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Physical Sciences and Mathematics Commons™
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- Keyword
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- Astronautics (8)
- Astronomy (8)
- Science (8)
- Technology (8)
- Methods: statistical (2)
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- Stars: evolution (2)
- Techniques: photometric (2)
- Clusters: individual (Hyades (1)
- Galaxies : individual (3C 390.3) (1)
- Galaxies: Seyfert (1)
- Galaxies: active (1)
- Galaxies: individual (M31) (1)
- Galaxy: formation (1)
- Gamma ray bursts (1)
- Globular clusters: general (1)
- Hertzsprung-Russell and colour-magnitude diagrams (1)
- Kelvin-Helmholtz instability (1)
- M67 (1)
- Magnetopause (1)
- Methods: data analysis (1)
- NGC 188 (1)
- NGC 2168 and NGC 2477) (1)
- Novae - cataclysmic variables (1)
- Reconnection (1)
- Solar-wind-magetnosphere coupling (1)
- Stars: atmospheres (1)
- Stars: fundamental parameters (1)
- Stars: individual (M31N 2008-12a) (1)
- Techniques: spectroscopic (1)
- Ultraviolet: stars (1)
Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
Density And Magnetic Field Asymmetric Kelvin‐Helmholtz Instability, Xuanye Ma, Peter Delamere, Katariina Nykyri, Antonius Otto, Stefan Eriksson, Lihui Chai, Brandon Burkholder, Andrew Dimmock, Yu-Lun Liou, Shiva Kavosi
Density And Magnetic Field Asymmetric Kelvin‐Helmholtz Instability, Xuanye Ma, Peter Delamere, Katariina Nykyri, Antonius Otto, Stefan Eriksson, Lihui Chai, Brandon Burkholder, Andrew Dimmock, Yu-Lun Liou, Shiva Kavosi
Publications
The Kelvin‐Helmholtz (KH) instability can transport mass, momentum, magnetic flux, and energy between the magnetosheath and magnetosphere, which plays an important role in the solar‐wind‐ magnetosphere coupling process for different planets. Meanwhile, strong density and magnetic field asymmetry are often present between the magnetosheath (MSH) and magnetosphere (MSP), which could affect the transport processes driven by the KH instability. Our magnetohydrodynamics simulation shows that the KH growth rate is insensitive to the density ratio between the MSP and the MSH in the compressible regime, which is different than the prediction from linear incompressible theory. When the interplanetary magnetic field (IMF) …
Bayesian Hierarchical Modelling Of Initial-Final Mass Relations Across Star Clusters, Shijing Si, David A. Van Dyk, Ted Von Hippel, Elliot Robinson, Elizabeth Jeffery, David C. Stenning
Bayesian Hierarchical Modelling Of Initial-Final Mass Relations Across Star Clusters, Shijing Si, David A. Van Dyk, Ted Von Hippel, Elliot Robinson, Elizabeth Jeffery, David C. Stenning
Publications
The initial-final mass relation (IFMR) of white dwarfs (WDs) plays an important role in stellar evolution. To derive precise estimates of IFMRs and explore how they may vary among star clusters, we propose a Bayesian hierarchical model that pools photometric data from multiple star clusters. After performing a simulation study to show the benefits of the Bayesian hierarchical model, we apply this model to five star clusters: the Hyades, M67, NGC 188, NGC 2168, and NGC 2477, leading to reasonable and consistent estimates of IFMRs for these clusters. We illustrate how a cluster-specific analysis of NGC 188 using its own …
Breaking The Habit: The Peculiar 2016 Eruption Of The Unique Recurrent Nova M31n 2008-12a, M. Henze, T. D. Oswalt, M. J. Darnley, S. C. Williams, M. Kato, Et Al.
Breaking The Habit: The Peculiar 2016 Eruption Of The Unique Recurrent Nova M31n 2008-12a, M. Henze, T. D. Oswalt, M. J. Darnley, S. C. Williams, M. Kato, Et Al.
Publications
Since its discovery in 2008, the Andromeda galaxy nova M31N 2008-12a has been observed in eruption every single year. This unprecedented frequency indicates an extreme object, with a massive white dwarf and a high accretion rate, which is the most promising candidate for the single-degenerate progenitor of a Type Ia supernova known to date. The previous three eruptions of M31N 2008-12a have displayed remarkably homogeneous multiwavelength properties: (i) from a faint peak, the optical light curve declined rapidly by two magnitudes in less than two days, (ii) early spectra showed initial high velocities that slowed down significantly within days and …
Precise Ages Of Field Stars From White Dwarf Companions, M. Fouesneau, H-W. Rix, T. Von Hippel, D. W. Hogg, H. Tian
Precise Ages Of Field Stars From White Dwarf Companions, M. Fouesneau, H-W. Rix, T. Von Hippel, D. W. Hogg, H. Tian
Publications
Observational tests of stellar and Galactic chemical evolution call for the joint knowledge of a star’s physical parameters, detailed element abundances, and precise age. For cool main-sequence (MS) stars the abundances of many elements can be measured from spectroscopy, but ages are very hard to determine. The situation is different if the MS star has a white dwarf (WD) companion and a known distance, as the age of such a binary system can then be determined precisely from the photometric properties of the cooling WD. As a pilot study for obtaining precise age determinations of field MS stars, we identify …
Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of From the Realm of the Nebulae to Populations of Galaxies : Dialogues on a Century of Research, Astrophysics and Space Science Library, 435. by Mauro D'Onofrio, Roberto Rampazzo, and Simone Zaggia Springer, 2016 785p bibl index afp, 9783319310046 $279.00, 9783319310060 $219.00
Bayesian Analysis Of Two Stellar Populations In Galactic Globular Clusters – Iii. Analysis Of 30 Clusters, R. Wagner-Kaiser, D. C. Stenning, A Sarajedini, Ted Von Hippel, D. A. Van Dyk, E. Robinson, W. H. Jefferys
Bayesian Analysis Of Two Stellar Populations In Galactic Globular Clusters – Iii. Analysis Of 30 Clusters, R. Wagner-Kaiser, D. C. Stenning, A Sarajedini, Ted Von Hippel, D. A. Van Dyk, E. Robinson, W. H. Jefferys
Publications
We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of 30 Galactic globular clusters to characterize two distinct stellar populations. A sophisticated Bayesian technique is employed to simultaneously sample the joint posterior distribution of age, distance, and extinction for each cluster, as well as unique helium values for two populations within each cluster and the relative proportion of those populations. We find the helium differences among the two populations in the clusters fall in the range of ∼0.04 to 0.11. Because adequate models varying in carbon, nitrogen, and oxygen are not presently available, we …
Book Review: How Do You Find An Exoplanet?, T. D. Oswalt
Book Review: How Do You Find An Exoplanet?, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of How Do You Find an Exoplanet? by John Asher Johnson. Princeton, 2016 178p bibl index afp, 9780691156811 $35.00, 9781400873999
New Halo White Dwarf Candidates In The Sloan Digital Sky Survey, Kyra Dame, A. Gianninas, Mukremin Kilic, Jeffrey A. Munn, Warren R. Brown, Kurtis A. Williams, Ted Von Hippel, Hugh C. Harris
New Halo White Dwarf Candidates In The Sloan Digital Sky Survey, Kyra Dame, A. Gianninas, Mukremin Kilic, Jeffrey A. Munn, Warren R. Brown, Kurtis A. Williams, Ted Von Hippel, Hugh C. Harris
Publications
We present optical spectroscopy and near-infrared photometry of 57 faint (g = 19–22) high proper motion white dwarfs identified through repeat imaging of ≈3100 deg2 of the Sloan Digital Sky Survey footprint by Munn et al. We use ugriz and JHphotometry to perform a model atmosphere analysis, and identify 10 ultracool white dwarfs with Teff < 4000 K, including the coolest pure H atmosphere white dwarf currently known, J1657+2638, with Teff = 3550 ± 100 K. The majority of the objects with cooling ages larger than 9 Gyr display thick disc kinematics and constrain the age of the thick disc to ≥11 Gyr. There are four white dwarfs in our sample with …
Book Review: The Cambridge Atlas Of Herschel Objects, T. D. Oswalt
Book Review: The Cambridge Atlas Of Herschel Objects, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of The Cambridge Atlas of Herschel Objects by James Mullaney and Wil Tirion Cambridge, 2011 183p, 0521138175 $35.00, 9780521138178 $35.00.
Book Review: Guide To Observing Deep-Sky Objects: A Complete Global Resource For Astronomers, T. D. Oswalt
Book Review: Guide To Observing Deep-Sky Objects: A Complete Global Resource For Astronomers, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Guide to Observing Deep-Sky Objects : a Complete Global Resource for Astronomers by Jeff A. Farinacci. Springer, 2007 189p, 9780387728506 $29.95
Book Review: Evolution Of Stars And Stellar Populations, T. D. Oswalt
Book Review: Evolution Of Stars And Stellar Populations, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Evolution of Stars and Stellar Populations by Maurizio Salaris and Santi Cassisi Wiley, 2005 374p, 047009219X $150.00, 047009219X $60.00
Book Review: Sky Vistas: Astronomy For Binoculars And Richestfield Telescopes, T. D. Oswalt
Book Review: Sky Vistas: Astronomy For Binoculars And Richestfield Telescopes, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Sky Vistas : Astronomy for Binoculars and Richestfield Telescopes by Craig Crossen and Gerald Rhemann Springer, 2004 279p, 3211008519 $69.95
Book Review: The Observing Guide To The Messier Marathon: A Handbook And Atlas, T. D. Oswalt
Book Review: The Observing Guide To The Messier Marathon: A Handbook And Atlas, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of The Observing Guide to the Messier Marathon : a Handbook and Atlas by Don Machholz. Cambridge, 2002 157p, 0-521-80386-1 $25.00.
Book Review: Flash!: The Hunt For The Biggest Explosions In The Universe, T. D. Oswalt
Book Review: Flash!: The Hunt For The Biggest Explosions In The Universe, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Flash! : the hunt for the biggest explosions in the universe by Govert Schilling. tr. by Naomi Greenberg-Slovin Cambridge, 2002 291p, 0-521-80053-6 $28.00
Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xii. Ground-Based Monitoring Of 3c 390.3, M. Dietrich, Terry D. Oswalt, B. M. Peterson, P. Albrecht, M. Altmann, Et Al.
Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xii. Ground-Based Monitoring Of 3c 390.3, M. Dietrich, Terry D. Oswalt, B. M. Peterson, P. Albrecht, M. Altmann, Et Al.
Publications
Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V, R, and I), the spectrophotometric optical continuum flux and the Fλ(5177 Å),integrated emission-line fluxes of Hᵪ Hβ, Hᵧ, He I λ5876 and He II λ4686 all show a nearly monotonic increase with episodes of milder short-term variations superposed. The amplitude of the continuum variations increases with decreasing wavelength (4400-9000 Å). The optical continuum variations follow the variations in the ultraviolet and X-ray with time delays, measured from the centroids of the cross-correlation functions, typically around …