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- Stars (8)
- Early-type stars (3)
- Flares (3)
- Fundamental parameters (3)
- Magnetic fields (3)
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- Massive stars (3)
- Outflows (3)
- AGB and post-AGB (2)
- Atmospheres (2)
- Interferometric techniques (2)
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- Mass-loss (2)
- Photosphere (2)
- Stars: massive (2)
- Stellar winds (2)
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- X-rays: stars (2)
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- Binaries: general (1)
- Cataclysmic variables (1)
- Cepheids (1)
- Chromosphere (1)
- Circumstellar matter (1)
- Curiosity (1)
- Delta2 Lyrae (1)
- Dynamical evolution and stability (1)
- Errata (1)
- GIS (1)
- Galaxies: evolution (1)
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Articles 1 - 24 of 24
Full-Text Articles in Physical Sciences and Mathematics
3d Mhd Models Of The Centrifugal Magnetosphere From A Massive Star With An Oblique Dipole Field, Asif Ud-Doula, Stanley P. Owocki, Marc Gagné, Simon Daley-Yates
3d Mhd Models Of The Centrifugal Magnetosphere From A Massive Star With An Oblique Dipole Field, Asif Ud-Doula, Stanley P. Owocki, Marc Gagné, Simon Daley-Yates
Earth & Space Sciences Faculty Publications
We present results from new self-consistent 3D magnetohydrodynamics(MHD)simulations of the magnetospheres from massive stars with a dipole magnetic axis that has a non-zero obliquity angle (β) to the star’s rotation axis. As an initial direct application, we compare the global structure of co-rotating discs for nearly aligned (β = 5◦) versus half-oblique (β = 45◦) models, both with moderately rapid rotation (∼0.5 critical). We find that accumulation surfaces broadly resemble the forms predicted by the analytical rigidly rotating magnetosphere model, but the mass buildup to near the critical level for centrifugal breakout against magnetic confinement distorts the field from the …
Delineating A Stream Network At Gale Crater, Mars, On Arcgis Pro: A Geographic Information Systems Approach, Elpidio Guzman De La Cruz
Delineating A Stream Network At Gale Crater, Mars, On Arcgis Pro: A Geographic Information Systems Approach, Elpidio Guzman De La Cruz
West Chester University Master’s Theses
The northwestern region of the Gale crater experienced flooding in the past. Delineation of stream networks for the northwestern region of Gale Crater, Mars employing geographic information systems (GIS) techniques is applied. The stream network produced by the algorithm in the study traverses the clay unit in Gediz Vallis, and visual HiRISE imagery analysis correlates with a topologic cross section of an inverted river channel of 750 meters wide and 90 meters deep. HiRISE imagery analysis further confirms a sulfate and clay stratigraphic unit in a stream 125 meters wide and 25 meters deep. Lastly, data smoothing procedures in the …
Losing The Dark: How Light Pollution Impacts Humans And The Environment, And What We Can Do To Win Back The Night, Marc Gagné
Sustainability Research & Practice Seminar Presentations
Professor Marc Gagne, Earth and Space Sciences - Losing the Dark: How light pollution impacts humans and the environment, and what we can do to win back the night
X-Ray Properties Of Early-Type Stars In The Tarantula Nebula From T-Rex, Paul A. Crowther, Patrick S. Broos, Leisa K. Townsley, Andy M. T. Pollock, Katie A. Tehrani, Marc Gagné
X-Ray Properties Of Early-Type Stars In The Tarantula Nebula From T-Rex, Paul A. Crowther, Patrick S. Broos, Leisa K. Townsley, Andy M. T. Pollock, Katie A. Tehrani, Marc Gagné
Earth & Space Sciences Faculty Publications
We reassess the historical L-X/L-Bol relation for early-type stars from a comparison between T-ReX, the Chandra ACIS X-ray survey of the Tarantula Nebula in the Large Magellanic Cloud (LMC), and contemporary spectroscopic analysis of massive stars obtained primarily from VLT/FLAMES, VLT/MUSE, and HST/STIS surveys. For 107 sources in common (some host to multiple stars), the majority of which are bolometrically luminous (40 per cent exceed 10(6)L(circle dot)), we find an average log L-X/L-Bol = -6.90 +/- 0.65. Excluding extreme systems Mk 34 (WN5h+WN5h), R140a (WC4+WN6+), and VFTS 399 (O9 IIIn+?), plus four WR sources with anomalously hard X-ray components (R130, …
Helium-Like X-Ray Line Complexes Show That The Hottest Plasma On The Zeta Supergiant Puppis Is In Its Wind, David H. Cohen, Ariel M. Overdorff, Maurice A. Leutenegger, Marc Gagné, Veronique Petit, Alexandre David-Uraz
Helium-Like X-Ray Line Complexes Show That The Hottest Plasma On The Zeta Supergiant Puppis Is In Its Wind, David H. Cohen, Ariel M. Overdorff, Maurice A. Leutenegger, Marc Gagné, Veronique Petit, Alexandre David-Uraz
Earth & Space Sciences Faculty Publications
We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest (T greater than or similar to 6 x 10(6) K) plasma in the wind of the O supergiant zeta Pup and to explore changes in the 18 yr between two sets of observations of this star. We fit two models - one empirical and one wind-shock-based - to the S XV, Si XIII, and Mg XI line complexes and show that an origin in the wind flow, above r approximate to 1.5 R*, …
Erratum: Chandra Grating Spectroscopy Of Embedded Wind Shock X-Ray Emission From O Stars Shows Low Plasma Temperatures And Significant Wind Absorption, David H. Cohen, Winter Parts, Graham M. Doskoch, Jiaming Wang, Veronique Petit, Maurice A. Leutenegger, Marc Gagné
Erratum: Chandra Grating Spectroscopy Of Embedded Wind Shock X-Ray Emission From O Stars Shows Low Plasma Temperatures And Significant Wind Absorption, David H. Cohen, Winter Parts, Graham M. Doskoch, Jiaming Wang, Veronique Petit, Maurice A. Leutenegger, Marc Gagné
Earth & Space Sciences Faculty Publications
This is an erratum to the paper ‘ Chandra grating spectroscopy of embedded wind shock X-ray emission from O stars shows low plasma temperatures and significant wind absorption’ (2021, MNRAS, 503, 715). We present here a modest correction to the o v erall scaling of the differential emission measures (DEMs) of six O stars originally presented in Cohen et al. ( 2021 ). While working on a follow-up paper, we realized that we had incorrectly converted the bvapec spectral emission model’s normalization parameters (proportional to the emission measure per temperature bin size) to the emission measure per decade Kelvin shown …
Chandra Revisits Wr 48a: Testing Colliding Wind Models In Massive Binaries, Svetozar A. Zhekov, Marc Gagné, Stephen L. Skinner
Chandra Revisits Wr 48a: Testing Colliding Wind Models In Massive Binaries, Svetozar A. Zhekov, Marc Gagné, Stephen L. Skinner
Earth & Space Sciences Faculty Publications
We present results of new Chandra High-Energy Transmission Grating (HETG) observations (2019 November-December) of the massive Wolf-Rayet binary WR 48a. Analysis of these high-quality data showed that the spectral lines in this massive binary are broadened (full width at half-maximum, FWHM = 1400 km s(-1)) and marginally blueshifted (similar to-100 km s(-1)). A direct modelling of these high-resolution spectra in the framework of the standard colliding stellar wind (CSW) picture provided a very good correspondence between the shape of the theoretical and observed spectra. Also, the theoretical line profiles are in most cases an acceptable representation of the observed ones. …
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, Sushma Kurapati, Poonam Chandra, Gregg Wade, David H. Cohen, Alexandre David-Uraz, Marc Gagné, Jason Grunhut, Mary E. Oksala, Veronique Petit, Matt Shultz, Jon Sundqvist, Richard H. D. Townsend, Asif Ud-Doula
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, Sushma Kurapati, Poonam Chandra, Gregg Wade, David H. Cohen, Alexandre David-Uraz, Marc Gagné, Jason Grunhut, Mary E. Oksala, Veronique Petit, Matt Shultz, Jon Sundqvist, Richard H. D. Townsend, Asif Ud-Doula
Earth & Space Sciences Faculty Publications
We conducted a survey of seven magnetic O-type stars and eleven B-type stars with masses above 8 M using the Very Large Array in the 1, 3 and 13 cm bands. The survey resulted in a detection of two O- and two B-type stars. While the detected O-type stars – HD 37742 and HD 47129 – are in binary systems, the detected B-type stars, HD 156424 and ALS 9522, are not known to be in binaries. All four stars were detected at 3 cm, whereas three were detected at 1 cm and only one star was detected at 13 cm. …
On The Redshift Distribution And Physical Properties Of Act-Selected Dsfgs, T. Su, T. A. Marriage, V. Asboth, A. J. Baker, J. R. Bond, D. Crichton, M. J. Devlin, R. Dünner, D. Farrah, D. T. Frayer, M. B. Gralla, K. Hall, M. Halpern, A. I. Harris, M. Hilton, A. D. Hincks, J. P. Hughes, M. D. Niemack, L. A. Page, B. Partridge, J. Rivera, D. Scott, J. L. Sievers, Robert J. Thornton, M. P. Viero, L. Wang, E. J. Wollack, M. Zemcov
On The Redshift Distribution And Physical Properties Of Act-Selected Dsfgs, T. Su, T. A. Marriage, V. Asboth, A. J. Baker, J. R. Bond, D. Crichton, M. J. Devlin, R. Dünner, D. Farrah, D. T. Frayer, M. B. Gralla, K. Hall, M. Halpern, A. I. Harris, M. Hilton, A. D. Hincks, J. P. Hughes, M. D. Niemack, L. A. Page, B. Partridge, J. Rivera, D. Scott, J. L. Sievers, Robert J. Thornton, M. P. Viero, L. Wang, E. J. Wollack, M. Zemcov
Physics & Engineering Faculty Publications
No abstract provided.
X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, D. H. Cohen, G. A. Wade, Y. Naze, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, Marc Gagne
X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, D. H. Cohen, G. A. Wade, Y. Naze, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, Marc Gagne
Earth & Space Sciences Faculty Publications
No abstract provided.
A Chandra Grating Observation Of The Dusty Wolf-Rayet Star Wr 48a, Svetozar A. Zhekov, Marc Gagne, Stephen L. Skinner
A Chandra Grating Observation Of The Dusty Wolf-Rayet Star Wr 48a, Svetozar A. Zhekov, Marc Gagne, Stephen L. Skinner
Earth & Space Sciences Faculty Publications
No abstract provided.
X-Rays From Magnetic Massive Ob Stars, V. Petit, D. H. Cohen, Y. Naze´, Marc Gagne, R. H.D. Townsend, M. A. Leutenegger, A. Ud-Doula, S. P. Owocki, G. A. Wade
X-Rays From Magnetic Massive Ob Stars, V. Petit, D. H. Cohen, Y. Naze´, Marc Gagne, R. H.D. Townsend, M. A. Leutenegger, A. Ud-Doula, S. P. Owocki, G. A. Wade
Earth & Space Sciences Faculty Publications
No abstract provided.
A Multiwavelength View On The Dusty Wolf-Rayet Star Wr 48a, Svetozar A. Zhekov, Toma Tomov, Marcin P. Gawronski, Leonid N. Georgiev, Jura Borissova, Radostin Kurtev, Marc Gagne, Marcin Hajduk
A Multiwavelength View On The Dusty Wolf-Rayet Star Wr 48a, Svetozar A. Zhekov, Toma Tomov, Marcin P. Gawronski, Leonid N. Georgiev, Jura Borissova, Radostin Kurtev, Marc Gagne, Marcin Hajduk
Earth & Space Sciences Faculty Publications
No abstract provided.
An X-Rays Survey Of The Young Stellar Population Of The Lynds 1641 And Iota Orionis Regions, I. Pillitteri, S. J. Wolk, S. T. Megeath, L. Allen, J. Bally, Marc Gagné, R. A. Gutermuth, L. Hartman, G. Micela, P. Myers, J. M. Oliveira, S. Sciortino, F. Walter, L. Rebull, J. Stauffer
An X-Rays Survey Of The Young Stellar Population Of The Lynds 1641 And Iota Orionis Regions, I. Pillitteri, S. J. Wolk, S. T. Megeath, L. Allen, J. Bally, Marc Gagné, R. A. Gutermuth, L. Hartman, G. Micela, P. Myers, J. M. Oliveira, S. Sciortino, F. Walter, L. Rebull, J. Stauffer
Earth & Space Sciences Faculty Publications
We present an XMM-Newton survey of the part of Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star Orionis. In addition to proprietary data, we used archival XMM data of the Orion Nebula Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud. We have detected 1060 X-ray sources in L1641 and Ori region. About 94% of the sources …
Abrupt Longitudinal Magnetic Field Changes And Ultraviolet Emissions Accompanying Solar Flares, B. M. Johnstone, G. J.D. Petrie, Jeffrey J. Sudol
Abrupt Longitudinal Magnetic Field Changes And Ultraviolet Emissions Accompanying Solar Flares, B. M. Johnstone, G. J.D. Petrie, Jeffrey J. Sudol
Physics & Engineering Faculty Publications
No abstract provided.
High-Mass, Four-Planet Configurations For Hr 8799: Constraining The Orbital Inclination And Age Of The System, Jeffrey J. Sudol, Nader Haghighipour
High-Mass, Four-Planet Configurations For Hr 8799: Constraining The Orbital Inclination And Age Of The System, Jeffrey J. Sudol, Nader Haghighipour
Physics & Engineering Faculty Publications
No abstract provided.
Abrupt Longitudinal Magnetic Field Changes In Flaring Active Regions, G. J.D. Petrie, Jeffrey J. Sudol
Abrupt Longitudinal Magnetic Field Changes In Flaring Active Regions, G. J.D. Petrie, Jeffrey J. Sudol
Physics & Engineering Faculty Publications
No abstract provided.
Abundance Analysis Of The Extremely Fast Onemg Novae V838 Herculis And V4160 Sagittarii, G J. Schwarz, S N. Shore, S Starrfield, K M. Vanlandingham
Abundance Analysis Of The Extremely Fast Onemg Novae V838 Herculis And V4160 Sagittarii, G J. Schwarz, S N. Shore, S Starrfield, K M. Vanlandingham
Earth & Space Sciences Faculty Publications
V838 Her and V4160 Sgr were two of the fastest classical novae ever observed, exhibiting light curve declines of 2 mag in less than 2 days. Both novae also showed strong neon emission lines, indicative of an outburst occurring on an oxygen-neon-magnesium white dwarf. Being the brighter of the two, V838 Her has an extensive set of X-ray to radio observations obtained during its first year after outburst. V4160 Sgr has a more modest set of ultraviolet and optical spectra, which show it to be similar to V838 Her, not just in its light curve evolution but also in its …
Longitudinal Magnetic Field Changes Accompanying Solar Flares, Jeffrey J. Sudol, J. W. Harvey
Longitudinal Magnetic Field Changes Accompanying Solar Flares, Jeffrey J. Sudol, J. W. Harvey
Physics & Engineering Faculty Publications
No abstract provided.
An Observational Test Of The Spherical Model Atmospheres For The M Class Giants: The Case Of Δ2 Lyrae, Jeffrey J. Sudol, J. A. Benson, H. M. Dyck, M. Scholz
An Observational Test Of The Spherical Model Atmospheres For The M Class Giants: The Case Of Δ2 Lyrae, Jeffrey J. Sudol, J. A. Benson, H. M. Dyck, M. Scholz
Physics & Engineering Faculty Publications
No abstract provided.
Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich
Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich
Physics & Engineering Faculty Publications
No abstract provided.
Astrophysical Quantities Of Cepheid Variables Measured With The Navy Prototype Optical Interferometer, Tyler E. Nordgren, J. T. Armstrong, M. E. Germain, R. B. Hindsley, Arsen R. Hajian, Jeffrey J. Sudol, C. A. Hummel
Astrophysical Quantities Of Cepheid Variables Measured With The Navy Prototype Optical Interferometer, Tyler E. Nordgren, J. T. Armstrong, M. E. Germain, R. B. Hindsley, Arsen R. Hajian, Jeffrey J. Sudol, C. A. Hummel
Physics & Engineering Faculty Publications
No abstract provided.
Stellar Angular Diameters Of Late-Type Giants And Supergiants Measured With The Navy Prototype Optical Interferometer, Tyler E. Nordgren, M. E. Germain, J. A. Benson, D. Mozurkewich, Jeffrey J. Sudol, N. M. Elias Ii, Arsen R. Hajian, N. M. White, D. J. Hutter, K. J. Johnston, F. S. Gauss, J. T. Armstrong, T. A. Pauls, L. J. Rickard
Stellar Angular Diameters Of Late-Type Giants And Supergiants Measured With The Navy Prototype Optical Interferometer, Tyler E. Nordgren, M. E. Germain, J. A. Benson, D. Mozurkewich, Jeffrey J. Sudol, N. M. Elias Ii, Arsen R. Hajian, N. M. White, D. J. Hutter, K. J. Johnston, F. S. Gauss, J. T. Armstrong, T. A. Pauls, L. J. Rickard
Physics & Engineering Faculty Publications
No abstract provided.
Mid-Infrared Visibility Measurements Of Evolved Stars, Jeffrey J. Sudol, H. M. Dyck, R. E. Stencel, D. I. Klebe, M. J. Creech-Eakman
Mid-Infrared Visibility Measurements Of Evolved Stars, Jeffrey J. Sudol, H. M. Dyck, R. E. Stencel, D. I. Klebe, M. J. Creech-Eakman
Physics & Engineering Faculty Publications
No abstract provided.