5,193 research outputs found

    Adapting to Climate Change: A Call for Federal Leadership

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    Recommends creating a strategic planning initiative to set goals, objectives, and priorities; a national climate service to provide information on climate change impacts and adaptation options; and an adaptation research program. Includes case summaries

    Composite Accretion Disk and White Dwarf Photosphere Analyses of the FUSE and HST Observations of EY Cygni

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    We explore the origin of FUSE and HST STIS far UV spectra of the dwarf nova, EY Cyg, during its quiescence using \emph{combined} high gravity photosphere and accretion disk models as well as model accretion belts. The best-fitting single temperature white dwarf model to the FUSE plus HST STIS spectrum of EY Cygni has Teff=24,000_{eff} = 24,000K, log g=9.0g = 9.0, with an Si abundance of 0.1 x solar and C abundance of 0.2 x solar but the distance is only 301 pc. The best-fitting composite model consists of white dwarf with Teff=22,000_{eff} = 22,000K, log g=9g = 9, plus an accretion belt with Tbelt=36,000_{belt} = 36,000K covering 27% of the white dwarf surface with Vbeltsini=2000_{belt} sin i = 2000 km/s. The accretion belt contributes 63% of the FUV light and the cooler white dwarf latitudes contribute 37%. This fit yields a distance of 351 pc which is within 100 pc of our adopted distance of 450 pc. EY Cyg has very weak C {\sc iv} emission and very strong N {\sc v} emission, which is atypical of the majority of dwarf novae in quiescence. We also conducted a morphological study of the surroundings of EY Cyg using direct imaging in narrow nebular filters from ground-based telescopes. We report the possible detection of nebular material^M associated with EY Cygni. Possible origins of the apparently large N {\scv}/C {\sc iv} emission ratio are discussed in the context of nova explosions, contamination of the secondary star and accretion of nova abundance-enriched matter back to the white dwarf via the accretion disk or as a descendant of a precursor binary that survived thermal timescale mass transfer. The scenario involving pollution of the secondary by past novae may be supported by the possible presence of a nova remnant-like nebula around EY Cyg.Comment: To appear in AJ, Oct. 2004. 5 figures, including 2 color ones (2D pictures

    TESS Data Release Notes: Sector 18 DR25

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    This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 18 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

    TESS Data Release Notes: Sector 17, DR24

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    This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 17 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

    TESS Data Release Notes: Sector 20, DR27

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    This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 20 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

    TESS Data Release Notes: Sector 16, DR22

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    This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 16 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics
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