Results 11 to 20 of about 169 (167)
Are DY Persei Stars Cooler Cousins of R Coronae Borealis Stars? [PDF]
The Astrophysical Journal, 2018 Abstract In this paper we present, for the first time, the study of low resolution H- and K-band spectra of 7 DY Per type and suspect stars, as well as DY Persei itself. We also observed H- and K-band spectra of 3 R Coronae Borealis (RCB) stars, 1 hydrogen-deficient carbon (HdC) star, and 14 cool carbon stars, including normal giants as ...
Anirban Bhowmick +3 more
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Classical T Tauri stars: magnetic fields, coronae and star–disc interactions [PDF]
Monthly Notices of the Royal Astronomical Society, 2013 The magnetic fields of young stars set their coronal properties and control their spin evolution via the star-disc interaction and outflows. Using 14 magnetic maps of 10 classical T Tauri stars (CTTSs) we investigate their closed X-ray emitting coronae, their open wind-bearing magnetic fields, and the geometry of magnetospheric accretion flows.
Johnstone, C. P. +4 more
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On X‐Ray Optical Depth in the Coronae of Active Stars [PDF]
The Astrophysical Journal, 2007 Accepted for publication on the Astrophysical ...
TESTA, Paola +3 more
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On Star Coloring of Several Corona Graphs
Journal of Physics: Conference Series, 2021 Abstract Let G be a simple graph with vertex set V(G) and edge set E(G). A vertex coloring of G is called a star coloring of G if any of the paths of 4 order are bicolored. The minimum number of colors required for a star coloring of G is denoted by χs (G). The corona product of simple graphs G of order m and H of order
Jin Cai, Shuangliang Tian, Zhuomo An
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The coronae of main-sequence A stars
The Astronomical Journal, 1993 We have undertaken a deep X-ray imaging survey of single, normal, mid-to-late-A- and early-F-type main-sequence stars using the ROSA T PSPC. Eight of the nine such stars in our fields went undetected at very weak emission levels, with upper limits on the normalized X-ray flux in each case of better than log R(x) below -6.3.
Theodore Simon, Stephen A. Drake
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Structures of Binary Star Coronae [PDF]
Symposium - International Astronomical Union, 2004 Stellar coronae in binary star systems offer both a puzzle and an opportunity. We might expect that large magnetic loop structures on close binaries, such as RS CVn systems and contact binaries, would show evidence for interactions between the stars. While some radio studies support this scenario, there is surprisingly little evidence from EUV and X ...
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Models for R Coronae Borealis Stars [PDF]
International Astronomical Union Colloquium, 1971 If we believe in the spectral analysis of the atmospheres of RCrB stars these objects should have a pure helium envelope slightly enriched in carbon (SEARLE 1961, DANZIGER 1965). However, they cannot be homogeneous helium stars since in that case they should be on the helium main sequence in the Hertzsprung-Russell-diagram, whereas they are found in ...
P. Biermann, R. Kippenhahn
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Revised Surface Abundances of R Coronae Borealis Stars [PDF]
The Astrophysical Journal, 2021 Abstract Surface abundances of 14 (11 majority class and three minority class) R Coronae Borealis stars (RCBs) along with the final-flash object, V4334 Sgr (Sakurai’s object) are revised based on their carbon abundances measured from the observed C2 bands; note that the earlier reported abundances were derived using an assumed carbon ...
Pandey, Gajendra +7 more
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The Corona Australis Star Forming Region
, 2008 22 pages, 8 figures, to appear in the "Handbook of Star Forming Regions", ed. B. Reipurth (ASP Monograph Series)
Neuhaeuser, R., Forbrich, J.
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Winds in R Coronae Borealis Stars [PDF]
The Astrophysical Journal, 2003 14 pages, 4 figures, ApJ in ...
Clayton, Geoffrey C. +2 more
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