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Laboratory evidence for the formation of hydrogenated fullerene molecules. 氢化富勒烯分子形成的实验室证据。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2019-04-01 Epub Date: 2020-10-12 DOI: 10.1017/S1743921319007567
J D Thrower, G Pantazidis, M Scheffler, F D S Simonsen, P A Jensen, L Hornekær
{"title":"Laboratory evidence for the formation of hydrogenated fullerene molecules.","authors":"J D Thrower, G Pantazidis, M Scheffler, F D S Simonsen, P A Jensen, L Hornekær","doi":"10.1017/S1743921319007567","DOIUrl":"10.1017/S1743921319007567","url":null,"abstract":"<p><p>Experimental evidence for the formation of hydrogenated fullerene molecules is presented. Films of C<sub>60</sub> were grown on a highly oriented pyrolytic graphite (substrate) and exposed to a beam of deuterium atoms. Thermal desorption combined with mass spectrometry was used to determine the deuterated fullerene products formed, revealing a maximum degree of deuteration corresponding to C<sub>60</sub>D<sub>36</sub>. Release of D<sub>2</sub> from the deuterated C<sub>60</sub> film occurs at a much higher temperature than for D-saturated graphite.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"15 Suppl 350","pages":"144-147"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1743921319007567","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38604833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Sun: Our own backyard plasma laboratory. 《太阳报》:我们自家后院的等离子实验室。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2019-04-01 Epub Date: 2020-10-12 DOI: 10.1017/s1743921319008366
Peter R Young
{"title":"The Sun: Our own backyard plasma laboratory.","authors":"Peter R Young","doi":"10.1017/s1743921319008366","DOIUrl":"https://doi.org/10.1017/s1743921319008366","url":null,"abstract":"<p><p>The Sun's atmosphere increases in temperature from 6000 degrees at the surface to over a million degrees at heights of a few thousand kilometers. This surprising temperature increase is still an active area of scientific study, but is generally thought to be driven by the dynamics of the Sun's magnetic field. The combination of a 2-to-3 order of magnitude temperature range and a low plasma density makes the solar atmosphere perhaps the best natural laboratory for the study of ionized atoms. Atomic transitions at ultraviolet (UV) and X-ray wavelength regions generally show no optical depth effects, and the lines are not subject to the interstellar absorption that affects astronomical sources. Here I highlight the importance of atomic data to modeling UV and X-ray solar spectra, with a particular focus on the CHIANTI atomic database. Atomic data needs and problems are discussed and future solar mission concepts presented.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"15 Suppl 350","pages":"333-340"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/s1743921319008366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38352125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
H2 catalysis through superhydrogenation of interstellar polycyclic aromatic hydrocarbons. 星际多环芳烃超加氢催化H2的研究。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2019-04-01 Epub Date: 2020-10-12 DOI: 10.1017/S1743921320000034
Frederik Doktor S Simonsen, Pernille A Jensen, Anders W Skov, Rijutha Jaganathan, John D Thrower, Liv Hornekær
{"title":"H<sub>2</sub> catalysis through superhydrogenation of interstellar polycyclic aromatic hydrocarbons.","authors":"Frederik Doktor S Simonsen,&nbsp;Pernille A Jensen,&nbsp;Anders W Skov,&nbsp;Rijutha Jaganathan,&nbsp;John D Thrower,&nbsp;Liv Hornekær","doi":"10.1017/S1743921320000034","DOIUrl":"https://doi.org/10.1017/S1743921320000034","url":null,"abstract":"<p><p>Experimental data showing superhydrogation of neutral polycyclic aromatic hydrocarbons (PAHs) coronene, pentacene and pentacenequinone is presented. PAH monolayers were prepared on a highly oriented pyrolytic graphite surface and subsequently exposed to a beam of atomic hydrogen. The superhydrogenated PAH species were examined via temperature programmed desorption measurements. Stable intermediate superhydrogenation degrees as well as fully superhydrogenated species are observed and the initial reaction cross section for coronene has been determined.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"15 Suppl 350","pages":"264-266"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1743921320000034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38604835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Characterization of large carbonaceous molecules in cosmic dust analogues and meteorites. 宇宙尘埃类似物和陨石中碳质大分子的特征。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2019-04-01 Epub Date: 2020-10-12 DOI: 10.1017/S1743921319008354
Hassan Sabbah, Mickaël Carlos, Christine Joblin
{"title":"Characterization of large carbonaceous molecules in cosmic dust analogues and meteorites.","authors":"Hassan Sabbah, Mickaël Carlos, Christine Joblin","doi":"10.1017/S1743921319008354","DOIUrl":"10.1017/S1743921319008354","url":null,"abstract":"<p><p>We present a new experimental setup called AROMA (The Aromatic Research of Organics with Molecular Analyzer) based on the use of laser mass spectrometry techniques. We demonstrate the potential of AROMA for the analysis of meteoritic samples and cosmic dust analogues. Tens of peaks are identified in the mass spectra with notable discrepancies across the different samples. These discrepancies provide clues on the chemical history of each sample and are not a bias of our analysis. A double bound-equivalent (DBE) method is applied to sort the detected carbonaceous molecules into families of compounds. It reveals in addition of polycyclic aromatic hydrocarbons, the presence of other populations such as mixed aromatic-aliphatic species and carbon clusters.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"15 Suppl 350","pages":"103-106"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116311/pdf/EMS98807.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38676945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Circumstellar chemistry of Si-C bearing molecules in the C-rich AGB star IRC+10216. 富c AGB星IRC+10216中含Si-C分子的星周化学性质。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-08-01 Epub Date: 2019-12-30 DOI: 10.1017/S1743921318005410
L Velilla-Prieto, J Cernicharo, M Agúndez, J P Fonfría, A Castro-Carrizo, G Quintana-Lacaci, N Marcelino, M C McCarthy, C A Gottlieb, C Sánchez Contreras, K H Young, N A Patel, C Joblin, J A Martín-Gago
{"title":"Circumstellar chemistry of Si-C bearing molecules in the C-rich AGB star IRC+10216.","authors":"L Velilla-Prieto,&nbsp;J Cernicharo,&nbsp;M Agúndez,&nbsp;J P Fonfría,&nbsp;A Castro-Carrizo,&nbsp;G Quintana-Lacaci,&nbsp;N Marcelino,&nbsp;M C McCarthy,&nbsp;C A Gottlieb,&nbsp;C Sánchez Contreras,&nbsp;K H Young,&nbsp;N A Patel,&nbsp;C Joblin,&nbsp;J A Martín-Gago","doi":"10.1017/S1743921318005410","DOIUrl":"https://doi.org/10.1017/S1743921318005410","url":null,"abstract":"<p><p>Silicon carbide together with amorphous carbon are the main components of dust grains in the atmospheres of C-rich AGB stars. Small gaseous Si-C bearing molecules (such as SiC, SiCSi, and SiC<sub>2</sub>) are efficiently formed close to the stellar photosphere. They likely condense onto dust seeds owing to their highly refractory nature at the lower temperatures (i.e., below about 2500 K) in the dust growth zone which extends a few stellar radii from the photosphere. Beyond this region, the abundances of Si-C bearing molecules are expected to decrease until they are eventually reformed in the outer shells of the circumstellar envelope, owing to the interaction between the gas and the interstellar UV radiation field. Our goal is to understand the time-dependent chemical evolution of Si-C bond carriers probed by molecular spectral line emission in the circumstellar envelope of IRC+10216 at millimeter wavelengths.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"14 ","pages":"535-537"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1743921318005410","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37517364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Massive Star Mass-Loss Revealed by X-ray Observations of Young Supernovae. 年轻超新星的x射线观测揭示了大质量恒星的质量损失。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-08-01 Epub Date: 2019-12-30 DOI: 10.1017/s1743921318008438
Vikram V Dwarkadas
{"title":"Massive Star Mass-Loss Revealed by X-ray Observations of Young Supernovae.","authors":"Vikram V Dwarkadas","doi":"10.1017/s1743921318008438","DOIUrl":"https://doi.org/10.1017/s1743921318008438","url":null,"abstract":"<p><p>Massive stars lose a considerable amount of mass during their lifetime. When the star explodes as a supernova (SN), the resulting shock wave expands in the medium created by the stellar mass-loss. Thermal X-ray emission from the SN depends on the square of the density of the ambient medium, which in turn depends on the mass-loss rate (and velocity) of the progenitor wind. The emission can therefore be used to probe the stellar mass-loss in the decades or centuries before the star's death. We have aggregated together data available in the literature, or analysed by us, to compute the X-ray lightcurves of almost all young supernovae detectable in X-rays. We use this database to explore the mass-loss rates of massive stars that collapse to form supernovae. Mass-loss rates are lowest for the common Type IIP supernovae, but increase by several orders of magnitude for the highest luminosity X-ray SNe.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"14 Suppl 346","pages":"83-87"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/s1743921318008438","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39734256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Maser-emitting Structure and Time Variability of the SiS Lines J = 14 - 13 and 15 - 14 in IRC+10216.
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-08-01 Epub Date: 2019-12-30 DOI: 10.1017/S1743921318006178
J P Fonfría, M Fernández-López, J R Pardo, M Agúndez, C Sánchez Contreras, L Velilla-Prieto, J Cernicharo, M Santander-García, G Quintana-Lacaci, A Castro-Carrizo, S Curiel
{"title":"The Maser-emitting Structure and Time Variability of the SiS Lines <i>J</i> = 14 - 13 and 15 - 14 in IRC+10216.","authors":"J P Fonfría, M Fernández-López, J R Pardo, M Agúndez, C Sánchez Contreras, L Velilla-Prieto, J Cernicharo, M Santander-García, G Quintana-Lacaci, A Castro-Carrizo, S Curiel","doi":"10.1017/S1743921318006178","DOIUrl":"10.1017/S1743921318006178","url":null,"abstract":"<p><p>AGB stars are important contributors of processed matter to the ISM. However, the physical and chemical mechanisms involved in its ejection are still poorly known. This process is expected to have remarkable effects in the innermost envelope, where the dust grains are formed, the gas is accelerated, the chemistry is active, and the radiative excitation becomes important. A good tracer of this region in C-rich stars is SiS, an abundant refractory molecule that can display maser lines, very sensitive to changes in the physical conditions. We present high angular resolution interferometer observations (HPBW ≳ <math> <mrow><msubsup><mn>0</mn> <mo>.</mo> <mrow><mo>″</mo></mrow> </msubsup> <mn>25</mn></mrow> </math> ) of the <i>v</i> = 0 <i>J</i> = 14 - 13 and 15 - 14 SiS maser lines towards the archetypal AGB star IRC+10216, carried out with CARMA and ALMA to explore the inner 1″ region around the central star. We also present an ambitious monitoring of these lines along one single pulsation period carried out with the IRAM 30 m telescope.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"14 Suppl 343","pages":"398-399"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7617088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143568845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Dynamics, temperature, chemistry, and dust: Ingredients for a self-consistent AGB wind. 动态、温度、化学和灰尘:自一致AGB风的成分。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-08-01 Epub Date: 2019-12-30 DOI: 10.1017/S1743921318005094
J Boulangier, D Gobrecht, L Decin
{"title":"Dynamics, temperature, chemistry, and dust: Ingredients for a self-consistent AGB wind.","authors":"J Boulangier,&nbsp;D Gobrecht,&nbsp;L Decin","doi":"10.1017/S1743921318005094","DOIUrl":"https://doi.org/10.1017/S1743921318005094","url":null,"abstract":"<p><p>Understanding Asymptotic Giant Branch (AGB) stars is important as they play a vital role in the chemical life cycle of galaxies. AGB stars are in a phase of their life time where they have almost ran out of fuel and are losing vast amounts of material to their surroundings, via stellar winds. As this is an evolutionary phase of low mass stars, almost all stars go through this phase making them one of the main contributors to the chemical enrichment of galaxies. It is therefore important to understand what kind of material is being lost by these stars, and how much and how fast. This work summarises the steps we have taken towards developing a self-consistent AGB wind model. We improve on current models by firstly coupling chemical and hydrodynamical evolution, and secondly by upgrading the nucleation theory framework to investigate the creation of TiO<sub>2</sub>, SiO, MgO, and Al<sub>2</sub>O<sub>3</sub> clusters.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"14 ","pages":"129-133"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1743921318005094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37517363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Triggered Star Formation inside the Shell of a Wolf-Rayet Bubble as the Origin of the Solar System. 太阳系起源于Wolf Rayet气泡外壳内的触发恒星形成。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-08-01 Epub Date: 2020-01-13
Vikram V Dwarkadas, Nicolas Dauphas, Bradley Meyer, Peter Boyajian, Michael Bojazi
{"title":"Triggered Star Formation inside the Shell of a Wolf-Rayet Bubble as the Origin of the Solar System.","authors":"Vikram V Dwarkadas, Nicolas Dauphas, Bradley Meyer, Peter Boyajian, Michael Bojazi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A constraint on Solar System formation is the high <sup>26</sup>Al/<sup>27</sup>Al abundance ratio, 17 times higher than the average Galactic ratio, while the <sup>60</sup>Fe/<sup>56</sup>Fe value was lower than the Galactic value. This challenges the assumption that a nearby supernova was responsible for the injection of these short-lived radionuclides into the early Solar System. We suggest that the Solar System was formed by triggered star formation at the edge of a Wolf-Rayet (W-R) bubble. We discuss the details of various processes within the model using numerical simulations, and analytic and semi-analytic calculations, and conclude that it is a viable model that can explain the initial abundances of <sup>26</sup>Al and <sup>60</sup>Fe. We estimate that 1%-16% of all Sun-like stars could have formed in such a setting.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"14 S345","pages":"78-82"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6425492/pdf/nihms-1523334.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41124817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Building a Large Solar Analog Sample Using K2. 利用K2构建大型太阳模拟样品。
Proceedings of the International Astronomical Union. International Astronomical Union Pub Date : 2018-02-01 Epub Date: 2018-11-27 DOI: 10.1017/S1743921318001230
Derek L Buzasi
{"title":"Building a Large Solar Analog Sample Using K2.","authors":"Derek L Buzasi","doi":"10.1017/S1743921318001230","DOIUrl":"https://doi.org/10.1017/S1743921318001230","url":null,"abstract":"<p><p>We have begun a project aimed at providing a large consistent set of well- vetted solar analogs in order to address questions of stellar rotation, activity, dynamos, and gyrochronology. We make use of the K2 mission fields to obtain precise photometric time series, supplemented by ground-based photometric and spectroscopic data for promising candidates. From this data we will derive rotation periods, spot coverages, and flare rates for a well- defined and well-calibrated sample of solar analogs.</p>","PeriodicalId":74548,"journal":{"name":"Proceedings of the International Astronomical Union. International Astronomical Union","volume":"13 ","pages":"233-234"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1743921318001230","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36842883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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