5,193 research outputs found
Adapting to Climate Change: A Call for Federal Leadership
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
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 TK, log , 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 TK,
log , plus an accretion belt with TK covering 27% of
the white dwarf surface with V 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
Cow-Calf Performance from Common, Coastal, and Tifton 85 Bermudagrass When Grazed at Three Stocking Rates
Last updated: 6/12/200
TESS Data Release Notes: Sector 18 DR25
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
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
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
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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