within a few kiloparsecs of the Sun is dominated by a small number of very large molecular complexes, including those associated with the Orion Nebula (Thaddeus 1982), M16 and M17 (Elmegreen, Lada, and Dickinson 1979), and NGC7538 (Cohen et al. 1980). These complexes have masses from several 105 to 106 M⊙ and are generally very well-defined objects. They are also well endowed with HII regions, stellar clusters and associations, masers, and other Population-I objects whose distances can be measured. The complexes are thus valuable probes of the large-scale structure of the Galaxy.

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