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458 results on '"GUENTHER, B."'

2. HR 5907: Discovery of the most rapidly rotating magnetic B-type star by the MiMeS Collaboration

Author

Grunhut, J. H., Rivinius, Th., Wade, G. A., Townsend, R. H. D., Marcolino, W. L. F., Bohlender, D. A., Szeifert, Th., Petit, V., Matthews, J. M., Rowe, J. F., Moffat, A. F. J., Kallinger, T., Kuschnig, R., Guenther, B. D., Rucinski, S. M., Sasselov, D., Weiss, W. W., and Collaboration, the MiMeS

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We report the discovery and analysis of a very strong magnetic field in the rapidly rotating early B-type star HR 5907, based on observations obtained as part of the Magnetism in Massive Stars (MiMeS) project. We infer a rotation period of 0.508276 +0.000015/-0.000012 d from photometric and H{\alpha} EW measurements, making this the shortest period, non-degenerate, magnetic massive star known to date. From the comparison of IUE UV and optical spectroscopy with LTE BRUCE/KYLIE models we find a solid-angle integrated, uniform black-body temperature of 17 000 \pm 1000 K, a projected rotational velocity of 290 \pm 10 km/s, an equatorial radius of 3.1 \pm 0.2 R_sun, a stellar mass of 5.5 \pm 0.5 M_sun, and an inclination angle of the rotation axis to our line-of-sight of 70 \pm 10\circ. Our measurements of the longitudinal magnetic field, which vary between -500 and -2000 G, phase coherently with the rotation period and imply a surface dipole field strength of \sim15.7 kG. On the other hand, from fits to mean Least-Squares Deconvolved Stokes V line profiles we infer a dipole field strength of \sim10.4 kG. This disagreement may result from a magnetic configuration more complex than our model, and/or from the non-uniform helium surface abundance distribution. In either case we obtain a magnetic obliquity nearly aligned with the rotation axis ({\beta} = 7+2/-1\circ). Our optical spectroscopy also shows weak variability in carbon, silicon and nitrogen lines. The emission variability in hydrogen Balmer and Paschen lines indicates the presence of a dense, highly structured magnetosphere, interpreted as a centrifugally supported, magnetically confined circumstellar disk., Comment: 19 pages, 17 figures (highly compressed), 3 tables, accepted for publication by MNRAS

Published
2011
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17. Mitochondrial phylogeography of the European wild boar: the effect of climate on genetic diversity and spatial lineage sorting across Europe

Author

Vilaça, Sibelle T., Biosa, Daniela, Zachos, Frank, Iacolina, Laura, Kirschning, Julia, Alves, Paulo C., Paule, Ladislav, Gortazar, Christian, Mamuris, Zizzis, Jędrzejewska, Bogumiła, Borowik, Tomasz, Sidorovich, Vadim E., Kusak, Josip, Costa, Stefano, Schley, Laurent, Hartl, Günther B., Apollonio, Marco, Bertorelle, Giorgio, and Scandura, Massimo

Published
2014
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39. Satellite Ozone Measurements

Author

Krueger, A. J., Guenther, B., Fleig, A. J., Heath, D. F., Hilsenrath, E., McPeters, R., and Prabhakara, C.

Published
1980

49. Prelaunch algorithm and data format for the Level 1 calibration products for the EOS-AM1 Moderate Resolution Imaging Spectroradiometer (MODIS)

Author

Guenther, B., Godden, Gerald D., Xiong, Xiaoxiong, Knight, Edward J., Qiu, Shi-Yue, Montgomery, Harry, Hopkins, M.M., Khayat, Mohammad G., and Hao, Zhidong

Subjects
United States. Goddard Space Flight Center. Earth Observing System -- Buildings and facilities, Spectroradiometer -- Information management, Artificial satellites in remote sensing -- Equipment and supplies, Calibration -- Equipment and supplies, Business, Earth sciences, Electronics and electrical industries
Abstract

The Moderate Resolution Imaging Spectroradiometer (MODIS) radiometric calibration product (Level 1B) is described for the thermal emissive and reflective solar bands. A band-integrated radiance is produced for all measurements. A reflectance factor product is also produced for the reflected solar band measurements. Specific sensor design characteristics are identified to assist in understanding how the calibration algorithm software product is designed. The product file format is summarized, and the location for the current file format is provided.

Published
1998

50. High Resolution Sub-Millimeter Spectroscopy Using Mode-Locked Laser Driven Electro-Optic Antennas

Author

Goyette, T. M., Guo, W., De Lucia, F. C., Brown, E. R., McIntosh, K. A., Juvan, K., Swartz, J. C., Everitt, H. O., Guenther, B. D., Goldanskii, Vitalii I., editor, Schäfer, Fritz Peter, editor, Toennies, J. Peter, editor, Lotsch, Helmut K. V., editor, Barbara, Paul F., editor, Fujimoto, James G., editor, Knox, Wayne H., editor, and Zinth, Wolfgang, editor

Published
1996
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