Types IIP Research Articles

A sequence of Type Ib, IIb, II-L, and II-P supernovae from binary-star progenitors with varying initial separations

Over the last decade, evidence has accumulated that massive stars do not typically evolve in isolation but instead follow a tumultuous journey with a companion star on their way to core collapse. While Roche-lobe overflow appears instrumental for the production of a large fraction of Type Ib and Ic supernovae (SNe), variations in the initial orbital period, $P_ init $, of massive interacting binaries may also produce a wide diversity of case B, BC, or C systems, with pre-SN stars endowed from minute to massive H-rich envelopes. Focusing here on the explosion of the primary donor star, originally 12.6\ we used radiation hydrodynamics and nonlocal thermodynamic equilibrium time-dependent radiative transfer to document the gas and radiation properties of such SNe, covering Types Ib, IIb, II-L, and II-P. Variations in init $ are the root cause of the wide diversity of our SN light curves, which present single-peak, double-peak, fast-declining, or plateau-like morphologies in the $V$ band. The different ejecta structures, expansion rates, and relative abundances (e.g., H, He, and can lead to a great deal of diversity in terms of spectral line shapes (absorption versus emission strength and width) and evolution. We emphasize that Halpha is a key tracer of these modulations, and that He is an enduring optical diagnostic for the presence of He. Our grid of simulations fares well against representative Type Ib, IIb, and II-P SNe, but interaction with circumstellar material, which is ignored in this work, is likely at the origin of the tension between our Type II-L SN models and observations (e.g., of SN\,2006Y). Remaining discrepancies in the rise time to bolometric maximum of our models call for a proper account of both small-scale and large-scale structures in core-collapse SN ejecta. Discrepant Type II-P SN models, with a high plateau brightness but small spectral line widths, can be fixed by adopting more compact red-supergiant star progenitors.

Constraining High-energy Neutrino Emission from Supernovae with IceCube

Core-collapse supernovae are a promising potential high-energy neutrino source class. We test for correlation between seven years of IceCube neutrino data and a catalog containing more than 1000 core-collapse supernovae of types IIn and IIP and a sample of stripped-envelope supernovae. We search both for neutrino emission from individual supernovae as well as for combined emission from the whole supernova sample, through a stacking analysis. No significant spatial or temporal correlation of neutrinos with the cataloged supernovae was found. All scenarios were tested against the background expectation and together yield an overall p-value of 93%; therefore, they show consistency with the background only. The derived upper limits on the total energy emitted in neutrinos are 1.7 × 1048 erg for stripped-envelope supernovae, 2.8 × 1048 erg for type IIP, and 1.3 × 1049 erg for type IIn SNe, the latter disfavoring models with optimistic assumptions for neutrino production in interacting supernovae. We conclude that stripped-envelope supernovae and supernovae of type IIn do not contribute more than 14.6% and 33.9%, respectively, to the diffuse neutrino flux in the energy range of about [ 103–105] GeV, assuming that the neutrino energy spectrum follows a power-law with an index of −2.5. Under the same assumption, we can only constrain the contribution of type IIP SNe to no more than 59.9%. Thus, core-collapse supernovae of types IIn and stripped-envelope supernovae can both be ruled out as the dominant source of the diffuse neutrino flux under the given assumptions.

ASPHERICITY, INTERACTION, AND DUST IN THE TYPE II-P/II-L SUPERNOVA 2013EJ IN MESSIER 74

ABSTRACT SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad Hα emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.

PTF11iqb: cool supergiant mass-loss that bridges the gap between Type IIn and normal supernovae

PTF11iqb was initially classified as a TypeIIn event caught very early after explosion. It showed narrow Wolf-Rayet (WR) spectral features on day 2, but the narrow emission weakened quickly and the spectrum morphed to resemble those of Types II-L and II-P. At late times, Halpha emission exhibited a complex, multipeaked profile reminiscent of SN1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN~1998S, although with weaker interaction with circumstellar material (CSM) at early times, and stronger CSM interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for weak CSM interaction added to the light curve of a normal SN~II-P. This plateau requires that the progenitor had an extended H envelope like a red supergiant, consistent with the slow progenitor wind speed indicated by narrow emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum --- meaning that the presence of such WR features in an early SN spectrum does not necessarily indicate a WR-like progenitor. [abridged] Overall, PTF11iqb bridges SNe~IIn with weaker pre-SN mass loss seen in SNe II-L and II-P, implying a continuum between these types.

Multi-band optical light-curve behavior of core-collapse supernovae

AbstractWe present survey results obtained from the UBVRI optical photometric follow-up of 19 bright core-collapse SNe during 2002-2012 using 1-m class optical telescopes operated by the Aryabhatta Research Institute of Observational Science (acronym ARIES), Nainital India. This homogeneous set of data have been used to study behavior of optical light/color curve, and to gain insight into objet-to-object peculiarity. We derive integrated luminosities for types IIP, Ibc and luminous SNe. Two peculiar type IIP events having photometric properties similar to normal IIP and spectroscopic properties similar to sub-lumnious IIP have been identified.

Four open questions in massive star evolution

We discuss four questions dealing with massive star evolution. The first one is about the origin of slowly rotating, non-evolved, nitrogen rich stars. We propose that these stars may originate from initially fast rotating stars whose surface has been braked down. The second question is about the evolutionary status of alpha-Cygni variables. According to their pulsation properties, these stars should be post red supergiant stars. However, some stars at least present surface abundances indicating that they should be pre red supergiant stars. How to reconcile these two contradictory requirements? The third one concerns the various supernova types which are the end point of the evolution of stars with initial masses between 18 and 30 Msun, i.e. the most massive stars which go through a red supergiant phase during their lifetime. Do they produce types IIP, IIL, IIn, IIb or Ib supernovae or do they end without producing any SN event? Finally, we shall discuss reasons why so few progenitors of type Ibc supernovae have yet been detected?

THE EARLY UV/OPTICAL EMISSION FROM CORE-COLLAPSE SUPERNOVAE

We derive a simple approximate model describing the early, hours to days, UV/optical (UV/O) supernova emission, which is produced by the expansion of the outer ≲10−2 M☉ part of the shock-heated envelope, and precedes optical emission driven by radioactive decay. Our model includes an approximate description of the time dependence of the opacity (mainly due to recombination), and of the deviation of the emitted spectrum from a blackbody spectrum. We show that the characteristics of the early UV/O emission constrain the radius of the progenitor star, R*, its envelope composition, and the ratio of the ejecta energy to its mass, E/M. For He envelopes, neglecting the effect of recombination may lead to an overestimate of R* by more than an order of magnitude. We also show that the relative extinction at different wavelengths (Aλ − AV) may be inferred from the light curves at these wavelengths, removing the uncertainty in the estimate of R* due to reddening (but not the uncertainty in E/M due to uncertainty in absolute extinction). The early UV/O observations of the types Ib SN 2008D and IIp SNLS−04D2dc are consistent with our model predictions. For SN 2008D, we find R* ≈ 1011 cm, and an indication that the He envelope contains a significant C/O fraction.

Bayesian Single-Epoch Photometric Classification of Supernovae

Ongoing supernova (SN) surveys find hundreds of candidates that require confirmation for their various uses. Traditional classification based on follow- up spectroscopy of all candidates is virtually impossible for these large samples. The use of Type Ia SNe as standard candles is at an evolved stage that requires pure, uncontaminated samples. However, other SN survey applications, such as measuring cosmic SN rates, could benefit froma classification of SNe on a statistical basis, rather than case by case. With this objective in mind, we have developed the SN-ABC, an automatic Bayesian classifying algorithm for supernovae. We rely solely on single- epoch multiband photometry and host-galaxy (photometric) redshift information to sort SN candidates into the two major types, Ia and core-collapse supernovae. We test the SN-ABC performance on published samples of SNe from the Supernova Legacy Survey (SNLS) and GOODS projects that have both broadband photometry and spectroscopic classification (so the true type is known). The SN- ABC correctly classifies up to 97% (85%) of the Type Ia (II-P) SNe in SNLS, and similar fractions of the GOODS SNe, depending on photometric redshift quality. Using simulations with large artificial samples, we find similarly high success fractions for Types Ia and II-P, and reasonable (~75%) success rates in classifying Type Ibc SNe as core-collapse. Type IIn SNe, however, are often misclassified as Type Ia. In deep surveys, SNe Ia are best classified at redshifts z ≳ 0.6 or when near maximum. Core-collapse SNe (other than Type IIn) are best recognized several weeks after maximum, or at z ≾ 0.6. Assuming the SNe are young, as would be the case for rolling surveys, the success fractions improve by a degree dependent on the type and redshift. The fractional contamination of a single-epoch photometrically selected sample of SNe la by core-collapse SNe varies between less than 10% and as much as 30%, depending on the intrinsic fraction and redshift distribution of the core-collapse SNe in a given survey. The SN-ABC also allows the rejection of SN impostors such as active galactic nuclei (AGNs), with half of the AGNs we simulate rejected by the algorithm. Our algorithm also supplies a good measure of the quality of the classification, which is valuable for error estimation.

The fibril structure of type V collagen triple-helical domain

Although the triple-helical structure of fibrillar collagen is regarded in general as being quite similar, each type of collagen molecule has inherent characteristics in the triple-helical domain. Few studies have ever been performed in terms of the aggregate structure of the triple-helical domain of fibrillar collagen. Reconstituted aggregates from the purified triple-helical domain of each type of fibrillar collagen might amplify the subtle differences in the structural characteristics of each type of collagen molecule. In this study, the reconstituted aggregate structure of pepsin-treated type V collagen (type Vp collagen), that is, virtually its triple-helical domain was characterized by transmission electron microscopy. Pepsin-treated type I (type Ip) and type II (type IIp) collagen were compared with type Vp collagen. Unique features of the aggregate structure of the triple-helical domain of the type V collagen can be summarized as follows:1.Type Vp collagen formed fibrils with the D-periodic banding pattern. The banded type Vp fibrils appeared to be of a loosely twisted ribbon-like structure. The average thickness of type Vp collagen fibrils with the banding pattern was significantly smaller than those reconstituted from types Ip and IIp collagen.2.The width of the type Vp collagen fibrils was not affected under the conditions where the D-periodic banded fibrils were formed; the conditions being incubation temperature, protein concentration, and NaCl concentration.3.Type Vp collagen fibrils had little branching and merging. Furthermore, the type Vp collagen fibrils did not bind to each other. On the contrary, type Ip collagen fibrils were often bound to each other and had many branching and merging.These results suggested that the lateral packing of the triple-helical domain of type V collagen is determined by its molecular structure. The characteristics of type Vp collagen fibrils might be explained by their characteristic amino acid composition. A significant feature of the triple-helical domain of type V collagen is the high content of glycosylated hydroxylysine residues. Molecular model building of the collagenous structure suggests that a change in surface roughness is conspicuous by incorporating the glycosylated hydroxylysine residues. More than a ten-fold content of bulky glycosylated hydroxylysine residues in type V collagen compared to that of type I might have a significant influence on both the intermolecular and interfibrillar interactions of the triple-helical domain of type V collagen molecule.

A carbon–oxygen star as progenitor of the type Ic supernova 1994I

SUPERNOVAE are classified observationally as type I (which have no hydrogen emission lines in their optical spectra) or type II (which do have hydrogen lines), and are further subdivided1 into types Ia, Ib, Ic, IIP, IIL and IIb. Type II supernovae are generally thought to result from the explosion of massive stars, and type Ia supernovae from white-dwarf stars that have accreted sufficient mass from a companion to trigger explosion1,2. The origins of types Ib and Ic are much less clear. The Ic class has been particularly controversial, with two main alternatives: the explosion of a massive star that has lost its hydrogen and helium envelopes through fast stellar winds, exposing the carbon- and oxygen-rich core; or the transfer of material to a companion, leaving a small, bare carbon–oxygen (C + O) star which subsequently explodes3,4. We show here that the observed characteristics of SN1994I (in the nearby galaxy NGC5194), which has recently5,6 been classified as type Ic, are best understood on the basis of the second of the two alternatives above: that the progenitor was in a close binary system and lost its outer envelopes, leaving a C + O star (of mass ≈ 2 solar masses) which exploded when its iron core collapsed.

ねり製品の保水性に関する研究 ＩＶ 塩ずりおよび加熱によるすり身の保水性の変化

Changes in the Water Holding Capacity of Surimi Caused by the Addition of Water and Sodium Chloride and by the Subsequent Heat Treatment Yoshiaki Akahane*2 and Yutaka Shimizu*3Changes in the states of water in frozen surimi of Alaska pollack during grinding with water (25%) and Nacl (2.5%), and the subsequent heating (90°C, 120°C), were investigated. The water in surimi was categorized into three types: Ip, IIp and IIIp, by using our press method. Type Ip water, to be regarded as bulk phase water, increased with adding water into thawed surimi, whereas types IIp plus IIIp water, tightly immobilized in protein network, changed little. However, the type Ip water in ground surimi markedly decreased with the addition of NaCl while types IIp plus IIIp water increased, according to the hydration of the proteins. After the salt-ground surimi was heated, type Ip water increased again and types IIp plus IIIp water decreased proportionally. On the other hand, the type Ip water could be classified into two further sub-states, Ip-A and Ip-B, by compressing gel slices under a series of low pressures between 3 and 10kg/cm2. The type Ip-A water was regarded as “free” and Ip-B as “entrapped” in gels. With the passing of heating time, Ip-A water went on increasing and Ip-B did the reverse, although Ip (Ip-A plus Ip-B) water changed little. The increase of Ip-A water was accompanied by the apparent increment of the released water on the cut surface of specimen. The amount of Ip-A from gels highly correlated with “Hardness” as measured by a texturometer.

ねり製品の保水性に関する研究 Ｖ すり身とその加熱ゲルの保水性に及ぼすｐＨと食塩濃度の影響

Water in Alaska pollack surimi and its gel was categorized into types Ip-A (“free water”), Ip-B (loose “entrapped water”), and IIp (tight “entrapped water”) plus IIIp (“immobilized water”) by our press method. The maximal Ip-A and the minimal Ip-B and IIP plus IIIp in amounts were estimated in both non-salt-ground and salt-ground surimi at a pH of about 5; that is, the water holding capacity (WHC) of surimi was minimal at this pH. The amount of Ip-A in salt-ground surimi with pHs below 5 was larger than in the non-salt-ground one. With the increase of pHs above 5, WHC of surimi markedly increased and the amount of Ip-A decreased more in the salt-ground surimi than in the non-salt-ground material. The amount of Ip-A in surimi at pH7, near the ordinary pH value of surimi for kamaboko, reached a minimum after the addi-tion of 2-3% NaCl.After heating surimi with pHs between 5 and 9 at 90°C for 40 min, amounts of Ip-A were also less in salt-ground surimi gels than in non-salt-ground ones. Especially small amounts of Ip-A and large amounts of Ip-B were determined in the salt-ground surimi gel at pH 7, near the ordinary pH value of kamaboko with a high WHC. The salt-ground surimi gel with large amount of Ip-A and the low gel-strength was significantly saltier than that with a small amount of Ip-A and the high gel-strength.

Studies on the water-holding capacity of kamaboko - III. Classification of the existing state of water in kamaboko by expressing, absorbing, and thermogravimetric methods.

The existing state of water in kamaboko was investigated by expressing, absorbing, and thermo-gravimetric methods. Kamaboko specimens were pressed between filter papers at 50kg/cm2. Two break points were found on the curve, which represents the relation between the amount of the expressible water and the expressing time. The result indicates that the existing state of water in kamaboko can be classified into three categories, types Ip, IIp and IIIp. The type Ip water was sque-ezed out rapidly, the type IIp water slowly, and the type IIIp water hardly. Amounts of types Ip, IIp and IIIp water coincided roughly with those of It, IIt and IIIt classified by thermogravimetry. On the other hand, kamaboko specimens sandwiched between absorbing papers were vacuum-packed. One break point was found in the curve, which represents the relation between the amount of the absorbable water and abosorbing time. Water in kamaboko was classified in two states, the type Ia absorbed to the paper easily and the IIa absorbed hardly. The amount of Ia was approxi-mated with that of Ip, and that of IIa with that of IIp plus IIIp. The relative amounts of the Ip, IIp and IIIp on the dry base were measured for the three kinds of kamaboko differing the in amount of added water. The amounts of IIp plus IIIp of all kamaboko tested, were mostly the same. In contrast, the amount of Ip increased markedly with an increase in that of the added water. The type Ip, pro-bably regarded as “bulk phase water”, was thus considered to largely contribute to the texture or wateriness of kamaboko.