A. van de Beek, E. A. J. G Van der Borght and B. P. Vermeulen (eds), Freedom of Religion

Brown, Malcolm

doi:10.1163/17455316-00803015

Cited by 30 publications

(85 citation statements)

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“…Instead, they usually form in clusters (Lada & Lada 2003), associations (e.g. Brown 1994) or in groups that are hierarchically structured (e.g. Sun et al 2017aSun et al ,b, 2018.…”

Section: Sn 2006jcmentioning

confidence: 99%

Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions

Sun

Maund

Hirai

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Type Ibn supernovae (SNe Ibn) are intriguing stellar explosions whose spectra exhibit narrow helium lines with little hydrogen. They trace the presence of circumstellar material (CSM) formed via pre-SN eruptions of their stripped-envelope progenitors. Early work has generally assumed that SNe Ibn come from massive Wolf-Rayet (WR) stars via single star evolution. In this paper, we report ultraviolet (UV) and optical observations of two nearby Type Ibn SNe 2006jc and 2015G conducted with the Hubble Space Telescope (HST) at late times. A point source is detected at the position of SN 2006jc, and we confirm the conclusion of Maund et al. that it is the progenitor's binary companion. Its position on the Hertzsprung-Russell (HR) diagram corresponds to a star that has evolved off the main sequence (MS); further analysis implies a low initial mass for the companion star (M 2 ≤ 12.3 +2.3 −1.5 M ) and a secondary-to-primary initial mass ratio very close to unity (q = M 2 /M 1 ∼ 1); the SN progenitor's hydrogen envelope had been stripped through binary interaction. We do not detect the binary companion of SN 2015G. For both SNe, the surrounding stellar populations have relatively old ages and argue against any massive WR stars as their progenitors. These results suggest that SNe Ibn may have lower-mass origins in interacting binaries. As a result, they also provide evidence that the giant eruptions commonly seen in massive luminous blue variables (LBVs) can also occur in much lower-mass, stripped-envelope stars just before core collapse.

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“…Instead, they usually form in clusters (Lada & Lada 2003), associations (e.g. Brown 1994) or in groups that are hierarchically structured (e.g. Sun et al 2017aSun et al ,b, 2018.…”

Section: Sn 2006jcmentioning

confidence: 99%

Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions

Sun

Maund

Hirai

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The 'Magnetic' column lists which stars have confirmed magnetic field detections (M), and which stars we consider to be non-magnetic (N). The references for distances are the following: a van Leeuwen (2007, Hipparcos ); b de Zeeuw et al (1999); c Sylvester et al (1996); d Brown, de Geus & de Zeeuw (1994); e Dolan & Mathieu (2001); f Vieira et al (2003). The luminosity for HD 190073 was taken from Catala et al (2007) When good quality fits to the observations were obtainable, fitting of T eff and log g for the metallic spectra was included in our determination.…”

Section: F U N Da M E N Ta L Pa R a M E T E R Smentioning

confidence: 99%

Chemical abundances of magnetic and non-magnetic Herbig Ae/Be stars

Folsom¹,

Bagnulo²,

Wade³

et al. 2012

Monthly Notices of the Royal Astronomical Society

105

173

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The photospheres of about 10–20 per cent of main‐sequence A‐ and B‐type stars exhibit a wide range of chemical peculiarities, often associated with the presence of a magnetic field. It is not exactly known at which stage of stellar evolution these chemical peculiarities develop. To investigate this issue, in this paper we study the photospheric compositions of a sample of Herbig Ae and Be stars, which are considered to be the pre‐main‐sequence progenitors of A and B stars. We have performed a detailed abundance analysis of 20 Herbig stars (three of which have confirmed magnetic fields), and one dusty young star. We have found that half the stars in our sample show λ Boötis (λ Boo) chemical peculiarities to varying degrees, only one star shows weak Ap/Bp peculiarities and all the remaining stars are chemically normal. The incidence of λ Boo chemical peculiarities we find in Herbig stars is much higher than what is seen on the main sequence. We argue that a selective accretion model for λ Boo star formation is a natural explanation for the remarkably large number of λ Boo stars in our sample. We also find that the magnetic Herbig stars do not exhibit a range of chemical compositions remarkably different from the normal stars: one magnetic star displays λ Boo chemical peculiarities (HD 101412), one displays weak Ap/Bp peculiarities (V380 Ori A) and one (HD 190073) is chemically normal. This is completely different from what is seen on the main sequence, where all magnetic A and cool B stars show Ap/Bp chemical peculiarities, and this is consistent with the idea that the magnetic field precedes the formation of the chemical peculiarities typical of Ap and Bp stars.

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“…For NGC 2071 and NGC 2024, parameters from past mass estimates (Nutter & Ward-Thompson 2007) were used to calculate source masses. A distance of 400 pc was assumed for both regions (Brown, de Geus & de Zeeuw 1994) and a temperature of 20 K was assumed as an estimate of the dust temperature (Launhardt et al 1996;Mitchell et al 2001;Johnstone & Bally 2006). An 850 μm dust opacity of 0.01 cm 2 g −1 was used (Andre, Ward-Thompson & Motte 1996;Ward-Thompson, Motte & Andre 1999;André et al 2003), similar to the dust opacity used for NGC 1333.…”

Section: Mass Calculations For Ngc 2071 and Ngc 2024mentioning

confidence: 99%

Molecular line contamination in the SCUBA-2 450 and 850 μm continuum data

Drabek¹,

Hatchell²,

Friberg

et al. 2012

Monthly Notices of the Royal Astronomical Society

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Observations of the dust emission using millimetre/submillimetre bolometer arrays can be contaminated by molecular line flux, such as flux from 12CO. As the brightest molecular line in the submillimetre, it is important to quantify the contribution of CO flux to the dust continuum bands. Conversion factors were used to convert molecular line integrated intensities to flux detected by bolometer arrays in mJy beam−1. These factors were calculated for 12CO line integrated intensities to the SCUBA‐2 850 and 450 μm bands. The conversion factors were then applied to HARP 12CO 3–2 maps of NGC 1333 in the Perseus complex and NGC 2071 and NGC 2024 in the Orion B molecular cloud complex to quantify the respective 12CO flux contribution to the 850 μm dust continuum emission. Sources with high molecular line contamination were analysed in further detail for molecular outflows and heating by nearby stars to determine the cause of the 12CO contribution. The majority of sources had a 12CO 3–2 flux contribution under 20 per cent. However, in regions of molecular outflows, the 12CO can dominate the source dust continuum (up to 79 per cent contamination) with 12CO fluxes reaching ∼68 mJy beam−1.

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A. van de Beek, E. A. J. G Van der Borght and B. P. Vermeulen (eds), Freedom of Religion

Cited by 30 publications

References 0 publications

Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions

Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions

Chemical abundances of magnetic and non-magnetic Herbig Ae/Be stars

Molecular line contamination in the SCUBA-2 450 and 850 μm continuum data

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