Wind Variability in BZ Camelopardalis

(Shortened) Sequences of spectra of the nova-like cataclysmic variable (CV) BZ Cam were acquired on 9 nights in 2005-2006 in order to study the time development of episodes of wind activity known to occur frequently in this star. We confirm past results that the P-Cygni absorption components of the lines mostly evolve from a higher expansion velocity to lower velocity as an episode progresses. We also commonly find blueshifted emission components in the Halpha line profile, whose velocities and durations strongly suggest that they are also due to the wind. We suggest that the progression from larger to smaller expansion velocities is due the higher velocity portions of a wind concentration moving beyond the edge of the continuum light of the disk first, leaving a net redward shift of the remaining absorption profile. We also derive a new orbital ephemeris for BZ Cam, using the radial velocity of the core of the HeI 5876AA line, finding P = 0.15353(4). Using this period the wind episodes in BZ Cam are found to be concentrated near inferior conjuction of the emission line source. This result confirms that the winds in nova-like CVs are often phase dependent, in spite of the puzzling implication that such winds lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an initial boost by acting on gas that has been lifted above the disk by the interaction of the accretion stream with the disk, thereby imposing flickering time scales onto the wind events, as well as leading to an orbital modulation of the wind due to the non-axisymmetric nature of the stream/disk interaction.Comment: The Astronomical Journal, in pres

The Long-Period Orbit of the Dwarf Nova V630 Cassiopaeia

We present extensive spectroscopy and photometry of the dwarf nova V630 Cassiopeiae. A late-type (K4-5) absorption spectrum is easily detectable, from which we derive the orbital parameters. We find a spectroscopic period of P=2.56387 +/- (4 times 10^{-5}) days and a semiamplitude of K_2=132.9 +/- 4.0 km/s. The resulting mass function, which is a firm lower limit on the mass of the white dwarf, is then f(M)=0.624 +/- 0.056 solar masses. The secondary star is a ``stripped giant'', and using relations between the core mass and the luminosity and the core mass and the radius we derive a lower limit of M_2 > 0.165 solar masses for the secondary star. The rotational velocity of the secondary star is not resolved in our spectra and we place a limit of V_rot*sin(i) < 40 km/s. The long-term light curve shows variations of up to 0.4 mag on short (1-5 days) time scales, and variations of 0.2-0.4 mag on longer (3-9 months) time scales. In spite of these variations, the ellipsoidal light curve of the secondary star is easily seen when the data are folded on the spectroscopic ephemeris. Ellipsoidal models fit to the mean light curve give an inclination in the range 66.96 < i < 78.08 degrees (90 per cent confidence). This inclination range, and the requirement that M_2 > 0.165 solar masses and V_rot*sin(i) < 40 km/s yields a white dwarf mass of M_1=0.977^{+0.168}_{-0.098} solar masses and a secondary star mass of M_2=0.172^{+0.029}_{-0.012} solar masses (90 per cent confidence limits). Our findings confirm the suggestion of Warner (1994), namely that V630 Cas is rare example of a dwarf nova with a long orbital period.Comment: 8 pages, 9 figures, to appear in MNRA

Community-Based Interventions to Decrease Obesity and Tobacco Exposure and Reduce Health Care Costs: Outcome Estimates From Communities Putting Prevention to Work for 2010–2020

INTRODUCTION: In 2010, the Centers for Disease Control and Prevention (CDC) launched Communities Putting Prevention to Work (CPPW), a $485 million program to reduce obesity, tobacco use, and exposure to secondhand smoke. CPPW awardees implemented evidence-based policy, systems, and environmental changes to sustain reductions in chronic disease risk factors. This article describes short-term and potential long-term benefits of the CPPW investment. METHODS: We used a mixed-methods approach to estimate population reach and to simulate the effects of completed CPPW interventions through 2020. Each awardee developed a community action plan. We linked plan objectives to a common set of interventions across awardees and estimated population reach as an early indicator of impact. We used the Prevention Impacts Simulation Model (PRISM), a systems dynamics model of cardiovascular disease prevention, to simulate premature deaths, health care costs, and productivity losses averted from 2010 through 2020 attributable to CPPW. RESULTS: Awardees completed 73$2.4 billion (in 2010 dollars) in discounted direct medical costs, and $9.5 billion (in 2010 dollars) in discounted lifetime and annual productivity losses through 2020. CONCLUSION: PRISM results suggest that large investments in community preventive interventions, if sustained, could yield cost savings many times greater than the original investment over 10 to 20 years and avert 14,000 premature deaths

Post-Common-Envelope Binary Stars and the Precataclysmic Binary PG 1114+187

We present orbit-resolved spectroscopy and orbit-sampled photometry of the binary system PG 1114+187. Both photometry and radial velocity studies reveal a period P = 1.75992 days, which is taken to be the orbital period of the binary. Strong modulation of emission-line strength with the same period is also present. A preliminary mass ratio, M2/M1 ‰ˆ 0.7, is found from primary- and secondary-star radial velocity amplitudes. No evidence is seen for either an accretion disk or mass transfer, leading to the conclusion that PG 1114+187 is not a cataclysmic variable (CV) but is in a pre-CV state, before the initiation of mass transfer. The short orbital period also leads to the conclusion that the system passed through a common-envelope phase at some time in the past. The current list of known post-common-envelope and precataclysmic binary stars is also reviewed and the general properties of this class of star are discussed

MEASUREMENTS OF CYANIDE AND OXIDE BAND STRENGTHS IN COOL STARTS WITH A RAPID SCANNER

Author Institution: Astronomy Department, Indiana UniversityObservations of molecular bands in the stars $\alpha$ Ori and 19 Psc have been made with the rapid scanner on the one meter optical telescope at Indiana University’s Goethe Link Observatory. The wavelength range 3500-6000 \AA was observed at 20 \AA resolution with the data digitized each 4 \AA, while the range 6000-12000 \AA was covered at 40 \AA resolution, digitized at 6.6 \AA intervals. The spectrometer grating is driven by a stepping motor which is programmed to repeatedly scan the wavelength range of interest at a speed of 667 \AA/sec. The amplified photomultiplier signal is fed to a 1024-channel digital signal averager which is cycled at the grating repetition rate. Forward and reverse scans are accumulated separately in memory so that the accuracy of the scans can be judged from a comparison of the forward and reverse positions. The rapid scan spectrometer is capable of greater accuracy than a conventional single scan instrument because low frequency noise components due to changes in the night sky transparency are avoided. In addition, the observing time can easily be extended to any convenient length necessary for the desired accuracy without laborous averaging of scans. The observed flux errors for the stars 19 Psc and $\alpha$ Ori are three and one percent respectively. The scans of the star 19 Psc show strong bands of the $\Delta v$ = 0, 1, 2, 3 sequences of the $A^{2}$11 - $X^{2}\Sigma$ system of the CN radical from 6000-12000 \AA, and $C_{2}$ Swan bands from 4000-6000 \AA. At wavelengths shorter than 4000 \AA, the light flux from 19 Psc is too small to measure with the accuracy cited above. The star $\alpha$ Ori shows much weaker bands of the red system of CN, and also weak bands of the singlet and triplet electronic systems of TiO throughout this wavelength region. These scans compare favorably with previous work on the same bands in these stars by R. Wing (1967, Ph.D. thesis, U. of Calif., Berkeley) using 27 frequency points between 7500-11000 \AA. The principal advantage of the present work is the detail observed in the structure of these CN and TiO bands at the more than 1500 wavelength points used by the authors. A second advantage is that Wing’s observations are extended from 7500-4000 \AA with photoelectric accuracy at comparable spectral resolution. Methods for calibrating the results and removing the terrestrial $O_{2}$ and $H_{2} O$ bands from the scans at these wavelengths are discussed

Light Curve of CR Bootis 1990-2012 From the Indiana Long-Term Monitoring Program

Two telescopes are used at the Morgan-Monroe Observatory of Indiana University for autonomous long-term photometric monitoring of stellar sources, mostly cataclysmic variable stars. The instrumentation is designed and implemented to be appropriate for multiyear automated monitoring. The capabilities and limitations of the equipment are described, along with accounts of the software, the reduction procedures, the motivations for the scientific programs, and the execution of the observing campaigns. Data on the AM CVn-type cataclysmic variable CR Boo are presented and discussed as an example of the kinds of light curves generated at this facility. The He-rich disk in CR Boo has SU UMa-type outburst behavior, with both superoutbursts and what appear to be dwarf nova outbursts. However, the light curve is quite irregular and displays a wide variety of unusual features such as switching among several superoutburst recurrence intervals, and having intervals of dwarf nova-like outbursts that seem to come and go. We discuss the likelihood that deterministic chaos is responsible for these irregularities. © 2013. The Astronomical Society of the Pacific. All rights reserved