355 research outputs found
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Transracial Adoptees: Searching for Birth Families and Developing Identities
White Dwarfs in Cataclysmic Variables: An Update
In this review, we summarize what is currently known about the surface temperatures of accreting white dwarfs in nonmagnetic and magnetic cataclysmic variables (CVs) based upon synthetic spectral analyses of far ultraviolet data. We focus only on white dwarf surface temperatures, since in the area of chemical abundances, rotation rates, WD masses and accretion rates, relatively little has changed since our last review, pending the results of a large HST GO programinvolving 48 CVs of different CV types. The surface temperature of the white dwarf in SS Cygni is re-examined in the light of its revised distance. We also discuss new HST spectra of the recurrent nova T Pyxidis as it transitioned into quiescence following its April 2011 nova outburst
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Positive and Negative Aspects of Transracial Adoption: An Exploratory Study from Korean Transracial Adoptees\u27 Perspectives
This purpose of this study was to learn how transracial adoptees (TRAs) feel about transracial adoption. Ninety-five adult Korean-born adoptees (73 female and 22 male) responded to open-ended questions about the positive and negative aspects of being transracially adopted. More adoptees felt generally positive than negative, but most had mixed feelings. Positive aspects most often cited included: being a part of two cultures; developing personal awareness, open-mindedness, and deeper understandings; and being unique. Common negative aspects included isolation from one’s adoptive and birth families and cultures; the burden of dealing with others’ assumptions and questions about transracial adoption; and identity fragmentation
V3885 Sagittarius: a Comparison with a Range of Standard Model Accretion Disks
A analysis of standard model accretion disk synthetic
spectrum fits to combined and STIS spectra of V3885 Sagittarius, on an
absolute flux basis, selects a model that accurately represents the observed
SED. Calculation of the synthetic spectrum requires the following system
parameters. The cataclysmic variable secondary star period-mass relation
calibrated by Knigge in 2007 sets the secondary component mass. A mean white
dwarf (WD) mass from the same study, that is consistent with an
observationally-determined mass ratio, sets the adopted WD mass of
, and the WD radius follows from standard theoretical models. The
adopted inclination, i=65{\arcdeg}, is a literature consensus, and is
subsequently supported by analysis. The mass transfer rate
is the remaining parameter to set the accretion disk profile, and
the parallax constrains that parameter to
by a comparison
with observed spectra. The fit to the observed spectra adopts the contribution
of a K WD. The model thus provides realistic constraints on
and for a large system above the period gap.Comment: 41 pages, 7 figures, 9 tables. Astrophysical Journal (accepted
The boundary layer of VW Hyi in quiescence
In this letter, we suggest that the missing boundary layer luminosity of
dwarf novae in quiescence is released mainly in the ultraviolet (UV) as the
second component commonly identified in the far ultraviolet (FUV) as the
"accretion belt".
We present the well-studied SU UMa-type system VW Hyi in detail as a
prototype for such a scenario. We consider detailed multiwavelength
observations and in particular the recent FUSE observations of VW Hyi which
confirm the presence of a second component (the "accretion belt") in the FUV
spectrum of VW Hyi in quiescence. The temperature (50,000K) and rotational
velocity (> 3,000km/s) of this second FUV component are entirely consistent
with the optically thick region (tau = 1) located just at the outer edge of
optically thin boundary layer in the simulations of Popham (1999).
This second component contributes 20% of the FUV flux, therefore implying a
boundary layer luminosity: , while the theory (Klu\'zniak 1987) predicts, for the
rotation rate of VW Hyi's WD, . The remaining
accretion energy () is apparently advected into the star as
expected for optically thin advection dominated boundary layers. This scenario
is consistent with the recent simultaneous X-ray and UV observations of VW Hyi
by (Pandel, C\'ordova & Howell 2003), from which we deduced here that the alpha
viscosity parameter in the boundary layer region must be as small as .Comment: 4 page
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