Misc. Pub. 99-6

Sausages, one of the oldest forms of processed food, are a means of using and preserving animal trimmings. The hot dog is a specialized sausage. It originated in Germany where it was named “dachshund” sausage because it looked like the popular badger (dachs) hound (hund). The U.S. hot dog originated at the Polo Grounds in New York. Vendors hawked dachshund sausages in buns while a sports cartoonist sketched a barking dachshund nestled warmly in a bun. He labeled the cartoon “hot dog”. Today the hot dog enjoys popularity throughout the world

The enigmatic He-sdB pulsator LS IV−-14∘^\circ116: new insights from the VLT

The intermediate Helium subdwarf B star LS IV$-$14$^\circ$116 is a unique object showing extremely peculiar atmospheric abundances as well as long-period pulsations that cannot be explained in terms of the usual opacity mechanism. One hypothesis invoked was that a strong magnetic field may be responsible. We discredit this possibility on the basis of FORS2 spectro-polarimetry, which allows us to rule out a mean longitudinal magnetic field down to 300 G. Using the same data, we derive the atmospheric parameters for LS IV$-$14$^\circ$116 to be $T_{\rm eff}$ = 35,150$\pm$111 K, $\log{g}$ = 5.88$\pm$0.02 and $\log{N(\rm He)/N(\rm H)}$ = $-$0.62$\pm$0.01. The high surface gravity in particular is at odds with the theory that LS IV$-$14$^\circ$116 has not yet settled onto the Helium Main Sequence, and that the pulsations are excited by an $\epsilon$ mechanism acting on the Helium-burning shells present after the main Helium flash. Archival UVES spectroscopy reveals LS IV$-$14$^\circ$116 to have a radial velocity of 149.1$\pm$2.1 km/s. Running a full kinematic analysis, we find that it is on a retrograde orbit around the Galactic centre, with a Galactic radial velocity component $U$=13.23$\pm$8.28 km/s and a Galactic rotational velocity component $V$=$-$55.56$\pm$22.13 km/s. This implies that LS IV$-$14$^\circ$116 belongs to the halo population, an intriguing discovery.Comment: accepted for publication in A&

Candidate hypervelocity stars of spectral type G and K revisited

Hypervelocity stars (HVS) move so fast that they are unbound to the Galaxy. When they were first discovered in 2005, dynamical ejection from the supermassive black hole (SMBH) in the Galactic Centre (GC) was suggested as their origin. The two dozen HVSs known today are young massive B stars, mostly of 3-4 solar masses. Recently, 20 HVS candidates of low mass were discovered in the Segue G and K dwarf sample, but none of them originates from the GC. We embarked on a kinematic analysis of the Segue HVS candidate sample using the full 6D phase space information based on new proper motion measurements. Their orbital properties can then be derived by tracing back their trajectories in different mass models of our Galaxy. We present the results for 14 candidate HVSs, for which proper motion measurements were possible. Significantly lower proper motions than found in the previous study were derived. Considering three different Galactic mass models we find that all stars are bound to the Galaxy. We confirm that the stars do not originate from the GC. The distribution of their proper motions and radial velocities is consistent with predictions for runaway stars ejected from the Galactic disk by the binary supernova mechanism. However, their kinematics are also consistent with old disk membership. Moreover, most stars have rather low metallicities and strong $\alpha$-element enrichment as typical for thick disk and halo stars, whereas the metallicity of the three most metal-rich stars could possibly indicate that they are runaway stars from the thin disk. One star shows halo kinematics.Comment: A&A letter accepte

Hot subdwarf stars and their connection to thermonuclear supernovae

Hot subdwarf stars (sdO/Bs) are evolved core helium-burning stars with very thin hydrogen envelopes, which can be formed by common envelope ejection. Close sdB binaries with massive white dwarf (WD) companions are potential progenitors of thermonuclear supernovae type Ia (SN Ia). We discovered such a progenitor candidate as well as a candidate for a surviving companion star, which escapes from the Galaxy. More candidates for both types of objects have been found by crossmatching known sdB stars with proper motion and light curve catalogues. The Gaia mission will provide accurate astrometry and light curves of all the stars in our hot subdwarf sample and will allow us to compile a much larger all-sky catalogue of those stars. In this way we expect to find hundreds of progenitor binaries and ejected companions.Comment: Proceedings of the 11th Pacific Rim Conference on Stellar Astrophysics, Hong Kong 2015, Journal of Physics: Conference Series, in pres

The MUCHFUSS photometric campaign

Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which lost almost all of their hydrogen envelopes. This mass loss is often triggered by common envelope interactions with close stellar or even substellar companions. Cool companions like late-type stars or brown dwarfs are detectable via characteristic light curve variations like reflection effects and often also eclipses. To search for such objects we obtained multi-band light curves of 26 close sdO/B binary candidates from the MUCHFUSS project with the BUSCA instrument. We discovered a new eclipsing reflection effect system ($P=0.168938$~d) with a low-mass M dwarf companion ($0.116 M_{\rm \odot}$). Three more reflection effect binaries found in the course of the campaign were already published, two of them are eclipsing systems, in one system only showing the reflection effect but no eclipses the sdB primary is found to be pulsating. Amongst the targets without reflection effect a new long-period sdB pulsator was discovered and irregular light variations were found in two sdO stars. The found light variations allowed us to constrain the fraction of reflection effect binaries and the substellar companion fraction around sdB stars. The minimum fraction of reflection effect systems amongst the close sdB binaries might be greater than 15\% and the fraction of close substellar companions in sdB binaries might be as high as $8.0\%$. This would result in a close substellar companion fraction to sdB stars of about 3\%. This fraction is much higher than the fraction of brown dwarfs around possible progenitor systems, which are solar-type stars with substellar companions around 1 AU, as well as close binary white dwarfs with brown dwarf companions. This might be a hint that common envelope interactions with substellar objects are preferentially followed by a hot subdwarf phase.Comment: accepted for A&

Taking a Day off to Pray: Closing Schools for Religious Observance in Increasingly Diverse Schools

States and public schools across the Nation consistently debate the number of days students must be in attendance, the length of the day, and the configuration of those days to maximize learning opportunities. Establishing the school calendar within each state’s statutory minimum can be challenging as many states still maintain somewhat traditional (albeit antiquated) calendars, which commence the school year around Labor Day and conclude shortly after June begins.1 Public schools are generally in session for 180 school days. Some states have been more creative in their scheduling by reducing the number of days required of student attendance in favor of expanded school days, citing reduced costs. Attempting to schedule 180 school days in the period of late August through early June does not provide schools with much flexibility should they be required to close for exigent circumstances such as inclement weather. Providing students with additional days off for holidays and religious observances only increases the complexity of meeting the required number of school days in a respective state given these calendar constraints

When Speech Is Your Stock in Trade: What Kennedy v. Bremerton School District Reveals about the Future of Employee Speech and Religion Jurisprudence

Coaches play an important role in establishing a nondiscriminatory environment in public-school athletics, both on and off the field. In addition to the duties associated with training a team for athletic competition, coaches, like teachers, are hired to communicate with players and spectators both verbally and demonstratively. Coaches are expected to not only teach sports techniques, but also teach character, leadership, sportsmanship, and other positive character traits. In Kennedy v. Bremerton School District, courts from the district level to the Supreme Court have considered how Coach Joe Kennedy\u27s role as a coach factored into his right to pray on the 50-yard line directly following his team\u27s high school football games. This Article reviews Kennedy v. Bremerton School District, from its inception through its current status, including the significance of Justice Alito\u27s concurring opinion issued in conjunction with the United States Supreme Court\u27s denial of Coach Kennedy\u27s Petition for Writ of Certiorari. After discussing the underlying facts, Part I provides an overview and analysis of the district and circuit courts\u27 rulings focusing particularly on the relationship between employee speech and the First Amendment religion clauses. Part II discusses the implications of Justice Alito\u27s concurring opinion in denying Coach Kennedy\u27s petition. And finally, Part III discusses the future of religious speech jurisprudence for public school employees, now that Justices Gorsuch and Kavanaugh are on the Supreme Court bench

Asymptotic Scaling of the Diffusion Coefficient of Fluctuating "Pulled" Fronts

We present a (heuristic) theoretical derivation for the scaling of the diffusion coefficient $D_f$ for fluctuating ``pulled'' fronts. In agreement with earlier numerical simulations, we find that as $N\to\infty$, $D_f$ approaches zero as $1/\ln^3N$, where $N$ is the average number of particles per correlation volume in the stable phase of the front. This behaviour of $D_f$ stems from the shape fluctuations at the very tip of the front, and is independent of the microscopic model.Comment: Some minor algebra corrected, to appear in Rapid Comm., Phys. Rev.