Direct Analysis of Spectra of Type Ib Supernovae

Branch, David; Benetti, S.; Kasen, Daniel; Baron, E.; Jeffery, David J.; Hatano, K.; Stathakis, R. A.; Filippenko, A. V.; Matheson, T.; Pastorello, A.; Altavilla, G.; Cappellaro, E.; Rizzi, L.; Turatto, M.; Li, Weidong; Leonard, Douglas C.; Shields, J. C.

doi:10.1086/338127

Cited by 175 publications

(285 citation statements)

References 35 publications

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“…In both Type IIb and Ib SNe, the metal and helium emission lines are significantly broader than in Type IIP SNe, as there is little or no hydrogen in the ejecta to take up the explosion energy. Type IIb and Type Ib SNe have similar light curves and spectral evolution (Woosley et al 1994;Filippenko et al 1994), a similarity further strengthened by evidence of trace hydrogen in many Type Ib SNe (Branch et al 2002;Elmhamdi et al 2006).…”

Section: Introductionmentioning

confidence: 75%

Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

Jerkstrand

Ergon

Smartt

et al. 2014

A&A

151

249

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We investigate line formation processes in Type IIb supernovae (SNe) from 100 to 500 days post-explosion using spectral synthesis calculations. The modelling identifies the nuclear burning layers and physical mechanisms that produce the major emission lines, and the diagnostic potential of these. We compare the model calculations with data on the three best observed Type IIb SNe to-date − SN 1993J, SN 2008ax, and SN 2011dh. Oxygen nucleosynthesis depends sensitively on the main-sequence mass of the star and modelling of the [O I] λλ6300, 6364 lines constrains the progenitors of these three SNe to the M ZAMS = 12−16 M range (ejected oxygen masses 0.3−0.9 M ), with SN 2011dh towards the lower end and SN 1993J towards the upper end of the range. The high ejecta masses from M ZAMS 17 M progenitors give rise to brighter nebular phase emission lines than observed. Nucleosynthesis analysis thus supports a scenario of low-to-moderate mass progenitors for Type IIb SNe, and by implication an origin in binary systems. We demonstrate how oxygen and magnesium recombination lines may be combined to diagnose the magnesium mass in the SN ejecta. For SN 2011dh, a magnesium mass of 0.02−0.14 M is derived, which gives a Mg/O production ratio consistent with the solar value. Nitrogen left in the He envelope from CNO burning gives strong [N II] λλ6548, 6583 emission lines that dominate over Hα emission in our models. The hydrogen envelopes of Type IIb SNe are too small and dilute to produce any noticeable Hα emission or absorption after ∼150 days, and nebular phase emission seen around 6550 Å is in many cases likely caused by [N II] λλ6548, 6583. Finally, the influence of radiative transport on the emergent line profiles is investigated. Significant line blocking in the metal core remains for several hundred days, which affects the emergent spectrum. These radiative transfer effects lead to early-time blueshifts of the emission line peaks, which gradually disappear as the optical depths decrease with time. The modelled evolution of this effect matches the observed evolution in SN 2011dh.

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Section: Introductionmentioning

confidence: 75%

Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

Jerkstrand

Ergon

Smartt

et al. 2014

A&A

151

249

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“…The velocity increased slowly with time, reaching ∼ 7, 000 km s −1 (Fig. 3), an unusual behavior for SN Ib (see, e.g., Branch et al 2002). On the contrary, the velocities of the Fe lines declined with time.…”

Section: Light Curve Modelsmentioning

confidence: 83%

The Unique Type Ib Supernova 2005bf: A WN Star Explosion Model for Peculiar Light Curves and Spectra

Tominaga

Tanaka

Nomoto

et al. 2005

ApJ

103

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Observations and modeling for the light curve (LC) and spectra of supernova (SN) 2005bf are reported. This SN showed unique features: the LC had two maxima, and declined rapidly after the second maximum, while the spectra showed strengthening He lines whose velocity increased with time. The double-peaked LC can be reproduced by a double-peaked 56 Ni distribution, with most 56 Ni at low velocity and a small amount at high velocity. The rapid post-maximum decline requires a large fraction of the γ-rays to escape from the 56 Ni-dominated region, possibly because of low-density "holes". The presence of Balmer lines in the spectrum suggests that the He layer of the progenitor was substantially intact. Increasing γ-ray deposition in the He layer due to enhanced γ-ray escape from the 56 Ni-dominated region may explain both the delayed strengthening and the increasing velocity of the He lines. The SN has massive ejecta (∼ 6−7M ⊙ ), normal kinetic energy (∼ 1.0 − 1.5 × 10 51 ergs), high peak bolometric luminosity (∼ 5 × 10 42 erg s −1 ) for an epoch as late as ∼ 40 days, and a large 56 Ni mass (∼ 0.32M ⊙ ). These properties, and the presence of a small amount of H suggest that the progenitor was initially massive (M∼ 25 − 30M ⊙ ) and had lost most of its H envelope, and was possibly a WN star. The double-peaked 56 Ni distribution suggests that the explosion may have formed jets that did not reach the He layer. The properties of SN 2005bf resemble those of the explosion of Cassiopeia A.

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“…Benetti et al (2000) classified SN 2000H a type IIb supernova because of the hydrogen lines observed in the spectrum. However, these hydrogen lines were not obvious and the light curve showed more resemblance with a SN Ib (Branch et al 2002). Therefore, this supernova has been classified by other authors as a type Ib supernova (Branch et al 2002;Elmhamdi et al 2006).…”

Section: Sn 1996cbmentioning

confidence: 85%

Binary progenitor models of type IIb supernovae

Claeys

Mink

Pols

et al. 2011

A&A

120

147

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Massive stars that lose their hydrogen-rich envelope down to a few tenths of a solar mass explode as extended type IIb supernovae, an intriguing subtype that links the hydrogen-rich type II supernovae with the hydrogen-poor type Ib and Ic. The progenitors may be very massive single stars that lose their envelope due to their stellar wind, but mass stripping due to interaction with a companion star in a binary system is currently considered to be the dominant formation channel. Anticipating the upcoming automated transient surveys, we computed an extensive grid of binary models with the Eggleton binary evolution code. We identify the limited range of initial orbital periods and mass ratios required to produce type IIb binary progenitors. The rate we predict from our standard models, which assume conservative mass transfer, is about six times smaller than the current rate indicated by observations. It is larger but still comparable to the rate expected from massive single stars. We evaluate extensively the effect of various assumptions such as the adopted accretion efficiency, the binary fraction and distributions for the initial binary parameters. To recover the observed rate we must generously allow for uncertainties and consider low accretion efficiencies in combination with limited angular momentum loss from the system. Motivated by the claims of detection and non-detection of companions for a few IIb supernovae, we investigate the properties of the secondary star at the moment of explosion. We identify three cases: (1) the companion is predicted to appear as a hot O star in about 90% of the cases, as a result of mass accretion during its main sequence evolution, (2) the companion becomes an over-luminous B star in about 3% of the cases, if mass accretion occurred while crossing the Hertzsprung gap or (3) in systems with very similar initial masses the companion will appear as a K supergiant. The second case, which applies to the well-studied case of SN 1993J and possibly to SN 2001ig, is the least common case and requires that the companion very efficiently accretes the transferred material -in contrast to what is required to recover the overall IIb rate. We note that relative rates quoted above depend on the assumed efficiency of semi-convective mixing: for inefficient semi-convection the presence of blue supergiant companions is expected to be more common, occurring in up to about 40% of the cases. Our study demonstrates that type IIb supernovae have the potential to teach us about the physics of binary interaction and about stellar processes such as internal mixing and possibly stellar-wind mass loss. The fast increasing number of type IIb detections from automated surveys may lead to more solid constraints on these model uncertainties in the near future.

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Direct Analysis of Spectra of Type Ib Supernovae

Cited by 175 publications

References 35 publications

Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

The Unique Type Ib Supernova 2005bf: A WN Star Explosion Model for Peculiar Light Curves and Spectra

Binary progenitor models of type IIb supernovae

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