Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe expansion of stripped-envelope stars: consequences for supernovae and gravitational-wave progenitors
179
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars loses part or all of its outer envelope and becomes a stripped-envelope star. The evolution of the size of these stripped stars is crucial in determining whether they experience further interactions and their final fate. We present new calculations of stripped-envelope stars based on binary evolution models computed with MESA. We use these to investigate their radius evolution as a function of mass and metallicity. We further discuss their pre-supernova observable characteristics and potential consequences of their evolution on the properties of supernovae from stripped stars. At high metallicity we find that practically all of the hydrogen-rich envelope is removed, in agreement with earlier findings. Only progenitors with initial masses below 10Msun expand to large radii (up to 100Rsun), while more massive progenitors stay compact. At low metallicity, a substantial amount of hydrogen remains and the progenitors can, in principle, expand to giant sizes (> 400Rsun), for all masses we consider. This implies that they can fill their Roche lobe anew. We show that the prescriptions commonly used in population synthesis models underestimate the stellar radii by up to two orders of magnitude. We expect that this has consequences for the predictions for gravitational-wave sources from double neutron star mergers, in particular for their metallicity dependence.
rate research
Read More
We present the complete sample of stripped-envelope supernova (SN) spectra observed by the Lick Observatory Supernova Search (LOSS) collaboration over the last three decades: 888 spectra of 302 SNe, 652 published here for the first time, with 384 spectra (of 92 SNe) having photometrically-determined phases. After correcting for redshift and Milky Way dust reddening and reevaluating the spectroscopic classifications for each SN, we construct mean spectra of the three major spectral subtypes (Types IIb, Ib, and Ic) binned by phase. We compare measures of line strengths and widths made from this sample to the results of previous efforts, confirming that O I {lambda}7774 absorption is stronger and found at higher velocity in Type Ic SNe than in Types Ib or IIb SNe in the first 30 days after peak brightness, though the widths of nebular emission lines are consistent across subtypes. We also highlight newly available observations for a few rare subpopulations of interest.
Stripped-envelope supernovae (Type IIb, Ib, Ic) showing little or no hydrogen are one of the main classes of explosions of massive stars. Their origin and the evolution of their progenitors are not fully understood as yet. Very massive single stars stripped by their own winds ($gtrsim 25-30 M_{odot}$ at solar metallicity) are considered viable progenitors of these events. However, recent 1D core-collapse simulations show that some massive stars may collapse directly onto black holes after a failed explosion, with weak or no visible transient. In this letter, we estimate the effect of direct collapse onto a black hole on the rates of stripped-envelope supernovae that arise from single stars. For this, we compute single star MESA models at solar metallicity and map their final state to their core-collapse outcome following prescriptions commonly used in population synthesis. According to our models, no single stars that have lost their entire hydrogen-rich envelope are able to explode, and only a fraction of progenitors with a thin hydrogen envelope left (IIb progenitor candidates) do, unless we invoke increased wind mass-loss rates. This result increases the existing tension between the single-star scenario for stripped-envelope supernovae and their observed rates and properties. At face value, our results point towards an even higher contribution of binary progenitors for stripped-envelope supernovae. Alternatively, they may suggest inconsistencies in the common practice of mapping different stellar models to core-collapse outcomes and/or higher overall mass loss in massive stars.
The massive star origins for Type IIP supernovae (SNe) have been established through direct detection of their red supergiants progenitors in pre-explosion observations; however, there has been limited success in the detection of the progenitors of H-deficient SNe. The final fate of more massive stars, capable of undergoing a Wolf-Rayet phase, and the origins of Type Ibc SNe remains debated, including the relative importance of single massive star progenitors or lower mass stars stripped in binaries. We present an analysis of the ages and spatial distributions of massive stars around the sites of 23 stripped-envelope SNe, as observed with the Hubble Space Telescope, to probe the possible origins of the progenitors of these events. Using a Bayesian stellar populations analysis scheme, we find characteristic ages for the populations observed within $150,mathrm{pc}$ of the target Type IIb, Ib and Ic SNe to be $log (t) = 7.20$, $7.05$ and $6.57$, respectively. The Type Ic SNe in the sample are nearly all observed within $100,mathrm{pc}$ of young, dense stellar populations. The environment around SN 2002ap is an important exception both in terms of age and spatial properties. These findings may support the hypothesis that stars with $M_{init} > 30M_{odot}$ produce a relatively large proportion of Type Ibc SNe, and that these SN subtypes arise from progressively more massive progenitors. Significantly higher extinctions are derived towards the populations hosting these SNe than previously used in analysis of constraints from pre-explosion observations. The large initial masses inferred for the progenitors are in stark contrast with the low ejecta masses estimated from SN light curves.
We present observations and analysis of 18 stripped-envelope supernovae observed during 2013 -- 2018. This sample consists of 5 H/He-rich SNe, 6 H-poor/He-rich SNe, 3 narrow lined SNe Ic and 4 broad lined SNe Ic. The peak luminosity and characteristic time-scales of the bolometric light curves are calculated, and the light curves modelled to derive 56Ni and ejecta masses (MNi and Mej). Additionally, the temperature evolution and spectral line velocity-curves of each SN are examined. Analysis of the [O I] line in the nebular phase of eight SNe suggests their progenitors had initial masses $<20$ Msun. The bolometric light curve properties are examined in combination with those of other SE events from the literature. The resulting dataset gives the Mej distribution for 80 SE-SNe, the largest such sample in the literature to date, and shows that SNe Ib have the lowest median Mej, followed by narrow lined SNe Ic, H/He-rich SNe, broad lined SNe Ic, and finally gamma-ray burst SNe. SNe Ic-6/7 show the largest spread of Mej, ranging from $sim 1.2 - 11$ Msun, considerably greater than any other subtype. For all SE-SNe $<$Mej$>=2.8pm{1.5}$ Msun which further strengthens the evidence that SE-SNe arise from low mass progenitors which are typically $<5$ Msun at the time of explosion, again suggesting Mzams $<25$ Msun. The low $<$Mej$>$ and lack of clear bimodality in the distribution implies $<30$ Msun progenitors and that envelope stripping via binary interaction is the dominant evolutionary pathway of these SNe.
We explore a new scenario for producing stripped-envelope supernova progenitors. In our scenario, the stripped-envelope supernova is the second supernova of the binary, in which the envelope of the secondary was removed during its red supergiant phase by the impact of the first supernova. Through 2D hydrodynamical simulations, we find that $sim$50-90$%$ of the envelope can be unbound as long as the pre-supernova orbital separation is $lesssim5$ times the stellar radius. Recombination energy plays a significant role in the unbinding, especially for relatively high mass systems ($gtrsim18M_odot$). We predict that more than half of the unbound mass should be distributed as a one-sided shell at about $sim$10-100pc away from the second supernova site. We discuss possible applications to known supernova remnants such as Cassiopeia A, RX J1713.7-3946, G11.2-0.3, and find promising agreements. The predicted rate is $sim$0.35-1$%$ of the core-collapse population. This new scenario could be a major channel for the subclass of stripped-envelope or type IIL supernovae that lack companion detections like Cassiopeia A.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
