scholarly journals The chemical composition of Galactic ring nebulae around massive stars

2016 ◽  
Vol 460 (4) ◽  
pp. 4038-4062 ◽  
Author(s):  
C. Esteban ◽  
A. Mesa-Delgado ◽  
C. Morisset ◽  
J. García-Rojas
Keyword(s):  
Chemical Composition ◽  
Massive Stars ◽  
Ring Nebulae

scholarly journals Searching for self-enrichment in Cygnus OB2

2016 ◽  
Vol 12 (S329) ◽  
pp. 386-386
Author(s):  
Sara R. Berlanas ◽  
Artemio Herrero ◽  
Fernando Comerón ◽  
Anna Pasquali ◽  
Sergio Simón-Díaz
Keyword(s):  
Chemical Composition ◽  
Interstellar Medium ◽  
Massive Stars ◽  
Composition Gradient ◽  
Successive Generations ◽  
Galactic Longitude

Cygnus OB2 is a rich and relatively close (d~1.4 kpc) OB association in our Galaxy. It represents an ideal testbed for our theories about self-enrichment processes produced by pollution of the interstellar medium by successive generations of massive stars. Comerón & Pasquali (2012, A&A, 543, A101) found a correlation between the age of young stellar groups in Cygnus OB2 and their Galactic longitude. If is associated with a chemical composition gradient, it could support these self-enrichment processes.

scholarly journals Molecular gas associated with Wolf-Rayet ring nebulae

1999 ◽  
Vol 193 ◽  
pp. 370-371 ◽  
Author(s):  
Anthony P. Marston ◽  
Jaydene T. Welzmiller ◽  
Mark A. Bransford ◽  
John H. Black ◽  
P. Bergman
Keyword(s):  
Emission Line ◽  
Massive Stars ◽  
Molecular Gas ◽  
Molecular Materials ◽  
Ionized Gas ◽  
Ring Nebulae ◽  
Gas Component

We present the first 12CO 1→0 emission-line maps of the vicinities of two Wolf-Rayet stars (WR 16 and WR 75) and their associated ring nebulae. We illustrate that sizeable amounts of molecular gas appear associated with these ring nebulae and therefore that the mass of gas in ring nebulae is significantly higher than inferred from observations of the ionized gas component alone. We discuss the possible stellar and interstellar origins of these molecular materials and the implications for the evolution of massive stars up to the WR phase.

scholarly journals Radio observations of interstellar bubbles surrounding massive stars

2003 ◽  
Vol 212 ◽  
pp. 596-603 ◽  
Author(s):  
Cristina E. Cappa ◽  
E. Marcelo Arnal ◽  
Silvina Cichowolski ◽  
W. Miller Goss ◽  
Serge Pineault
Keyword(s):  
Massive Stars ◽  
Radio Continuum ◽  
Radio Observations ◽  
Ring Nebulae

We show radio continuum observations of the WR ring nebulae around WR 101 and WR 113 obtained using the VLA and H i 21 cm line data of the interstellar bubble around the O type stars BD +24° 3866 and BD+25° 3952 obtained with the DRAO Synthesis Telescope. We review previous radio continuum and H i line results toward WR and O-type stars.

Formation of Ring Nebulae around Massive Stars in LMC HII Regions

1999 ◽  
Vol 190 ◽  
pp. 134-135
Author(s):  
Kerstin Weis ◽  
Wolfgang J. Duschl
Keyword(s):  
Main Sequence ◽  
Massive Stars ◽  
Ambient Medium ◽  
Hii Regions ◽  
Large Magellanic Cloud ◽  
High Mass ◽  
Stellar Winds ◽  
High Mass Loss ◽  
Form Ring ◽  
Ring Nebulae

Massive stars have strong stellar winds and consequently a high mass loss during their lifetimes. Therefore they can form ring nebulae by stellar winds sweeping up the ambient medium in the main sequence phase or through wind-wind interaction or eruptions in the evolved state. We present preliminary results of a search for single bubbles and ring-nebulae around massive stars in the Large Magellanic Cloud (LMC).

scholarly journals LMC Clusters: Young

1980 ◽  
Vol 85 ◽  
pp. 317-323 ◽  
Author(s):  
K. C. Freeman
Keyword(s):  
Chemical Composition ◽  
Age Structure ◽  
Total Mass ◽  
Globular Clusters ◽  
Massive Stars ◽  
Mass Range ◽  
Stellar Mass ◽  
Stellar Content ◽  
The Galaxy ◽  
Mass Functions

The young globular clusters of the LMC have ages of 107–108 y. Their masses and structure are similar to those of the smaller galactic globular clusters. Their stellar mass functions (in the mass range 6 m⊙ to 1.2 m⊙) vary greatly from cluster to cluster, although the clusters are similar in total mass, age, structure and chemical composition. It would be very interesting to know why these clusters are forming now in the LMC and not in the Galaxy.I will talk about the “young globular” or “blue populous” clusters of the LMC. They were first identified as a family by Hodge (1961). The ages of these objects are 107 to 108 y, and their masses are 104 to 105 m⊙, so they are populous enough to be really useful for studying the evolution of massive stars. I will not discuss this aspect (see the extensive work by Flower and Hodge and Robertson since 1974), but will concentrate on the structure and stellar content of these young clusters.

scholarly journals Ring Nebulae Around Massive Stars

1991 ◽  
Vol 143 ◽  
pp. 349-364
Author(s):  
You-Hua Chu
Keyword(s):  
Stellar Evolution ◽  
Spectral Properties ◽  
Massive Stars ◽  
Ambient Medium ◽  
Stellar Winds ◽  
Luminous Blue Variables ◽  
Stellar Properties ◽  
Ring Nebulae ◽  
Central Stars ◽  
Temperature Correlations

Ring nebulae have been found around WR stars, OB and Of stars, and luminous blue variables. Ring nebulae are formed by the interaction between the central stars and their ambient medium via different combinations of stellar winds, ejecta, and radiation. The spectral properties of the nebulae can be used to diagnose the stellar properties, such as luminosity and effective temperature. Correlations between ring nebulae and their central stars may be used to check scenarios of stellar evolution.

scholarly journals An observational asteroseismic study of the pulsating B-type stars in the open cluster NGC 884

2013 ◽  
Vol 9 (S301) ◽  
pp. 479-480
Author(s):  
S. Saesen ◽  
M. Briquet ◽  
C. Aerts ◽  
A. Miglio ◽  
F. Carrier
Keyword(s):  
Chemical Composition ◽  
Recent Progress ◽  
Massive Stars ◽  
Open Cluster ◽  
Seismic Interpretation ◽  
Evolution Model ◽  
Stellar Structure ◽  
Current Status ◽  
Physical Description ◽  
Young Open Cluster

AbstractRecent progress in the seismic interpretation of field β Cep stars has resulted in improvements of the physical description in the stellar structure and evolution model computations of massive stars. Further asteroseismic constraints can be obtained from studying ensembles of stars in a young open cluster, which all have similar age, distance and chemical composition. We present an observational asteroseismic study based on the discovery of numerous multi-periodic and mono-periodic B-type stars in the open cluster NGC 884 (χ Persei). Our study illustrates the current status of ensemble asteroseismology of this young open cluster.

scholarly journals Chemical Composition of the Galactic Bulge in Baade's Window

2009 ◽  
Vol 5 (S265) ◽  
pp. 279-284 ◽  
Author(s):  
Andrew McWilliam ◽  
Jon Fulbright ◽  
R. Michael Rich
Keyword(s):  
Chemical Composition ◽  
Massive Stars ◽  
Galactic Bulge ◽  
Rapid Formation ◽  
The Mean ◽  
Red Clump

Abstract1. McWilliam and Zoccali (2009) show the existence of two Red Clump populations towards the Galactic bulge, based on 2MASS data. 2.Measured [Mg/Fe], [Al/Fe], and [La/Eu] ratios in the bulge are consistent with a rapid formation timescale (<1Gyr), which also requires a slightly top-heavy IMF to reproduce the mean bulge metallicity. The [C/O] and [O/Fe] ratios are consistent if their predicted metal-dependent yields from massive stars with winds are considered. The decline in explosive [α/Fe] (Si, Ca, and Ti) can only be understood if their yields also decline with metallicity above [Fe/H]~−1.

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