Výsledky vyhledávání - "Douglas O'neal"

Recurrent star-spot activity and differential rotation in KIC 11560447

Autor: Emre Işık, Douglas O'Neal, M. Yılmaz, Gaitee A. J. Hussain, I. Özavcı, Hakan Volkan Şenavci, Selim O. Selam

Publikováno v: Monthly Notices of the Royal Astronomical Society. 474:5534-5548

We present a detailed analysis of surface inhomogeneities on the K1-type sub-giant component of the rapidly rotating eclipsing binary KIC 11560447, using high-precision Kepler light curves spanning nearly four years, corresponding to about 2800 orbit

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8c269a3defb918a624912e032a921159
https://doi.org/10.1093/mnras/stx3053

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Starspot activity and differential rotation in KIC 11560447

Autor: Hakan Volkan Şenavci, Emre Işık, I. Özavcı, Gaitee A. J. Hussain, Selim O. Selam, Douglas O'Neal, M. Yılmaz

Publikováno v: Proceedings of the International Astronomical Union. 13:235-236

Using high-precision photometry from the \textit{Kepler} mission, we investigate patterns of spot activity on the K1-type subgiant component of KIC 11560447, a short-period late-type eclipsing binary. We tested the validity of maximum entropy reconst

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8a400056078051b55766317b48bad906
https://doi.org/10.1017/s174392131800145x

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On the Use of Line Depth Ratios to Measure Starspot Properties on Magnetically Active Stars

Autor: Douglas O'Neal

Publikováno v: The Astrophysical Journal. 645:659-663

Photometric and spectroscopic techniques have proven to be effective ways to measure the properties of dark, cool starspots on magnetically active stars. Recently, a technique was introduced using atomic line depth ratios (LDRs) to measure starspot p

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::810b6d53e6f567debb2e2e2f8f0e52c4
https://doi.org/10.1086/504318

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Further Results of TiO-Band Observations of Starspots

Autor: James E. Neff, Manfred Cuntz, Douglas O'Neal, Steven H. Saar

Publikováno v: The Astronomical Journal. 128:1802-1811

We present measurements of starspot parameters (temperature and filling factor) on five highly active stars, using absorption bands of TiO, from observations made between 1998 March and 2001 December. We determined starspot parameters by fitting TiO

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::ea6f5fd1b4ca642b8cd416e71e63bdba
https://doi.org/10.1086/423438

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Hydroxyl 1.563 Micron Absorption from Starspots on Active Stars

Autor: Douglas O’Neal, Steven H. Saar, Jonathan K. Mines, James E. Neff

Publikováno v: The Astronomical Journal. 122:1954-1964

We present results from a study of starspots on active stars using a pair of vibrational-rotational absorption lines of the OH molecule near 1.563 μm. We detect excess OH absorption due to dark, cool starspots on several active stars of the RS CVn a

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::d45606b8e23a14543172ef3c02110528
https://doi.org/10.1086/323093

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A search for the cause of cyclical wind variability in O stars

Autor: James E. Neff, D. A. Bohlender, Y. Jiang, Karl D. Gordon, H.F. Henrichs, Karen S. Bjorkman, I. Kolka, J. Telting, Douglas O'Neal, Nancy D. Morrison, J.A. de Jong, B. Scheers, Lex Kaper, Gary J Hill, J.S. Nichols, H. Cao

Publikováno v: Astronomy and Astrophysics
Astronomy and Astrophysics, 368, 601-621. EDP Sciences
Astronomy & Astrophysics, 368, 601-621. EDP Sciences

We present the results of an extensive observing campaign on the O7.5 III star Persei. The UV obser- vations were obtained with the International Ultraviolet Explorer. Per was monitored continuously in October 1994 during 10 days at ultraviolet and v

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::eb9bd8dd584a9bb5f81b0a2850b0c263
https://doi.org/10.1051/0004-6361:20000570

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Measurements of Starspot Parameters on Active Stars using Molecular Bands in Echelle Spectra

Autor: James E. Neff, Douglas O'Neal, Steven H. Saar

Publikováno v: The Astrophysical Journal. 507:919-937

We present results from a study of starspot areas (fS) and temperatures (TS), primarily on active, single-lined spectroscopic binaries, determined using molecular absorption bands. Expanding upon our previous studies, we have analyzed multiorder eche

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::9609d261f8c8a75e9b5f641d842d49de
https://doi.org/10.1086/306340

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Radio Emission from Young Stellar Objects near LkHα 101

Autor: Douglas O'Neal, Peter Stine

Publikováno v: The Astronomical Journal. 116:890-894

We present results of a VLA 3.6 cm B-configuration study of a region around the Herbig Be star LkHα 101. We detect 16 sources down to 5 σ (rms) thresholds of 0.25 mJy. Most of the sources are thought to be young stellar objects associated with the

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::dcb7c1b0e2967f6cb1f83f3e4d8d1cf1
https://doi.org/10.1086/300473

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Absolute Measurements of Starspot Area and Temperature

Autor: James E. Neff, Steven H. Saar, Douglas O'Neal

Publikováno v: International Astronomical Union Colloquium. 137:193-195

Photometric and spectroscopic variability of late-type stars frequently has been interpreted as evidence of magnetic activity. The standard picture of stellar activity – inherited from solar observations – includes cool, dark “spots” in the p

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::cb8d96e7a0313bfb42e4a679876cdfe6
https://doi.org/10.1017/s0252921100017760

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