scholarly journals SOAR OPTICAL AND NEAR-INFRARED SPECTROSCOPIC SURVEY OF NEWLY DISCOVERED MASSIVE STARS IN THE PERIPHERY OF GALACTIC MASSIVE STAR CLUSTERS I-NGC 3603

2016 ◽  
Vol 823 (2) ◽  
pp. 96 ◽  
Author(s):  
A. Roman-Lopes ◽  
G. A. P. Franco ◽  
D. Sanmartim
Keyword(s):  
Massive Star ◽  
Near Infrared ◽  
Massive Stars ◽  
Star Clusters ◽  
Infrared Spectroscopic

scholarly journals The influence of feedback from massive stars on the formation and emergence of massive clusters

2015 ◽  
Vol 12 (S316) ◽  
pp. 177-183
Author(s):  
James E. Dale
Keyword(s):  
Large Scale ◽  
Massive Star ◽  
Massive Stars ◽  
Cluster Structure ◽  
Star Clusters ◽  
Stellar Feedback ◽  
Making Sense ◽  
Formation Efficiency ◽  
Massive Clusters ◽  
Made In

AbstractMassive star clusters are of fundamental importance both observationally, since they are visible at such great distances, and theoretically, because of their influence on the large–scale ISM. Understanding stellar feedback is a prerequisite for making sense of their formation and early evolution, since feedback influences cluster structure, star formation efficiency, and sets the timescales on which clusters emerge from their parent clouds to become optically visible. I review the progress made in understanding these issues from a numerical perspective.

scholarly journals Searching for emission line and OB stars in Cl 1806-20 using a NIR narrow-band technique

2010 ◽  
Vol 6 (S272) ◽  
pp. 606-607 ◽  
Author(s):  
Michelle L. Edwards ◽  
Reba M. Bandyopadhyay ◽  
Stephen S. Eikenberry ◽  
Valerie J. Mikles ◽  
Dae-Sik Moon
Keyword(s):  
Emission Line ◽  
Massive Star ◽  
Near Infrared ◽  
Narrow Band ◽  
Massive Stars ◽  
Narrow Band Imaging ◽  
Ob Stars ◽  
Luminous Blue Variables ◽  
Upper Limit

AbstractWe survey the environment of Cl 1806-20 using near-infrared narrow-band imaging to search for Brγ features indicative of evolved massive stars. Using this technique, we successfully detect previously identified massive stars in the cluster. We detect no new emission line stars, establishing a firm upper limit on the number of Wolf Rayets and Luminous Blue Variables; however, we do find several candidate OB supergiants, which likely represent the bulk of the heretofore undiscovered massive star population.

scholarly journals Spectroscopy of the Ionizing Sources of UC HII Regions

2002 ◽  
Vol 12 ◽  
pp. 167-169
Author(s):  
Margaret M. Hanson
Keyword(s):  
Near Infrared ◽  
Massive Stars ◽  
Hii Regions ◽  
Spectroscopic Studies ◽  
Physical Conditions ◽  
Early Stages ◽  
Infrared Spectroscopic

AbstractThe utility of near-infrared, spectroscopic studies of central ionizing sources of UC HII regions is presented, in conjunction with a recently available, sophisticated atmospheric code, to constrain the physical conditions and environment of very massive stars at extremely early stages of evolution.

scholarly journals On the early evolution of massive star clusters: the case of cloud D1 and its embedded cluster in NGC 5253

2020 ◽  
Vol 494 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Sergiy Silich ◽  
Guillermo Tenorio-Tagle ◽  
Sergio Martínez-González ◽  
Jean Turner
Keyword(s):  
Massive Star ◽  
Massive Stars ◽  
Star Clusters ◽  
Early Evolution ◽  
Mass Loading ◽  
Low Mass Stars ◽  
Stellar Cluster ◽  
Star Forming ◽  
Cluster Phase ◽  
Protostellar Discs

ABSTRACT We discuss a theoretical model for the early evolution of massive star clusters and confront it with the ALMA, radio, and infrared observations of the young stellar cluster highly obscured by the molecular cloud D1 in the nearby dwarf spheroidal galaxy NGC 5253. We show that a large turbulent pressure in the central zones of D1 cluster may cause individual wind-blown bubbles to reach pressure confinement before encountering their neighbours. In this case, stellar winds energy is added to the hot shocked wind pockets of gas around individual massive stars that leads them to meet and produce a cluster wind in time-scales less than 105 yr. In order to inhibit the possibility of cloud dispersal, or the early negative star formation feedback, one should account for mass loading that may come, for example, from pre-main-sequence (PMS) low-mass stars through photoevaporation of their protostellar discs. Mass loading at a rate in excess of 8 × 10−9 M⊙ yr−1 per each PMS star is required to extend the hidden star cluster phase in this particular cluster. In this regime, the parental cloud remains relatively unperturbed, while pockets of molecular, photoionized and hot gas coexist within the star-forming region. Nevertheless, the most likely scenario for cloud D1 and its embedded cluster is that the hot shocked winds around individual massive stars should merge at an age of a few million of years when the PMS star protostellar discs vanish and mass loading ceases that allows a cluster to form a global wind.

scholarly journals Massive Stars in the Galactic Center

2007 ◽  
Vol 3 (S250) ◽  
pp. 257-264
Author(s):  
F. Martins ◽  
D. J. Hillier ◽  
R. Genzel ◽  
F. Eisenhauer ◽  
T. Ott ◽  
...  
Keyword(s):  
Massive Star ◽  
Near Infrared ◽  
Galactic Center ◽  
Massive Stars ◽  
Evolutionary Status ◽  
Infrared Spectral Range ◽  
Different Types ◽  
Infrared Spectral ◽  
Observational Techniques ◽  
Massive Clusters

AbstractWe present results of two studies aiming at better understanding the properties of massive stars in the Galactic Center. We focus on the youngest and oldest of the three massive clusters harboring this region, namely the Arches and central cluster. We show that the development of powerful observational techniques in the near infrared spectral range (mainly 3D spectroscopy) allows to uncover the entire massive star population in these clusters. Using CMFGEN models, we derive the classical stellar and wind properties of 46 stars, as well as their surface abundances. The latter allow us to investigate in detail their evolutionary status and to identify evolutionary sequences between different types of stars. We thus constrain stellar evolution in the upper part of the HR diagram.

scholarly journals Stellar content of obscured compact H II regions

2003 ◽  
Vol 212 ◽  
pp. 467-473 ◽  
Author(s):  
Margaret M. Hanson ◽  
Lex Kaper ◽  
Arjan Bik ◽  
Fernando Comerón ◽  
Joachim Puls ◽  
...  
Keyword(s):  
Massive Star ◽  
Near Infrared ◽  
Massive Stars ◽  
Model Atmosphere ◽  
Spectroscopic Studies ◽  
H Ii Regions ◽  
Stellar Content ◽  
High Quality ◽  
Physical Conditions

Near-infrared, spectroscopic studies of central ionizing sources of very young H ii regions is presented in conjunction with a recently available, sophisticated atmospheric code to constrain the physical conditions and environment of very massive stars at very early stages of evolution. Combining high quality near-infrared spectroscopy of very young massive stars with model atmosphere calculations should allow for the most accurate quantitative determination of Teff, rotation, L, and log g, and to search for binaries and possible disk or in-fall signatures in forming or recently formed massive stars. These characteristics make up a vital boundary condition constraining theories on massive star formation.

scholarly journals Unveiling the massive stars in the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 230-234 ◽  
Author(s):  
H. Dong ◽  
J. Mauerhan ◽  
M. R. Morris ◽  
Q. D. Wang ◽  
A. Cotera
Keyword(s):  
Massive Star ◽  
Galactic Center ◽  
Massive Stars ◽  
Star Clusters ◽  
Radial Velocities ◽  
Stellar Winds ◽  
Band Spectra

AbstractWe present our recent efforts to unveil and understand the origin of massive stars outside the three massive star clusters in the Galactic center. From our Hubble/NICMOS survey of the Galactic center, we have identified 180 Paschen-α emitting sources, most of which should be evolved massive stars with strong optically thin stellar winds. Recently, we obtained Gemini GNIRS/NIFS H- and K-band spectra of eight massive stars near the Arches cluster. From their radial velocities, ages and masses, we suggest that in our sample, two stars are previous members of the Arches cluster, while other two stars embedded in the H1/H2 Hii regions formed in-situ.

scholarly journals Black Holes and Core Expansion in Massive Star Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 176-180
Author(s):  
A. D. Mackey ◽  
M. I. Wilkinson ◽  
M. B. Davies ◽  
G. F. Gilmore
Keyword(s):  
Black Holes ◽  
Stellar Evolution ◽  
Massive Star ◽  
Massive Stars ◽  
Star Clusters ◽  
Magellanic Clouds ◽  
Core Radius ◽  
Stellar Component ◽  
Rapid Mass ◽  
Dynamical Origin

AbstractMassive star clusters in the Magellanic Clouds are observed to follow a striking trend in size with age – older clusters exhibit a much greater spread in core radius than do younger clusters, which are generally compact. We present results from realistic N-body modelling of massive star clusters, aimed at investigating a dynamical origin for the radius-age trend. We find that stellar-mass black holes, formed as remnants of the most massive stars in a cluster, can constitute a dynamically important population. If retained, these objects rapidly form a dense core where interactions are common, resulting in the scattering of black holes into the cluster halo, and the ejection of black holes from the cluster. These processes heat the stellar component, resulting in prolonged core expansion of a magnitude matching the observations. Core expansion at early times does not result from the action of black holes, but can be reproduced by the effects of rapid mass-loss due to stellar evolution in a primordially mass segregated cluster.

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