Massive stars

Vanbeveren, D.; Loore, C. De; Rensbergen, W. Van

doi:10.1007/s001590050015

Cited by 201 publications

(233 citation statements)

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“…If HD 206267 is an O6.5 V star (Walborn & Panek 1984), then its lifetime in the main sequence is ∼6×10 6 yr (e.g. Vanbeveren et al 1998), which roughly agrees with the times given above. On the other hand, the globule shows the clear signature of much younger stars and protostars, and the dynamical timescales estimated from the jets (see Sect.…”

Section: The Stellar Populationsupporting

confidence: 84%

The stellar population and complex structure of the bright-rimmed cloud IC 1396N

Beltrán¹,

Massi

López

et al. 2009

A&A

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Context. IC 1396N is a bright-rimmed cloud associated with an intermediate-mass star-forming region, where a number of HerbigHaro objects, H 2 jet-like features, CO molecular outflows, and millimeter compact sources have been observed. Aims. We study the complex structure of the IC 1396N core and the molecular outflows detected in the region in detail and reveal the presence of additional YSOs inside this globule. Methods. We carried out a deep survey of the IC 1396N region in the J, H, K broadband filters and deep high-angular resolution observations in the H 2 narrowband filter with NICS at the TNG telescope. The completeness limits in the 2MASS standard are K s ∼ 17.5, H ∼ 18.5, and J ∼ 19.5. Results. A total of 736 sources have been detected in all three bands within the area where the JHK images overlap. There are 128 sources detected only in HK , 67 detected only in K , and 79 detected only in JH. We found only a few objects exhibiting a near-infrared excess and no clear signs of clustering of sources towards the southern rim. In the case of triggered star formation in the southern rim of the globule, this could be very recent, because it is not shown through Near-Infrared imaging alone. The H 2 emission is complex and knotty and shows a large number of molecular hydrogen features spread over the region, testifying to recent starformation activity throughout the whole globule. This emission is resolved into several chains or groups of knots that sometimes show a jet-like morphology. The shocked cloudlet model scenario previously proposed to explain the V-shaped morphology of the CO molecular outflow powered by the intermediate-mass YSO BIMA 2 seems to be confirmed by the presence of H 2 emission at the position of the deflecting western clump. New possible flows have been discovered in the globule, and some of them could be very long. In particular, the YSO BIMA 3 could be powering an old and poorly collimated outflow.

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Section: The Stellar Populationsupporting

confidence: 84%

The stellar population and complex structure of the bright-rimmed cloud IC 1396N

Beltrán¹,

Massi

López

et al. 2009

A&A

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“…From the theoretical point of view, it is well known that strong mass loss during the RSG phase favours a bluewards evolution (Salasnich et al 1999;Vanbeveren et al 1998Vanbeveren et al , 2007 and thus helps in fulfilling one of the two minimal conditions for having a WR star, namely to have an effective temperature higher than about log(T eff /K) = 4.0. However, it is unclear whether this strong mass loss may lead to the formation of WC stars.…”

Section: Discussion Of Various Possible Origins For the Low-luminositmentioning

confidence: 99%

Grids of stellar models with rotation

Georgy

Ekström

Meynet

et al. 2012

A&A

299

364

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Context. In recent years, many very interesting observations have appeared concerning the positions of Wolf-Rayet (WR) stars in the Hertzsprung-Russell diagram (HRD), the number ratios of WR stars, the nature of Type Ibc supernova (SN) progenitors, long and soft gamma ray bursts (LGRB), and the frequency of these various types of explosive events. These observations represent key constraints on massive star evolution. Aims. We study, in the framework of the single-star evolutionary scenario, how rotation modifies the evolution of a given initial mass star towards the WR phase and how it impacts the rates of Type Ibc SNe. We also discuss the initial conditions required to obtain collapsars and LGRB. Methods. We used a recent grid of stellar models computed with and without rotation to make predictions concerning the WR populations and the frequency of different types of core-collapse SNe. Current rotating models were checked to provide good fits to the following features: solar luminosity and radius at the solar age, main-sequence width, red-giant and red-supergiant (RSG) positions in the HRD, surface abundances, and rotational velocities. Results. Rotating stellar models predict that about half of the observed WR stars and at least half of the Type Ibc SNe may be produced through the single-star evolution channel. Rotation increases the duration of the WNL and WNC phases, while reducing those of the WNE and WC phases, as was already shown in previous works. Rotation increases the frequency of Type Ic SNe. The upper mass limit for Type II-P SNe is ∼19.0 M for the non rotating models and ∼16.8 M for the rotating ones. Both values agree with observations. Moreover, present rotating models provide a very good fit to the progenitor of SN 2008ax. We discuss future directions of research for further improving the agreement between the models and the observations. We conclude that the mass-loss rates in the WNL and RSG phases are probably underestimated at present. We show that up to an initial mass of 40 M , a surface magnetic field inferior to about 200 G may be sufficient to produce some braking. Much lower values are needed at the red supergiant stage. We suggest that the presence/absence of any magnetic braking effect may play a key role in questions regarding rotation rates of young pulsars and the evolution leading to LGRBs.

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“…The chemical abundances (by mass) are color-coded in blue (H), red (He), and gray (metals). (Giannone 1967;Vanbeveren et al 1998;Salasnich et al 1999;Yoon & Cantiello 2010;Georgy 2012;Meynet et al 2013). …”

Section: Linking the Interior Properties Of Sn Progenitors And Their mentioning

confidence: 99%

Fundamental properties of core-collapse supernova and GRB progenitors: predicting the look of massive stars before death

Groh

Meynet

Georgy

et al. 2013

A&A

193

223

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We investigate the fundamental properties of core-collapse supernova (SN) progenitors from single stars at solar metallicity. For this purpose, we combine Geneva stellar evolutionary models with initial masses of M ini = 20−120 M with atmospheric and wind models using the radiative transfer code CMFGEN. We provide synthetic photometry and high-resolution spectra of hot stars at the pre-SN stage. For models with M ini = 9−20 M , we supplement our analysis using publicly available MARCS model atmospheres of RSGs to estimate their synthetic photometry. We employ well-established observational criteria of spectroscopic classification and find that, depending on their initial mass and rotation, massive stars end their lives as red supergiants (RSG), yellow hypergiants (YHG), luminous blue variables (LBV), and Wolf-Rayet (WR) stars of the WN and WO spectral types. For rotating models, we obtained the following types of SN progenitors:, and RSGs (9 ≤ M ini ≤ 18 M ). For non-rotating models, we found spectral types WO1-, and RSGs (9 ≤ M ini ≤ 20 M ). Our rotating models indicate that SN IIP progenitors are all RSG, SN IIL/b progenitors are 56% LBVs and 44% YHGs, SN Ib progenitors are 96% WN10-11 and 4% WOs, and SN Ic progenitors are all WO stars. We find that the most massive and luminous SN progenitors are not necessarily the brightest ones in a given filter, since this depends on their luminosity, temperature, wind density, and the way the spectral energy distribution compares to a filter bandpass. We find that SN IIP progenitors (RSGs) are bright in the RIJHK S filters and faint in the UB filters. SN IIL/b progenitors (LBVs and YHGs), and SN Ib progenitors (WNs) are relatively bright in optical/infrared filters, while SN Ic progenitors (WOs) are faint in all optical filters. We argue that SN Ib and Ic progenitors from single stars should be undetectable in the available pre-explosion images with the current magnitude limits, in agreement with observational results.

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Massive stars

Cited by 201 publications

References 0 publications

The stellar population and complex structure of the bright-rimmed cloud IC 1396N

The stellar population and complex structure of the bright-rimmed cloud IC 1396N

Grids of stellar models with rotation

Fundamental properties of core-collapse supernova and GRB progenitors: predicting the look of massive stars before death

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