Pos(NIC XII)130 And

PoS(NIC XII)130 and

http://pos.sissa.it/ and 250M

110M erg of energy, which can = 52 Ni mass and other observed 56 10 . Since most normal SNe Ic MS

M × Ni mass are reduced compared with 56 Ni production on a sphericity of explosion. In the 56 Ni more than 3.5M 56 Ni. Although the progenitor of SN 2007bi is still unclear, we 56 or so, this is a very exceptional case. The previous study shows that a

1M . 0 ∼ ∗ erg of energy using two massive WO-star progenitors ( 52 of C+O core spherically explodes by core collapse with 3 004). We investigate the dependence of .

0 [email protected] [email protected] [email protected] = Speaker. Recent supernova surveys have foundsupernovae. peculiar type SN Ic 2007bi supernovae,produce is i.e., very reported super-luminous large type as amount Ic oneproduce of of only radioactive the most luminous SNe Ic. It is considered to 40M produce such a large amount of Z spherical case, because large fraction of materialback. is We accreted discuss onto restrictions the on centeral aspherical remnant explosion duequantities models to of fall- from SN 2007bi. Butaspherical in model ﬁnal, of core-collapse considering explosion of such massive restrictions, WO starof we still SN can hold 2007bi. to safely present conclude the progenitor that extend this possibility for the case ofWe aspherical performed (jet-like) a explosion. sequence ofthan 10 hydro-dynamical simulations of aspherical explosion with more case of jet-like explosion both the ejecta mass and produced ∗ Ni production in aspherical explosion of massive Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. c

Hideyuki Umeda Department of Astronomy, School of Science,E-mail: University of Tokyo Takashi Yoshida Department of Astronomy, School of Science,E-mail: University of Tokyo WO star Shinpei Okita Department of Astronomy, School of Science,E-mail: University of Tokyo 56 XII International Symposium on Nuclei inAugust the 5-12, Cosmos, 2012 Cairns, Australia PoS(NIC XII)130 ] ] )

of 1 4 Ni MS ex E 56

Ni if M (2.1) from , 56 O < will be

of C ej ) seems to M M

( Shinpei Okita Ni and elemental Ni) < 7.4M 56 56 hypernova < M( ] constructed CC explosion

5 ]. Proportional constants are 8 erg (called 52 10 , = 2 4 erg can produce more than 3M / / ex 1 3 Ni and light curve evolution of SN 2007bi. ej . Moriya et al. [ 52 E − ej 56

M 4 M 10 / 2 1 / × 2 1 − ex ex 35M 3 ]. We assumed the special case where E E Ni amount will severely depends on the sphericity of 8 ∼ ]. From such extreme production, Gal-Yam et al. [ ∼ ∝ ∝ 3 56 is light curve rising time [ ph . Since SN 2007bi shows no He signature in the spectrum, rise v t

rise 004. They discussed whether the origin of 2007bi is CC or t . from the observational quantities using the relations 0 ex = from the peak magnitude and 3.7M may possibly change the total view of core-collapse scenario for E Ni. From the aspherical model, we will discuss whether CC SN Z

56 of SN 2008D [

]. This is pretty large compared with other luminous SNe Ib/c; 0.6M 1 erg) can reproduce the mass of 51 aspherical effect 10 ] and 0.02M × 2 is photometric velocity and and the metallicity of , 30 of mass. This scenario succeeded mainly in reproducing the yield of

]. v 7

We performed 2D hydro-dynamical simulations in order to model the aspherical explosion. Thus, our aim is to construct an aspherical explosion model based on CC SN with ejecting We considered two WO stars as the progenitors suitable for type Ic SN 2007bi. One is 110M But in general, SN 2007bi cannot be fully explained by CC SN model of spherical explosion, SN 2007bi is reported as one of very luminous type Ic supernovae(SNe). The ejected SN 2007bi is also discussed according to core collapse (CC) scenario. Umeda & Nomoto [ ] investigated the evolution of very massive stars with the main-sequence mass of 100M Ni will be restricted around the axis and fall-back from equatorial region will be considerable. Ni production in aspherical explosion of massive WO star 6 the C+O core of the progenitor is larger than model for SN 2007bi still holds. We determined explosion energy where taken from well known type Ib SN 2008D [ as possible as large amount of SN 2007bi from spherical explosion. 2. Model & Method because such highly energetic explosion more than the nebular spectra [ SN1998bw [ discussed that a SN with a kinetic energy of = (43M < 500M PI SN in terms of theirthan population. that They of concluded PI that SN. the possibility of CC SN is 40 times larger occur aspherically. If the progenitor56 explodes aligned with an axis, spatial distributionWe of can produced easily presume that totalexplosion. ejecta and This in main sequence and the other isthis 250M is preferable property for thiset study. al. More [ details for the progenitors are described in Yoshida They concluded CC SN as[ well as PI SN can be the progenitor of SN 2007bi. Yoshida & Umeda 56 1. Introduction amount is estimated to be 3.5M model of a massive C+O core and synthesized light curves. Spherical explosion of suggested that SN 2007bi is100M originated from Pair instabilitycomposition. (PI) SN of He core progenitor with PoS(NIC XII)130 . , ] ◦ 1

0 SN . op θ Shinpei Okita Ni) < 7.0M 75 and 90 progenitor. . Ni production. 56 shows the pho- from the explo-

56 78 3 , shows the relation rise 5 t . < M( Ni is produced in the K). For jet-like explo- 2.1

67 . We see the total trend 56 progenitor is consistent 9 , op

0 10 . θ ). Figure × 45 2 for the 110M . We assume that SN 2007bi . 5 , 1

5 erg . max > derived from the observation [ , 1 51 ex T 22 − 41M E , 10 50 70 / − ) and approximately maximum explosion 25 ∼ ∼ . , and the 110M and investigate in which range of max WO , op 11 θ M ex , op E θ Ni as a function of 03 . 12000 km s 56

always gives 3 = is 7 and the light curve rising time (summarized in table M ph / 1 op ph max v , θ v − 43.1 60.0 ej Ni is reduced in jet-like explosion. Since the estimated WO progenitor and 28 M 56 M

or so. But as we do not have a clear idea about asphericity of 500 km s ), and WO star mass ( M ◦ / ± MS 250 110 ) because for 250M MS M

M WO M ]. The rising time has large uncertainty because the initial observation is . We took the range of the rising time estimated from the observation as 1 58M . ej ) explosion is likely to lose a large fraction of stellar mass. This is because − ej M op ) and the color shows the ﬁnal destiny of each particle. θ M ◦ . If collapsar engine serving GRB like explosion can be assumed for this hyper- 5 may become 10 . and op 5 days [ θ . op shows the initial distribution of all Lagrangean pariticles for a jet-like explosion 22 ) estimated from eq.2.1. of the progenitors ex shows the mass of ejecta and ejected θ . is equivalent to spherical model. 97 E 1 2 = progenitor is consistent over all the range of ◦ ranges 46 max , ◦ , <

0 Main sequence mass ( ej op ex 30 . rise θ E t M Ni is produced by Si burning in high temperature region ( > rise 90 , t We evaluated the photometric velocity 56 Figure Figure We also calculated nucleosynthesis by post-process. We discretized all the mass element of We modeled aspherical explosion by putting energy into a cone around polar axis with some ph op = < v θ Ni amount for SN 2007bi from some observations seems good to be 3.5M Ni production in aspherical explosion of massive WO star op tometric velocity and the light curve rising time as a function of the opening angle of aspherical The progenitor mass and explosion energy are summarized in table that jet-like (small in sion energy and the ejectaof mass for each aspherical40 explosion model. Eq. sparse. We used the photometric velocity of should be as powerful explosion as possible in order to reproduce extremely large the progenitor into 5200 Lagrangean particles atthermo-dynamical the histories beginning during of the explosion. full All evolution of of them hydro-dynamical follow simulation. the 3. Results model ( narrow region around an axis, and fall-back is distinguished in the equatorial region. and supposed an uncertainty of θ almost maximum ( hypernova, we calculated many models with various 56 Table 1: energy ( opening angle the 250M sion, the high temperature regionthan emerges central only region. around Therefore the56 produced polar axis where contains less density fall-back onto the centralenergy remnant around occurs the heavily. axis,freely. Since material highly nearby aspherical equatorial model plane gives falls kinetic onto the central remnant almost nova model, 2007bi can be reproduced. Our selection of PoS(NIC XII)130 , Z 3 cm) 9 ] ] 10 1 3 × ) and light 0 . ph v 6 Shinpei Okita = Z = ref. R Ni 56 . In either case, the restric- ◦ Others Fall-back 45 is non-negligibly reduced from & ej ), photometric velocity ( op M 6.0 ex θ E 40 Gal-Yam et al. (2009) [ [day] 19 Mazzali et al. (2008) [ > rise 5.0 t ] 1 Ni mass does not become a severe restriction in 4.0 − 56 4 cm] 9 [km s progenitor reproduce all the observational quantities in 12000 10000 3.0 , and ), explosion energy ( ph

ej R [10 v rise t M in which SN 2007bi is reproduced from these simulations. progenitor reproduce in 2.0 op

and θ erg progenitor. Aspherical explosion is driven by energy injection around ph 51 v

. However, as we can see in some of the jet-like models in Figure - 1.0 6 ex 10 / E ex E 0.0

4.0 3.0 2.0 1.0 0.0 6.0 5.0

cm]

Z [10 Z ) of SN 2007bi and well known type Ic SNe SN 2008D. 9 M . model of 110M rise / t 3 ◦ Ni and green particles are other of the two. ej 5 . 56 M ), because very luminous SN 2007bi requires as large explosion energy as possible and 22 are no longer consistent with observation, because is mainly caused by = Initial distribution of Lagrangean particles focused on the central region ( . The models of the 110M always gives large WO op ◦ rise Observed quantities, ejecta mass ( t θ op ej M θ 30 SN M . ∼ Concerning CC explosion model, this study suggests that aspherical explosions as well as We set explosion energy under the assumption that ejecta mass becomes as large as possible We can estimate the range of 2008D 7 2007bi - & and ej WO Ni production in aspherical explosion of massive WO star op ph M tion on spherical one can explain luminous type Ic SN 2007bi. We clariﬁed that jet-like explosion have for the 4. Conclusion θ ( model. The ranges of thedrawn in photometric Figure velocity and the rising time from the observations are also Table 2: large v M this study. Figure 1: 56 axis. Colors show the ﬁnal destinyare of enriched each particle; in Black particles fall into the central remnant, red particles curve rising time ( Aspherical explosion models of the 250M PoS(NIC XII)130 90 ) models ] op ° erg erg models. The θ Shinpei Okita 60 M [M ] 51 51

ej sol op 10 10 θ × × ejects sufﬁciently ,70 ,50 40 30 70 60 50 ex sol sol E 90 30 Opening Angle [ 250M 110M 0

is no longer consistent with explosion 50 45 40 35 30

rise [days] t ej ] 60 ° M 5 90 by observed quantities. This means that energetic explo- ej ej Opening Angle [ ej ] Ni) Ni) ° 30 M , M , M 56 56 erg erg 60 sol sol 51 51 , M( , M( 10 10 with × × sol sol ex 250M 110M ,70 ,50 E Ni mass ejected from aspherical SN explosion with different sol sol 56 30 250M 110M Opening Angle [ of SN 2007bi estimated from observation is drawn by black dashed line. 250M 110M ) Ni 0 connects 56 ( 5 4 3 6 7

Ni and ejecta mass is reduced by fall-back.

sol 2.1 ] [M Ni) M( M 56 56 Ejecta mass and The photospheric velocity (left panel) and the light curve rising time (right panel) as a function of . Eq.

12000 11000 15000 14000 13000

[km s [km v

] M -1 The most severe restriction is emerged from whether limited amount of Ni production in aspherical explosion of massive WO star Figure 2: 56 lower limit for large sion requires sufﬁciently large ejecta mass. Some of extremely jet-like (the most small more severe restriction to reproduce SNreason 2007bi is that than simple spherical explosion model. The main Figure 3: the opening angle. In theuncertainty. left In panel, the solid right line panel, is dotted the line observed is velocity the and lower the limit two of dashed the lines observed indicate light the curve rising time. cannot eject sufﬁciently much material, becausetorial they plane cannot falling prevent the onto material the nearby central the remnant. equa- Reduced PoS(NIC XII)130 . , star

, , and for ◦ 45 , in Shinpei Okita & op (2009) 624. θ 462 (2011) L83. Science 717 , PoS (NIC XII 2012) 062 , ApJ , models the range is

(2008) 1185. 6 (2008) 1014. 321 673 Ni can be Produced in Core-Collapse Supernovae? Evolution 56 ApJ Science , , Evolution of Very Massive Stars and Type Ic Supernova . Stars ◦

30 . We consider such a progenitor is appropriate to become hypernova ◦ How Much A Progenitor for the Extremely Luminous Type Ic Supernova 2007bi & op (2009) 376 θ The Nebular Spectra of the Hypernova SN 1998bw and Evidence for Asymmetry The Metamorphosis of Supernova SN 2008D/XRF 080109: A Link Between Supernova 2007bi as a Pair-Instability Explosion A Core-Collapse Supernova Model for the Extremely Luminous Type Ic Supernova 138 SN 2008ha: An Extremely Low Luminosity and Exceptionally Low Energy XII International Symposium on Nuclei in Cosmos (2001) L78. ApJ , (2001) 1047. 412 models it is

559 T. Yoshida & H. Umeda, T. Yoshida, S. Okita, H. Umeda, J.F. Foley et al., Supernova T. Moriya et al., A. Gal-Yam et al., P.A. Mazzali et al., ApJ P.A. Mazzali et al., Supernovae and GRBs/Hypernovae H. Umeda & K. Nomoto, and Explosions of 30-100 M 2007bi: An Alternative to the Pair-Instability Supernova Model MNRAS proceedings of Although it has not been well known how jet-like explosion occurs in hypernova progenitor, Ni production in aspherical explosion of massive WO star [8] [6] [7] [3] [4] [5] [1] [2] the 250M 56 energy and observed quantities. Therefore, ourcalculation aspherical is models consistent clarify the with range observation. in which For model the 110M the scenario that the SN 2007bi is originated from CC SN still holds. Supposing that 250M at the end of itsmay life become broader explodes than like 30 GRBand but serve fails the to explosion like collimate SN the 2007bi. jet, opening angle ofReferences explosion