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arXiv 2017年

作者： Arcavi, Iair Howell, D. Andrew Kasen, Daniel Bildsten, Lars Hosseinzadeh, Griffin McCully, Curtis Wong, Zheng Chuen Katz, Sarah Rebekah Gal-Yam, Avishay Sollerman, Jesper Taddia, Francesco Leloudas, Giorgos Fremling, Christoffer Nugent, Peter E. Horesh, Assaf Mooley, Kunal Rumsey, Clare Cenko, S. Bradley Graham, Melissa L. Perley, Daniel A. Nakar, Ehud Shaviv, Nir J. Bromberg, Omer Shen, Ken J. Ofek, Eran O. Cao, Yi Wang, Xiaofeng Huang, Fang Rui, Liming Zhang, Tianmeng Li, Wenxiong Li, Zhitong Zhang, Jujia Valenti, Stefano Guevel, David Shappee, Benjamin Kochanek, Christopher S. Holoien, Thomas W.-S. Filippenko, Alexei V. Fender, Rob Nyholm, Anders Yaron, Ofer Kasliwal, Mansi M. Sullivan, Mark Blagorodnova, Nadja Walters, Richard S. Lunnan, Ragnhild Khazov, Danny Andreoni, Igor Laher, Russ R. Konidaris, Nick Wozniak, Przemek Bue, Brian Las Cumbres Observatory GoletaCA93117 United States Kavli Institute for Theoretical Physics University of California Santa BarbaraCA93106 United States Department of Physics University of California Santa BarbaraCA93106 United States Nuclear Science Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Physics University of California BerkeleyCA94720 United States Department of Astronomy University of California BerkeleyCA94720-3411 United States Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-10691 Sweden Dark Cosmology Centre Niels Bohr Institute University of Copenhagen Juliane Maries vej 30 Copenhagen2100 Denmark Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Racah Institute of Physics Hebrew University of Jerusalem Jerusalem91904 Israel Department of Physics Astrophysics University of Oxford Denys Wilkinson Building OxfordOX1 3RH United Kingdom Astrophysics Group Cavendish Laboratory 19 J. J. Thomson Avenue CambridgeCB3 0HE United Kingdom Astrophysics Science Division NASA Goddard Space Flight Center Code 661 GreenbeltMD20771 United States Joint Space-Science Institute University of Maryland College ParkMD20742 United States Department of Astronomy University of Washington Box 351580 U.W. SeattleWA98195-1580 United States Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel eScience Institute University of Washington Box 351570 U.W. SeattleWA98195-1580 United States Tsinghua University Beijing100084 China Key Laboratory of Optical Astronomy National Astronomical Observatories of China Chinese

Every supernova hitherto observed has been considered to be the terminal explosion of a star. Moreover, all supernovae with absorption lines in their spectra show those lines decreasing in velocity over time, as the ejecta expand and thin, revealing slower moving material that was previously hidden. In addition, every supernova that exhibits the absorption lines of hydrogen has one main light-curve peak, or a plateau in luminosity, lasting approximately 100 days before declining1. Here we report observations of iPTF14hls, an event that has spectra identical to a hydrogen-rich core-collapse supernova, but characteristics that differ extensively from those of known supernovae. The light curve has at least five peaks and remains bright for more than 600 days;the absorption lines show little to no decrease in velocity;and the radius of the line-forming region is more than an order of magnitude bigger than the radius of the photosphere derived from the continuum emission. These characteristics are consistent with a shell of several tens of solar masses ejected by the star at supernova-level energies a few hundred days before a terminal explosion. Another possible eruption was recorded at the same position in 1954. Multiple energetic pre-supernova eruptions are expected to occur in stars of 95–130 solar masses, which experience the pulsational pair instability2, 3, 4, 5. That model, however, does not account for the continued presence of hydrogen, or the energetics observed here. Another mechanism for the violent ejection of mass in massive stars may be required. Copyright © 2017, The Authors. All rights reserved.

关键词： Supernovae

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Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the Kepler 2 Observations

arXiv

引用

arXiv 2018年

作者： Li, W. Wang, X. Vinkó, J. Mo, J. Hosseinzadeh, G. Sand, D.J. Zhang, J. Lin, H. Zhang, T. Wang, L. Zhang, J. Chen, Z. Xiang, D. Rui, L. Huang, F. Li, X. Zhang, X. Li, L. Baron, E. Derkacy, J.M. Zhao, X. Sai, H. Zhang, K. Wang, L. Howell, D.A. McCully, C. Arcavi, I. Valenti, S. Hiramatsu, D. Burke, J. Rest, A. Garnavich, P. Tucker, B.E. Narayan, G. Shaya, E. Margheim, S. Zenteno, A. Villar, A. Dimitriadis, G. Foley, R.J. Pan, Y.-C. Coulter, D.A. Fox, O.D. Jha, S.W. Jones, D.O. Kasen, D.N. Kilpatrick, C.D. Piro, A.L. Riess, A.G. Rojas-Bravo, C. Shappee, B.J. Holoien, T.W.-S. Stanek, K.Z. Drout, M.R. Auchettl, K. Kochanek, C.S. Brown, J.S. Bose, S. Bersier, D. Brimacombe, J. Chen, P. Dong, S. Holmbo, S. Muñoz, J.A. Mutel, R.L. Post, R.S. Prieto, J.L. Shields, J. Tallon, D. Thompson, T.A. Vallely, P.J. Villanueva, S. Smartt, S.J. Smith, K.W. Chambers, K.C. Flewelling, H.A. Huber, M.E. Magnier, E.A. Waters, C.Z. Schultz, A.S.B. Bulger, J. Lowe, T.B. Willman, M. Sárneczky, K. Pál, A. Wheeler, J.C. Bódi, A. Bognár, Zs Csák, B. Cseh, B. Csörnyei, G. Hanyecz, O. Ignácz, B. Kalup, Cs Könyves-Tóth, R. Kriskovics, L. Ordasi, A. Rajmon, I. Sódor, A. Szabó, R. Szakáts, R. Zsidi, G. Milne, P. Andrews, J.E. Smith, N. Bilinski, C. Brown, P.J. Nordin, J. Williams, S.C. Galbany, L. Palmerio, J. Hook, I.M. Inserra, C. Maguire, K. Cartier, Régis Razza, A. Gutiérrez, C.P. Hermes, J.J. Reding, J.S. Kaiser, B.C. Tonry, J.L. Heinze, A.N. Denneau, L. Weiland, H. Stalder, B. Barentsen, G. Dotson, J. Barclay, T. Gully-Santiago, M. Hedges, C. Cody, A.M. Howell, S. Coughlin, J. van Cleve, J.E. Cardoso, J. Vinícius de Miranda Larson, K.A. McCalmont-Everton, K.M. Peterson, C.A. Ross, S.E. Reedy, L.H. Osborne, D. McGinn, C. Kohnert, L. Migliorini, L. Wheaton, A. Spencer, B. Labonde, C. PTSS / TNTS LCO KEGS UCSC ASAS-SN Pan-STARRS University of Arizona Swift ePESSTO University of North Carolina ATLAS Mission Team spacecraft team Tsinghua University Beijing100084 China Las Cumbres Observatory 6740 Cortona Dr Ste 102 GoletaCA93117-5575 United States Konkoly Observatory MTA CSFK Konkoly Thege M. ut 15-17 Budapest1121 Hungary Department of Optics & Quantum Electronics University of Szeged Dom ter 9 Szeged6720 Hungary Department of Astronomy University of Texas at Austin AustinTX78712 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Harvard-Smithsonian Center for Astrophysics 60 Garden Street CambridgeMA02138 United States Steward Observatory University of Arizona 933 North Cherry Avenue Rm. N204 TucsonAZ85721-0065 United States Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China National Astronomical Observatory of China Chinese Academy of Sciences Beijing100012 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210034 China George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University Department of Physics and Astronomy 4242 TAMU College StationTX77843 United States Department of Astronomy School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Homer L. Dodge Department of Physics and Astronomy University of Oklahoma NormanOK United States School of Science Tianjin University of Technology Tianjin300384 China Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for Astronomy Camino El Observatorio 1515 SantiagoLas Condes Chile Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Te

Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically-confirmed type Ia supernova (SN Ia) observed in the Kepler field. The Kepler data revealed an excess emission in its early light curve, allowing to place interesting constraints on its progenitor system (Dimitriadis et al. 2018;Shappee et al. 2018b). Here, we present extensive optical, ultraviolet, and near-infrared photometry, as well as dense sampling of optical spectra, for this object. SN 2018oh is relatively normal in its photometric evolution, with a rise time of 18.3±0.3 days and ∆m15(B) = 0.96±0.03 mag, but it seems to have bluer B − V colors. We construct the "uvoir" bolometric light curve having peak luminosity as 1.49×1043erg s−1, from which we derive a nickel mass as 0.55±0.04M☉ by fitting radiation diffusion models powered by centrally located 56Ni. Note that the moment when nickel-powered luminosity starts to emerge is +3.85 days after the first light in the Kepler data, suggesting other origins of the early-time emission, e.g., mixing of 56Ni to outer layers of the ejecta or interaction between the ejecta and nearby circumstellar material or a non-degenerate companion star. The spectral evolution of SN 2018oh is similar to that of a normal SN Ia, but is characterized by prominent and persistent carbon absorption features. The C II features can be detected from the early phases to about 3 weeks after the maximum light, representing the latest detection of carbon ever recorded in a SN Ia. This indicates that a considerable amount of unburned carbon exists in the ejecta of SN 2018oh and may mix into deeper layers. Copyright © 2018, The Authors. All rights reserved.

关键词： Supernovae

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MULTI-WAVELENGTH OBSERVATIONS OF GRB 111228A AND IMPLICATIONS FOR THE FIREBALL AND ITS ENVIRONMENT

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The Astrophysical Journal 2016年第2期817卷

作者： Li-Ping Xin Yuan-Zhu Wang Ting-Ting Lin En-Wei Liang Hou-Jun Lü Shu-Qing Zhong Yuji Urata Xiao-Hong Zhao Chao Wu Jian-Yan Wei Kui-Yun Huang Yu-Lei Qiu Jin-Song Deng Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences China GXU-NAOC Center for Astrophysics and Space Sciences Department of Physics Guangxi University Nanning 530004 China Guangxi Key Laboratory for the Relativistic Astrophysics Nanning 530004 China Institute of Astronomy National Central University Chung-Li 32054 Taiwan Academia Sinica Institute of Astronomy and Astrophysics Taipei 106 Taiwan Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 650011 Kunming China Key Laboratory for the Structure and Evolution of Celestial Bodies Chinese Academy of Sciences P.O. Box 110 650011 Kunming China Department of Mathematics and Science National Taiwan Normal University Lin-kou District New Taipei City 24449 Taiwan

Observations of very early multi-wavelength afterglows are critical to reveal the properties of the radiating fireball and its environment as well as the central engine of gamma-ray bursts (GRBs). We report our optical observations of GRB 111228A from 95 s to about 50 hr after the burst trigger and investigate its properties of the prompt gamma-rays and the ambient medium using our data and the data from the Swift and Fermi missions. Our joint optical and X-ray spectral fits to the afterglow data show that the ambient medium features a low dust-to-gas ratio. Incorporating the energy injection effect, our best fit to the afterglow light curves with the standard afterglow model via the Markov Chain Monte Carlo technique shows that , , cm−3. The low medium density likely implies that the afterglow jet may be in a halo or in a hot ISM. A chromatic shallow decay segment observed in the optical and X-ray bands is well explained with the long-lasting energy injection from the central engine, which would be a magnetar with a period of about 1.92 ms inferred from the data. The Ep of its time-integrated prompt gamma-ray spectrum is ~26 KeV. Using the initial Lorentz factor () derived from our afterglow model fit, it is found that GRB 111228A satisfies the relation and bridges the typical GRBs and low luminosity GRBs in this relation.

关键词： gamma-ray burst: individual (GRB 130702A, GRB 111228A)

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Asteroseismology of DAV white dwarf stars and G29–38

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Research in Astronomy and Astrophysics 2013年第12期13卷 1438-1444页

作者： Yan-Hui Chen Yan Li Yunnan Astronomical Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

Asteroseismology is a powerful tool used for detecting the inner structure of stars, which is also widely used to study white dwarfs. We discuss the asteroseismology of DAV stars. The period-to-period fitting method is discussed in detail, including its reliability in detecting the inner structure of DAV stars. If we assume that all observed modes of some DAV stars are the l = I cases, the errors associated with model fitting will be always large. If we assume that the observed modes are com- posed of I = 1 and 2 modes, the errors associated with model fitting in this case will be small. However, there will be modes identified as l = 2 that do not have ob- served quintuplets. G29-38 has been observed spectroscopically and photometrically for many years. Thompson et al. made 1 modes identifications in the star through the limb darkening effect. With 11 known I modes, we also study the asteroseismology of G29-38, which reduces the blind l fittings and is a fair choice. Unfortunately, our two best-fitting models are not in line with the previous atmospheric results. Based on factors like only a few observed modes, stability and identification of eigenmodes, identification of spherical degrees, construction of physical and realistic models and so on, detecting the inner structure of DAV stars by asteroseismology needs further development.

关键词： stars： oscillations （including pulsations） - stars： individual （G29-38）- white dwarfs

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K2 Observations of SN 2018oh Reveal a Two-Component Rising Light Curve for a Type Ia Supernova

arXiv

引用

arXiv 2018年

作者： Dimitriadis, G. Foley, R.J. Rest, A. Kasen, D. Piro, A.L. Polin, A. Jones, D.O. Villar, A. Narayan, G. Coulter, D.A. Kilpatrick, C.D. Pan, Y.-C. Rojas-Bravo, C. Fox, O.D. Jha, S.W. Nugent, P.E. Riess, A.G. Scolnic, D. Drout, M.R. Barentsen, G. Dotson, J. Gully-Santiago, M. Hedges, C. Cody, A.M. Barclay, T. Howell, S. Garnavich, P. Tucker, B.E. Shaya, E. Mushotzky, R. Olling, R.P. Margheim, S. Zenteno, A. Coughlin, J. van Cleve, J.E. Cardoso, J. Vinícius de Miranda Larson, K.A. McCalmont-Everton, K.M. Peterson, C.A. Ross, S.E. Reedy, L.H. Osborne, D. McGinn, C. Kohnert, L. Migliorini, L. Wheaton, A. Spencer, B. Labonde, C. Castillo, G. Beerman, G. Steward, K. Hanley, M. Larsen, R. Gangopadhyay, R. Kloetzel, R. Weschler, T. Nystrom, V. Moffatt, J. Redick, M. Griest, K. Packard, M. Muszynski, M. Kampmeier, J. Bjella, R. Flynn, S. Elsaesser, B. Chambers, K.C. Flewelling, H.A. Huber, M.E. Magnier, E.A. Waters, C.Z. Schultz, A.S.B. Bulger, J. Lowe, T.B. Willman, M. Smartt, S.J. Smith, K.W. Points, S. Strampelli, G.M. Brimacombe, J. Chen, P. Muñoz, J.A. Mutel, R.L. Shields, J. Vallely, P.J. Jr, S. Villanueva Li, W. Wang, X. Zhang, J. Lin, H. Mo, J. Zhao, X. Sai, H. Zhang, X. Zhang, K. Zhang, T. Wang, L. Zhang, J. Baron, E. DerKacy, J.M. Li, L. Chen, Z. Xiang, D. Rui, L. Wang, L. Huang, F. Li, X. Hosseinzadeh, G. Howell, D.A. Arcavi, I. Hiramatsu, D. Burke, J. Valenti, S. Tonry, J.L. Denneau, L. Heinze, A.N. Weiland, H. Stalder, B. Vinkó, J. Sárneczky, K. Pál, A. Bódi, A. Bognár, Zs. Csák, B. Cseh, B. Csörnyei, G. Hanyecz, O. Ignácz, B. Kalup, Cs. Könyves-Tóth, R. Kriskovics, L. Ordasi, A. Rajmon, I. Sódor, A. Szabó, R. Szakáts, R. Zsidi, G. Williams, S.C. Nordin, J. Cartier, R. Frohmaier, C. Galbany, L. Gutiérrez, C.P. Hook, I. Inserra, C. Smith, M. Sand, D.J. Andrews, J.E. Smith, N. Bilinski, C. Department of Astronomy and Astrophysics University of California Santa CruzCA95064 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Department of Physics and Astronomy Johns Hopkins University BaltimoreMD21218 United States Department of Astronomy University of California BerkeleyCA94720-3411 United States Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States Observatories of the Carnegie Institution for Science 813 Santa Barbara St. PasadenaCA91101 United States Department of Astronomy University of California BerkeleyCA94720-3411 United States Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Harvard-Smithsonian Center for Astrophysics 60 Garden Street CambridgeMA02138 United States Department of Physics and Astronomy Rutgers State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States NASA Ames Research Center Moffett FieldCA94035 United States Bay Area Environmental Research Institute P.O. Box 25 Moffett FieldCA94035 United States NASA Goddard Space Flight Center 8800 Greenbelt Rd GreenbeltMD20771 United States University of Maryland Baltimore County 1000 Hilltop Cir BaltimoreMD21250 United States Department of Physics University of Notre Dame 225 Nieuwland Science Hall Notre DameIN46556-5670 United States Research School of Astronomy and Astrophysics Mount Stromlo Observatory Australian National University CanberraACT2611 Australia National Centre for the Public Awareness of Science Australian National University CanberraACT2611 Australia Australia Astronomy Department University of Maryland College ParkMD20742-2421 United States Gemini Observatory La Serena Chile Cerro Tololo Inter-American Observatory Casilla 603 La Serena Chile SETI Institute 189 Bernardo Avenue Mountain ViewCA94043

We present an exquisite, 30-min cadence Kepler (K2) light curve of the Type Ia supernova (SN Ia) 2018oh (ASASSN-18bt), starting weeks before explosion, covering the moment of explosion and the subsequent rise, and continuing past peak brightness. These data are supplemented by multi-color Pan-STARRS1 and CTIO 4-m DECam observations obtained within hours of explosion. The K2 light curve has an unusual two-component shape, where the flux rises with a steep linear gradient for the first few days, followed by a quadratic rise as seen for typical SNe Ia. This "flux excess" relative to canonical SN Ia behavior is confirmed in our i-band light curve, and furthermore, SN 2018oh is especially blue during the early epochs. The flux excess peaks 2.14±0.04 days after explosion, has a FWHM of 3.12±0.04 days, a blackbody temperature of T = 17, 500+11−9,000,500 K, a peak luminosity of 4.3±0.2×1037 erg s−1, and a total integrated energy of 1.27±0.01×1043 erg. We compare SN 2018oh to several models that may provide additional heating at early times, including collision with a companion and a shallow concentration of radioactive nickel. While all of these models generally reproduce the early K2 light curve shape, we slightly favor a companion interaction, at a distance of ∼2 × 1012 cm based on our early color measurements, although the exact distance depends on the uncertain viewing angle. Additional confirmation of a companion interaction in future modeling and observations of SN 2018oh would provide strong support for a single-degenerate progenitor system. Copyright © 2018, The Authors. All rights reserved.

关键词： Explosions

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Two particular EA-type binaries in the globular cluster ω Centauri

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Research in Astronomy and Astrophysics 2013年第7期13卷 827-834页

作者： Kai Li Sheng-Bang Qian National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

We analyzed the B and V light curves of two EA-type binaries V211 and NV358 for the first time using the Wilson-Devinney code. Our analysis shows that V211 is a typical Algol-type binary and NV358 is a well detached binary system. As the two binaries are definite members of ω Centauri due to their proper motion, we estimated their physical parameters, obtaining M1 = 1.13 4±0.03 M⊙, R1 = 0.98±0.01 R⊙, M2 = 0.33 ±0.01 M⊙ and R2 = 0.92 ±0.01 R⊙ forV211; M1 = 1.304-0.05 M⊙, R1 = 1.03±0.01 R⊙, M2 = 0.58±0.02 M⊙ and R2 = 0.78±0.01 R⊙ for NV358. On the color-magnitude diagram of ω Centauri, V211 is located in the faint blue straggler region and its primary component is more massive than a star at the main-sequence turnoff. Therefore, V211 is a blue straggler and was formed by mass transfer from the secondary component to the primary. The age of NV358 is less than 1.93 Gyr, indicating that it is much younger than the first generation of stars in ω Centaufi. Like NV364 in ω Centaufi, NV358 should be a second-generation binary.

关键词： galaxies： globular clusters： individual （ω Centauri） - stars： binaries：close - stars： binaries： eclipsing - stars： blue stragglers - stars： individual （V211 NV358）

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Dependence of low redshift Type Ia Supernovae luminosities on host galaxies

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Research in Astronomy and Astrophysics 2013年第9期13卷 1087-1096页

作者： Wen-Ke Liang Jian-Cheng Wang National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

We study the relation between Type Ia Supernovae （SNe Ia） and properties of their host galaxies using a large sample with low redshift. By examining the Hubble residuals of the entire sample from the best-fit cosmology, we show that SNe Ia in passive hosts are brighter than those in star-forming hosts after light curve correction at the 2. 1σ confidence level. We find that SNe Ia in high luminosity hosts are brighter after light-curve correction at the 〉 3σ confidence level. We also find that SNe Ia in large galaxies are brighter after light-curve correction at the ≥2σ confidence level. We demonstrate that the residuals depend linearly on host luminosity at a confidence of 4or or host size at a confidence of 3.3σ.

关键词： supernovae： general -- distance scale -- galaxies： classification

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Herschel and SCUBA-2 observations of dust emission in a sample of Planck cold clumps

arXiv

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arXiv 2017年

作者： Juvela, Mika He, Jinhua Pattle, Katherine Liu, Tie Bendo, George Eden, David J. Fehér, Orsolya Fich, Michel Fuller, Gary Hirano, Naomi Kim, Kee-Tae Li, Di Liu, Sheng-Yuan Malinen, Johanna Marshall, Douglas J. Paradis, Deborah Parsons, Harriet Pelkonen, Veli-Matti Rawlings, Mark G. Ristorcelli, Isabelle Samal, Manash R. Tatematsu, Ken'ichi Thompson, Mark Traficante, Alessio Wang, Ke Ward-Thompson, Derek Wu, Yuefang Yi, Hee-Weon Yoo, Hyunju Department of Physics University of Helsinki P.O.Box 64 FI-00014 Finland Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for Astronomy Camino El Observatorio #1515 Las Condes Santiago Chile Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Jeremiah Horrocks Institute University of Central Lancashire PrestonPR1 2HE United Kingdom Korea Astronomy and Space Science Institute 776 Daedeokdaero Yuseong-gu Daejeon34055 Korea Republic of East Asian Observatory 660 N. A'ohōkū Place HiloHI96720-2700 United States UK ALMA Regional Centre Node Jodrell Bank Centre for Astrophysics University of Manchester Oxford Road ManchesterM13 9PL United Kingdom Astrophysics Research Institute Liverpool John Moores University Ic2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Konkoly Observatory Research Centre for Astronomy and Earth Sciences Hungarian Academy of Sciences Konkoly Thege Miklós út 15-17 BudapestH-1121 Hungary Eövös Loránd University Department of Astronomy Pázmány Péter sétány 1/A Budapest1117 Hungary Department of Physics and Astronomy University of Waterloo WaterlooONN2L 3G1 Canada Institute of Astronomy and Astrophysics Academia Sinica. 11F of Astronomy-Mathematics Building AS/NTU No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China Key Laboratory of Radio Astronomy Chinese Academy of Science Nanjing210008 China Institute of Physics I University of Cologne Germany Laboratoire AIM IRFU Service d'Astrophysique CEA DSM CNRS Université Paris Diderot Bât. 709 CEA-Saclay Gif-sur-

Context. Analysis of all-sky Planck submillimetre observations and the IRAS 100 µm data has led to the detection of a population of Galactic cold clumps. The clumps can be used to study star formation and dust properties in a wide range of Galactic environments. Aims. Our aim is to measure dust spectral energy distribution (SED) variations as a function of the spatial scale and the wavelength. Methods. We examine the SEDs at large scales using IRAS, Planck, and Herschel data. At smaller scales, we compare with JCMT/SCUBA-2 850 µm maps with Herschel data that are filtered using the SCUBA-2 pipeline. Clumps are extracted using the Fellwalker method and their spectra are modelled as modified blackbody functions. Results. According to IRAS and Planck data, most fields have dust colour temperatures TC ∼ 14 − 18 K and opacity spectral index values of β = 1.5 − 1.9. The clumps/cores identified in SCUBA-2 maps have T ∼ 13 K and similar β values. There are some indications of the dust emission spectrum becoming flatter at wavelengths longer than 500 µm. In fits involving Planck data, the significance is limited by the uncertainty of the corrections for CO line contamination. The fits to the SPIRE data give a median β value slightly above 1.8. In the joint SPIRE and SCUBA-2 850 µm fits the value decreases to β ∼1.6. Most of the observed T-β anticorrelation can be explained by noise. Conclusions. The typical submillimetre opacity spectral index β of cold clumps is found to be ∼1.7. This is above the values of diffuse clouds but lower than in some previous studies of dense clumps. There is only tentative evidence of T-β anticorrelation and β decreasing at millimetre wavelengths. Copyright © 2017, The Authors. All rights reserved.

关键词： Dust

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The low-mass classic Algol-type binary UU Leo revisited

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Research in Astronomy and Astrophysics 2013年第12期13卷 1471-1481页

作者： Yuan-Gui Yang School of Physics and Electronic Information Huaibei Normal University Key Laboratory of the Structure and Evolutionary of Celestial Objects Chinese Academy of Sciences

New multi-color photometry of the eclipsing binary UU Leo, acquired from 2010 to 2013, was carried out by using the 60-cm and 85-cm telescopes at the Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, the photometric solution was derived from BVR light curves. The results imply that UU Leo is a semi-detached Algol-type binary, with a mass ratio of q = 0.100（±0.002）. The change in orbital period was reanalyzed based on all available eclipsing times. The 0 - C curve could be described by an upward parabola superimposed on a quasi-sinusoidal curve. The period and semi-amplitudes are Pmod = 54.5（±1.1） yr and A = 0.0273d（±0.0015d）, which may be attributed to the light-time effect via the presence of an invisible third body. The long-term period increases at a rate of dR/dr=＋4.64（±0.14）×10^-7d yr^-1, which may be interpreted by the conserved mass being transferred from the secondary to the primary. With mass being transferred, the low-mass Algol-type binary UU Leo may evolve into a binary system with a main sequence star and a helium white dwarf.

关键词： stars （including multiple）： binaries： close -- stars： individual （UU Leo）

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High-resolution imaging of transiting extrasolar planetary systems (HITEP).

arXiv

引用

arXiv 2017年

作者： Evans, D.F. Southworth, J. Smalley, B. Jørgensen, U.G. Dominik, M. Andersen, M.I. Bozza, V. Bramich, D.M. Burgdorf, M.J. Ciceri, S. D’Ago, G. Jaimes, R. Figuera Gu, S.-H. Hinse, T.C. Henning, T.H. Hundertmark, M. Kains, N. Kerins, E. Korhonen, H. Kokotanekova, R. Kuffmeier, M. Longa-Peña, P. Mancini, L. MacKenzie, J. Popovas, A. Rabus, M. Rahvar, S. Sajadian, S. Snodgrass, C. Skottfelt, J. Surdej, J. Tronsgaard, R. Unda-Sanzana, E. von Essen, C. Wang, Yi-Bo Wertz, O. Astrophysics Group Keele University StaffordshireST5 5BG United Kingdom Niels Bohr Institute Centre for Star and Planet Formation University of Copenhagen Øster Voldgade 5 Copenhagen1350 - Denmark Centre for Exoplanet Science SUPA School of Physics & Astronomy University of St Andrews North Haugh St AndrewsKY16 9SS Dark Cosmology Centre Niels Bohr Institute University of Copenhagen Juliane Maries Vej 30 Copenhagen ØDK-2100 Dipartimento di Fisica "E.R. Caianiello" Università di Salerno Via Giovanni Paolo II 132 Fisciano84084 Italy Istituto Nazionale di Fisica Nucleare Sezione di Napoli Napoli Italy Universität Hamburg Faculty of Mathematics Informatics and Natural Sciences Department of Earth Sciences Meteorological Institute Bundesstraße 55 Hamburg20146 Germany Max Planck Institute for Astronomy Königstuhl 17 Heidelberg69117 Germany INAF-Osservatorio Astronomico di Capodimonte Salita Moiariello 16 Napoli80131 Italy European Southern Observatory Karl-Schwarzschild Straße 2 Garching bei München85748 Germany Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Korea Astronomy & Space Science Institute 776 Daedukdae-ro Yuseong-gu Daejeon305-348 Astronomisches Rechen-Institut Zentrum für Astronomie der Universität Heidelberg Mönchhofstr. 12-14 Heidelberg69120 Germany Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 Jodrell Bank Centre for Astrophysics School of Physics and Astronomy University of Manchester Oxford Road ManchesterM13 9PL United Kingdom Väisäläntie 20 PiikkiöFI-21500 Finland Max Planck Institute for Solar System Research Justus-von-LiebigWeg 3 Göttingen37077 Germany School of Physical Sciences Faculty of Science Technology Engineering and Mathematics Open University Walton Hall Milton KeynesMK7 6AA United Kingdom Unidad de Astronomía Fac. de Ciencias Básicas

Context. The formation and dynamical history of hot Jupiters is currently debated, with wide stellar binaries having been suggested as a potential formation pathway. Additionally, contaminating light from both binary companions and unassociated stars can significantly bias the results of planet characterisation studies, but can be corrected for if the properties of the contaminating star are known. Aims. We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light. Methods. We analyse lucky imaging observations of 97 Southern hemisphere exoplanet host stars, using the Two Colour Instrument on the Danish 1.54m telescope. For each detected companion star, we determine flux ratios relative to the planet host star in two passbands, and measure the relative position of the companion. The probability of each companion being physically associated was determined using our two-colour photometry. Results. A catalogue of close companion stars is presented, including flux ratios, position measurements, and estimated companion star temperature. For companions that are potential binary companions, we review archival and catalogue data for further evidence. For WASP-77AB and WASP-85AB, we combine our data with historical measurements to determine the binary orbits, showing them to be moderately eccentric and inclined to the line of sight (and hence planetary orbital axis). Combining our survey with the similar Friends of Hot Jupiters survey, we conclude that known hot Jupiter host stars show a deficit of high mass stellar companions compared to the field star population;however, this may be a result of the biases in detection and target selection by ground-based surveys. Copyright © 2017, The Authors

关键词： Extrasolar planets

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