PoS(NIC XIII)150
advertisement
Observations of the extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck, Austria and Dr. Karl Remeis–Observatory & ECAP, Astronomical Institute, Friedrich-Alexander University Erlangen-Nuremberg, Sternwartstr. 7, D-96049 Bamberg, Germany E-mail: veronika.schaffenroth@uibk.ac.at Norbert Przybilla Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck, Austria Keith Butler Munich Observatory, Ludwig-Maximilians University, Scheinerstr. 1, D-86179 Munich, Germany Andreas Irrgang, Ulrich Heber Dr. Karl Remeis–Observatory & ECAP, Astronomical Institute, Friedrich-Alexander University Erlangen-Nuremberg, Sternwartstr. 7, D-96049 Bamberg, Germany Some young, massive stars can be found in the Galactic halo. As star formation is unlikely to occur in the halo, they must have been formed in the disk and been ejected shortly afterwards. One explanation is a supernova in a tight binary system. The companion is ejected and becomes a runaway star. HD 271791 is the kinematically most extreme runaway star known (Galactic restframe velocity 725 ± 195 km s−1, which is even larger than the Galactic escape velocity). Moreover, an analysis of the optical spectrum showed an enhancement of the α -process elements. This indicates the capture of supernova ejecta, and therefore an origin in a core-collapse supernova. As such high space velocities are not reached by the runaway stars in classical binary supernova ejection scenarios, a very massive but compact primary, probably of Wolf-Rayet type is required. HD 271791 is therefore a perfect candidate for studying nucleosynthesis in a supernova of probably type Ibc. The goal of this project is to determine the abundances of a large number of elements from the α -process, the iron group, and heavier elements by a quantitative analysis of the optical and UV spectral range. Detailed line-formation calculations are employed that account for deviations from local thermodynamic equilibrium (non-LTE). We intend to verify whether corecollapse supernova are a site of r-process element production. Here, we state the current status of the project. XIII Nuclei in the Cosmos, 7-11 July, 2014 Debrecen, Hungary ∗ Speaker. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ PoS(NIC XIII)150 Veronika Schaffenroth∗ The extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova Veronika Schaffenroth 1. Runaway stars Figure 1: Regions of origin for HD 271791 in the Galactic plane calculated by varying the proper-motion components within their measurement errors. The position of HD 271791 projected to the Galactic plane is marked. The red area is derived from our proper-motion measurement, whereas the blue area follows if proper motions from the UCAC2 catalog are used. From [5]. Such stars are therefore ideal candidates for studying nucleosynthesis in core-collapse SN. They may in particular facilitate to decide whether core-collapse SN are sites of r-process nucleosynthesis, or not. HD 271791 is the kinematically most extreme runaway star known (with a Galactic restframe velocity 725 ± 195 km s−1 , larger than the Galactic escape velocity). Such velocities were believed only to be reached if a star is ejected by interaction with the Galactic supermassive black hole [4]. However, HD 271791 is much younger than the flight-time from the centre of the Galaxy to its current position. Moreover, a reconstruction of the orbit shows that HD 271791 originates in the outskirts of the Galaxy (see Fig. 1). This rules out the supermassive black hole scenario. An abundance study can be used to investigate the viability of the SN scenario. 2. Observations We intend to perform an abundance study of HD 271791 (B2-3 III, V = 12.26) in the optical and the UV spectral range in order to verify the contamination of the stellar atmosphere with SN ejecta. To this aim, we obtained high-S/N optical ESO-VLT UVES spectra in the 3000 to 10 000 Å range at resolving power R =λ /∆λ = 30 000. At UV wavelengths we obtained HST/COS spectra in the 1150 to 1800 Å range at R = 16 000-21 000 and HST/STIS data in the 1600 to 3100 Å region at R = 30 000. These allow us to improve on and vastly extend our initial investigation of the star [6]. 2 PoS(NIC XIII)150 Young, massive stars are usually found close to the Galactic plane, typically in open clusters and associations. Some of them, however, are observed at high Galactic latitudes far away from star-forming regions. Since no gas clouds are known in the halo that have a sufficiently high density to form massive stars, these stars must have formed in the Galactic disc, and afterwards migrated outwards (’halo run-away OB stars’). They are thought to have been ejected from their place of birth and accelerated to high velocity by dynamical processes either during the initial dynamical relaxation of a star cluster [1], or in binary interactions inside star clusters [2], or by means of a binary supernova (SN) explosion [3]. In the latter scenario the surviving companion is ejected with roughly the orbital velocity and becomes a runaway star. To distinguish the SN scenario from the other scenarios an abundance study may be employed, as the atmosphere of the close companion – afterwards the runaway star – is polluted by the SN ejecta. An enrichment of the elements existing in the SN ejecta is expected. The extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova Veronika Schaffenroth ✶ ✷ ✝ ❍➪ õóôõ ✞②❞r♦❣✟♥ ✹óôô ✂❡❧✄☎✆ ✸ ❩ ö ÷ø ❙②✳❜✴✸ òóôõ ùúûüýýþÿ♠ ✩✪✫✬✭✮ ❏❏ ì ✞✟✠✡☛☞✌☞ ✞✟ ✍✎✏ ▲➊ ✻óò✹ ✐t❤✐✉✁ ✁✂✄☎✆✝✆ ä ❏✼ Û Ò ➬ ➽➾ í å ➧ Ó ➮ ➻➸➺➼➻ îïðïñ ➻➵➺➸➻ æçèéêë ➻Ú➺➸➻ ÜÝÞßàáâã ➻Ñ➺➸➸ ÔÕÖ×ØÙ ➻➷➺➸➸ ➱✃❐❒❮❰ÏÐ ✁ ◆▲❚❊ ♥♦t ✐♥❝❧✉❞❡❞ ✐♥ t❤❡ ♠♦❞❡❧ ❲✰✭✱✲✪ ✹✻✿❀✿❁❂ ❃❄❀✿ ❏➒ ❏➈ ❷❿ ❷❸ ❏✈ ➚➪ ➵➸➺➻➼ ➶➹➘➴ ❏❭ ➧➨ ➛➜ ➓① ➉➊ ➀ ❹ ✇① ❪❫ ⑩⑩✻●● ➩➫➭➯➲➳ ⑩✹✻❊❍ ➝➞➟➠➡➢➤➥➦ ⑩➑✻●✽ ➔→➣↔↕➙➣↔ ⑩✽✻✺● ➋➌➍➌➎➏➐ ❊✺✻●❶ ➁➂➃➄➅➂➃➆➇➄ ❊⑩✻✺❶ ❺❻❼❽❻❾ ❊❬✻✹❬ ②③④⑤⑥⑦⑧⑨ ❊●✻●❬ ❴❵❢❥q ❏❑ ✼✿ ï➎ ïï ï✆ ✑❉ ❀❁ ❙✰ ✹✺✻✺✽ ❂❃❄❅❆❇❉ ❿❿❾❼➯ ❿➭❾➢➭ ❽✃❾❼❿ ❽➌❾✃✃ ✱✲✳✴✵✶✷✸ ✩✪✫✬✭✪✮✯ ✢✣✤✣❞✥✦✧ ✗❤✘✙✚✛✜✚ ✆➪ ✆✲ ❚★ ✑✏ ▲ ❊●✻❍✺ P❖◗❘❯❯❲❳❨ ✆✩ ✹✤ ❱ ✹➎ ❈Õ ❉✑ ï▼ ï➪ ✑✾ ï✲ ✆✤ ✆➎ ✆ï ⑤⑤ ⑤❉ ✆✺ ✆▼ ▼✒ ❋✍ ✠✡ ◆☎ ❈✂ ❩♥ úû ðñ æç ❽❿❾❼❿ ❽❽❾➢❽ ❽➢❾❼➱ ❽➢❾➯❼ ➯➱❾❽❽ ➯❽❾➱❼ ➯❼❾➭➌ ➭➌❾➯➍ ➭❿❾❼➌ ➭➢❾❼➯ ➭❼❾❼✃ ➢➱❾➢✃ ■✎✏✑ ☛☞❜❛✌t ✆✝✞❦✟❧ üýþþÿ✉♠ òóôõö÷øùõ èéêëìíî ßàáàâãäå Ö×ØÙÚÛÜ ❮❰ÏÐÑÒÓ ✓✔✕❣✔✕✖s✖ ❉⑤ ✹✹ ✹✺ ✹▼ ✄♦♣♣❡r ❉❊ ✐✁❝ ✹✲ ✹✩ ✺✤ ✏✙ ÝÞ ✏✑ ÔÕ ✺✆ ✺✹ ■➶ ➲➳ ➤ ↔↕ ➏➐ ➀➁ ⑥⑦ ■❵ ■❤ ➁◆ ❋➓ Ú✴ ✪✫ ❙Û ❙❜ ❚✒ ■ ➢❽❾❿➭ ➢➭❾➯➌ ➢➢❾❼➍ ❼➍❾➌➌ ❼➌❾❼➍ ❼❽❾❼❿ ✇①③④ ✶✵✶✳✵✣ ✶✵✁✳✾✶ ✶✵✻✳★✁ ☛✎✼✌❅✼ ✶✶✁✳★✶ ✶✶★✳✽✁ ✶✶✽✳✣✶ ☛☞☛✌✼✍ ☛☞✼✌✍✎ ✶✁✻✳✾✵ ➹➘➴➷➬➷➘➮ ❚❚ ➵➸➺➻➼➸➽➾➚ ➥➦➦➧➨➩➫ ❚● ✲✿ ÿ❛ Üþëßþþ ✺✼✧✼★ ✦ ❇ r✐✉♠ ❋❀ ❅❇❇➢❋ ❁❂❃❄❅❆❈❊ ö÷ Üëìßàë øùúûúüùý ➑✵Ï ✲✲ ✳✴ ❅❇❇❰❋ ✶✷✸✺✻✾ ✽✾④✶✵✷ ✥✥ ✒ ➤❿ ❺❻ ❹✑ ❼❽❾❿➀❽❾➁➂ ❿⑧ ✯✯ ❆✑✒✓✔✕✓✖s íî ÜëÝßìà ïðñòóôõ ▲✩ ❘❢ ❅❇❰❇❋ ❅❇❰❾❋ ✪✫✇✬✭✮❝✯✰✱ ✚✛✜✢✣✤✥✦✤❞✧✛★ ÝÜ Þ Ý ➑➒➓➔➒→➣ ✿â ➑✵✹ ➤ ✗ ✘❛✙✚✛❛✙✜✢✣✤ ➙➛➜➝➞➟➛➠➡ ✿➀ ➈ã ÜÝÞßàá äåæçåèéê ➯ ●❍ ❉✓ ❅❇❰❇❋ ✔✕✖✗✘✕✙ ❷❸☞✍✎✏ ⑧î Ô ÏÐÑÒÐÓ ÕÖ×ØÙÚÛ× ➠ ●❍ ❙❣ ❅❇❰❰❋ ✡☛☞❜✌✍✎✏✑✒ ➷➬ ✶Ï✻Ð❮✶ ➮➱✃❐❒❮❰ ✼ ●❍ ➍Ò ❝❢❣❥❦♣q❢s ✿● ➾ò Ý✑ßÞÛÜ ➚➪➶➹➘➶ ➑✵✽ ❍ò ❅❇❰❉❋ ❛ss✁✂✄ ❇❤ ❅❇❰➌❋ ☎♦✆✝✞✟✠ ✄▲ ❥❦ ❩❬ ✑ ✶✹✹Ð❮✹ q✈✇①③④⑤⑥⑦⑧⑨⑦ ❭❪❫❴❵❝❢❣❝ ÝàßÞ Ý ⑧á ⑧⑨⑩❶❷⑨❸❹❺❻ ➛➴ ✄✵ ➤⑧ ⑩❶ ÝàßÞÝÛ ➂➃➄➅➆➇➈➉➊➋ ➛❧ P☎ ❅❾➌❈❋ ▼◆❖◗❘❯❱❲❳◗ ➍➶ ❅ ➙ ❙❆ ✺ ✠ ❇❈❋❈■❏❑❋ Ý ßÞÜ ⑧➲ ❨❩❬❭❪❫❴ ✿✿ ➳❀ Ý✑ÛÞÛÛ ➵➸➺➻➺➼➽ ü ●❍ P❖◗◗❖❘❯❱❲ ✿✲ ➤➥ Ý✑✺Þß❹ ➦➧➨➩➫➭➯➲ ●●❍ ●❍❏✈❑▲ ➛➜ ➝➞ ✶✾✻Ð✾✼ ➟➠➡➢ ●●● ✿❀❁❂❃❄❂ ✲➑ ✬✭✮✯✰✱ ✲➇ ➒➓ ÛßßÞ✺✑ ➔→➣↔↕➣➙ ➑➑Ù ➈➉ ❹ ➊➋➌➍➍➎➏➐ ÛßàÞÜ ➑➑Ï æç ýþ ñò ÚÛ ➓➔Ð ❅❇❰❨❋ ❅❇♣❾❋ ❅❇♣❇❋ ❅❇❨➢❋ ➏❇❨❰➐ ÿ❡✐t♥❡r✐✉♠ óôõö÷øôùøúûö èéêëìíêëîïð ÜÝÞßàáâãâäå ÑÒÓÒÔÕÖÔ×ÓØ ✸ ➙ ✷➵ ✺ ✑✠ ✽✿❀❁❂❃✿❄ Ý ÝÞ ⑧➤ ➙➲ ●❞ ✺✡ÞÛ✺ ✮❛✯✰✱✲♥✲✳✴ Ý ⑧➙ ✄✥ ï✦ ✶✤ÏÐ✾❰ ✧★✩✪✫✬✭ ➍➎ ✒ ➙➙ ➙ ❉② ✠ ✺ ✘✙s♣✚✛s✜✢✣ Ý ÛÞ ß ⑧❿ ✥✦✧ ✲➀ ➁➂ ❼❽❾❿❼ ➃➄➅➆ ●● ➶ ➹➘ ❅❇❨♣❋ ➴➷➬➮➱✃❐❒❮ ➙❿ ❍❑ ✠ ✑ ✓♦✔✕✖✗✕ Ý àÞ Ü ⑧⑧ ❆✚t✛✜✢✚② ❦⑦ ⑨☛ ✠✡ÞÛ✠ ❊☞✌✍✎✏ Ý ●❍❍ ✓✔❧❧✕✖✗✕✘ ❦❧ ⑧⑨ ❮ÑÏÐ✾Ï ⑩❶❷❸❹❺❻ ●● ➯ ♣q ❪❫❴❵❥ ✈①②①③④⑤⑥ ●● ➠ ✄➍ ❚☎ ✶✻ÏÐ✾❰ ✆❤✝❧✞✝✟ ➑➑➒ ✄☎♥♦♥ ■❏ ❅❇❇❇❋ ❑▼◆❖P ●● ➃ ●❍● ✵ ➎ ❨❜ ✶✼❰ÐÑ✹ tt❡r✁✐✉✂ ●❍■ ïð âã Ó ➹➘ ➳➵ ➥➜ ➛➜ ➏➐ ➀➁ ⑨⑩ qr ❬❭ ❅❇❇♣❋ ÛÜÛÞßà ÛÜÝÞßà ❮❰ÏÐÑ❰ ❅❇➢♣❋ ❅❇➌➌❋ ❅❇➌➢❋ ❅❇➌♣❋ ❅❇➌♣❋ ❅❇❈❾❋ ❅❇❈❇❋ ❅❇❈♣❋ ❅❇❈❨❋ ❅❇❈❉❋ ñòóôõö÷ äåæçèéçêëêìí ÔÕÖ×ØÙÚ ➴➷➬➮➱✃❐➱❒ ➸➺➻➼➽➾➚➻➪ ➦➧➨➩➫➭➫➯➧ ➝➞➟➠➞➡ ➑➒➓➔➒→➣↔↕ ➂➃➄➅➆➇➈➉➅➊➋ ❶❷❸❹❺❻❷❸❷❼❽ ✇①③⑤⑥⑦⑤ ❪❫❴❵❫❢❫✈❣❥❦ ▼❖P◗❘❯❱❳ ♠ ❯Ð ❅❇❾◗❋ ❱❲❳❨❳❩❬❭ ❳✂ ✶✸✶✳✁✾ ✲● ➲➳➵ ➡➢ ➓➔→ ➄➅➆ ➏❇❨❨➐ ❅❇❨❉❋ ➏❇❉➌➐ ❅❇❉➢❋ ➸➺➻➺➼➽➺➾➚➻➪ ➤➥➦➧➨➩➫➨➥➭➩ ➣↔↕↔➙➛➜➝➞↕➟ ➇➈➉➈➊➋➌➍➉➎ øù úûüýþýÿ ✝✞❞✟✠✡ ✲❚ ❏❑ Figure 2: Periodic table showing all elements implemented in our spectrum synthesis. The elements marked in red can be accounted for in non-LTE, the ones marked in green only in LTE. 3. Methods & Analysis Techniques In a first step, the atmospheric parameters of the star and abundances for a restricted set of elements were determined by non-LTE modelling of the entire optical spectrum [7, 8, 9]. In brief, this is based on a hybrid non-LTE approach, which allows even highly complex model atoms to be employed. Model atmospheres were calculated under the assumption of LTE with the ATLAS 12 code. The coupled radiative transfer and statistical equilibrium equations were solved using D E TAIL, providing non-LTE level populations. Synthetic spectra were then computed with S URFACE. The spectrum synthesis for the UV wavelength range had to be implemented in the course of our project. Lists of spectral lines were adopted for all desired elements, using essentially all available atomic data from the literature. Main data sources were NIST1 , the Kurucz database2 , the Iron Project, e.g. [10], and the Morton compilation [11]. Figure 2 shows, the elements currently available for spectrum synthesis. The limiting factor of this project is missing atomic data. For many atoms only data for neutral or single-ionized atoms were available, whereas data for multipleionized atoms are required because of the high effective temperature of HD 271791. As the lines of the runaway star are very broad due to the high rotational velocity, they were not suitable to test the synthetic spectra. Therefore, we used bright B-stars with similar parameters and slow rotation (ι Her, γ Peg, HR 1840) for this purpose. Based on atmospheric parameter and abundances (including iron) determined from the optical spectra – which allows a considerable part of the UV line forest to be treated as background lines – elemental abundances for other iron group and heavier elements were derived by fitting synthetic spectra to observation. The abundance determination was performed strictly differentially in order to minimise systematic errors. Such an approach is particularly suited to the identification of abundance peculiarities. 1 http://www.nist.gov/pml/data/asd.cfm 2 http://kurucz.harvard.edu/ 3 PoS(NIC XIII)150 Ú→ Üþ✷ßàÜ ❈❛❡s✁✂✄ ✿➇ ❐❒ The extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova Veronika Schaffenroth 0 -0.05 -0.1 [X/H] -0.15 -0.2 -0.25 -0.3 -0.4 C N O Ne Mg Al Element Si S Fe Figure 3: Abundances of HD 271791 as determined from the optical spectrum. The left panel shows the abundances relative to a representative B-star sample (Irrgang et al. in prep.). The baseline metallicity of HD 271791 relative to solar values [12], [Fe/H], is marked by the solid line. The right panel shows the abundances (normalised to iron) compared to hypernova/supernova (HN/SN) yields of Nomoto et al. [13]. 4. Results Optical analysis. Atmospheric parameters of HD 271791 as derived from the analysis of the optical spectrum are summarised in Table 1. A comparison of elemental abundances in the star to those from a representative sample of 63 nearby B-stars by Irrgang et al. (in prep.) are shown in Fig. 3. As it is not expected that the core-collapse SN ejecta that polluted the atmosphere of the runaway contained much iron, we use iron as a baseline. The iron abundance in HD 271791 is ∼0.3 dex lower than in the comparison sample. This is not surprising, as the star originates from the metal-poor outskirts of the Galaxy. On the other hand, several of the α -elements, e.g. Ne, Mg, Si and S, are enhanced compared to abundance values expected for the metallicity of HD 271791. The right panel of Fig. 3 shows a comparison of the elemental abundances (normalised to iron) with hypernova/supernova yields of Nomoto et al. [13]. A qualitative agreement between theory and observation is reached for both the hypernova and the supernova yields. Only the oxygen abundance is smaller than would be expected by theory. However, that may be explained because of the use of integrated yields. Chemical homogeneity is not expected within SN ejecta. Therefore, detailed simulations of the SN explosion and of the accretion of the SN ejecta on the runaway are required to improve on the quantitative understanding. In any case, the observed enrichment in the α -elements indicates an ejection of HD 271791 by a SN explosion in a very tight system. To explain the extreme velocity a very massive but compact primary, probably of Wolf-Rayet type is required. Table 1: Atmospheric parameters of HD 271791 as derived from the optical UVES spectrum Parameter Teff log g ξ Value 18700 ± 50 3.15 ± 0.02 5.9 ± 0.1 Unit K cgs km s−1 Parameter v sin i ζ vrad 4 Value 128 ± 1 22 ± 4 443 ± 1 Unit km s−1 km s−1 km s−1 PoS(NIC XIII)150 -0.35 The extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova Veronika Schaffenroth ι Her τ Sco HR1861 0.6 0.4 [X/H] 0.2 0 -0.4 -0.6 C N O Al Si Ti V Cr Mn Fe Co Ni Cu Zn Figure 4: Abundances for three comparison stars of different Teff , determined from the UV spectrum relative to solar values. The error ranges correspond to the standard deviation from the individual line analysis. UV analysis. Because of the complications caused by the high rotational velocity of HD 271791 on the UV spectral analysis, no results are currently available on this. However, the tests of the models and analysis methodology on the three slowly-rotating comparison stars were highly successful. Abundances of several elements from the UV analysis, derived from single unblended lines, are shown in Fig. 4. They are displayed relative to the abundances from the optical analysis (C, N, O, Al, Si, Fe) or relative to solar values for the remaining elements. The UV analysis reproduces the results from the optical within the errors for all three stars. Moreover, abundances for the other iron group elements turn out to be close to solar, recovering a trend that is found for most of the previously determined B-star elemental abundances. Figure 5 shows a comparison of a synthetic spectrum calculated based on abundances determined from the optical analysis or for solar abundances with an HST/STIS spectrum of ι Her. While there are still some lines missing, the overall match is highly encouraging. We are confident that our spectrum synthesis in the UV has reached a similar degree of maturity as in the optical [8] and provides reliable abundances. 5. Outlook In the next step we intend to derive abundances of the heavier elements from blended lines. This will lay the grounds for determining abundances for the rapidly rotating HD 271791 and for comparing those with abundances of standard stars. This is in order to constrain iron group and heavier element nucleosynthesis in the particular SN event that ejected HD 271791. In the future we want to construct non-LTE model atoms for the iron group elements to minimise remaining systematic error sources. HST spectroscopy of additional runaway stars would be interesting to study nucleosynthesis in core-collapse SNe more comprehensively. Acknowledgements. VS acknowledges funding by the Deutsches Zentrum für Luft- und Raumfahrt (grant 50 OR 1110) and by the Erika-Giehrl-Stiftung. 5 PoS(NIC XIII)150 -0.2 MC CTno II Noi I I CFSeiiIIIIIIII o II III Fe I II C Co I I o N IIII Ci MNo III ni IIII MF IIIII en I FFe IIIII e III III TFei II Ti I NI i I MC IIII nu III I N i FFee II FFe III e III Fe IIIIII I FFNe II ei N III iI II F Ce I M o II n III M III FFen II Fee IIIII IIII I Veronika Schaffenroth A Al I N Nil IIII FFei IIII e II MFe IIII nI FFe IIIII C e III o I MFFFe IIII en FFe IIIIIIIII FNeee IIIII C iIIIIIIII o II I Fe II I Fe II I C Fo I Ce IIII o I II TFie I IIII I Fe I FFe II e III II Fe II I C Feo I MN I II ni III IIII I Fe Fe III M nII II TFei I FFeeIII III Fe II F I Me IIII Fen I II FFe III Ce III Fe IIIII F I FFee III e III C IIII o Fe II FFe IIII Fe I FFCee IIIIII CFe IIIIIII Ceo I FFo II CFee IIIIIII FFeeo IIIIII e IIIII F IIII Fe TFeei III F IIII Ce I I oI Fe IIII I Fe II I CFFNeei II o II III I FCe A III F l II Fee III M FFenIIII e IIIII Fe II III I Fe Fe III M nII M III Nn I iI I II Fe Fe III II M I Fen I II N III iI II 9.5×10-10 Fe F I FFeee IIII FFee IIIII II Fe IIIII I FFe II e Fe IIIII Fe III FNeiII Fe IIIII M nIIII I F I Ce II o I Fe III F II Me I I n II II M Fen I Fe I II IIII I Fe N II i I Fe III M FFeenIII III III Fe II I Fe Fe III II I FFe M enIII NC III FNeii IIII II FNe II i III I CC I II oI II I Fe II I The extreme runaway HD 271791: nucleosynthesis in a core-collapse supernova 9×10-10 8.5×10-10 8×10-10 7.5×10-10 Flux [erg s−1 cm−2 Å−1 ] 7×10-10 6.5×10-10 6×10-10 5.5×10-10 5×10-10 4.5×10-10 4×10-10 3.5×10-10 3×10-10 2.5×10-10 2×10-10 1.5×10-10 4 0 -4 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 λ [Å] 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 Figure 5: Comparison of the observed UV spectrum of ι Her (HST/STIS) with a synthetic spectrum based on abundances determined from the optical analysis, if available, and solar abundances for the rest of the elements. The lower panel shows the residuals. References [1] A. Poveda, J. Ruiz, & C. Allen, Run-away Stars as the Result of the Gravitational Collapse of Proto-stellar Clusters, Boletín de los Observatorios Tonantzintla y Tacubaya 4 (1967) 86 [2] P.J.T. Leonard, & M.J. Duncan, Runaway stars from young star clusters containing initial binaries. I Equal-mass, equal-energy binaries, AJ 96 (1988) 222 [3] A. Blaauw, On the origin of the O- and B-type stars with high velocities (the “run-away” stars), and some related problems, Bull. Astron. Inst. Netherlands 15 (1961) 265 [4] J.G. Hills, Hyper-velocity and tidal stars from binaries disrupted by a massive Galactic black hole, Nature 331 (1988) 687 [5] U. Heber, et al., The B-type giant HD 271791 in the Galactic halo. Linking run-away stars to hyper-velocity stars, A&A 483 (2008) L21 [6] N. Przybilla, et al., HD 271791: An Extreme Supernova Runaway B Star Escaping from the Galaxy, ApJ 684 (2008) L103 [7] M.F. Nieva, & N. Przybilla, Hydrogen and helium line formation in OB dwarfs and giants. A hybrid non-LTE approach, A&A 467 (2007) 295 [8] M.F. Nieva, & N. Przybilla, Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models, A&A 539 (2012) A143 [9] A. Irrgang, et al., A new method for an objective, χ 2 -based spectroscopic analysis of early-type stars. First results from its application to single and binary B- and late O-type stars, A&A 565 (2014) A63 [10] A.K. Pradhan, The Iron Project, in proceedings of Atomic Data Needs for X-ray Astronomy (2000) 69 [11] D.C. Morton, Atomic Data for Resonance Absorption Lines. II. Wavelengths Longward of the Lyman Limit for Heavy Elements, ApJS 130 (2000) 403 [12] M. Asplund, et al., The Chemical Composition of the Sun, ARA&A 47 (2009) 481 [13] K.Nomoto, et al., Nucleosynthesis yields of core-collapse supernovae and hypernovae, and galactic chemical evolution, Nucl. Phys. A 777 (2006) 424 6 PoS(NIC XIII)150 χ 2 -2
