Religion of Nazi Germany

https://digital.kenyon.edu/rarebooks/1016/thumbnail.jp

Pulsating B-type stars in the young open cluster h Persei (NGC 869)

We announce the discovery of six Beta Cephei stars and many other variable stars in the young open cluster h Persei (NGC 869). The cluster seems to be very rich in variable B-type stars, similarly to its twin, Chi Persei (NGC 884).Comment: 5 pages, 5 figures, Proc. HELAS-II conference, Goettingen, 20-24 August 200

KIC 8302197 : a non-rotating or low-inclination pulsating subdwarf B star observed with the Kepler spacecraft

We present our analysis of Kepler data of a pulsating subdwarf B star, KIC 8302197. We used Q5-17 data and applied a Fourier technique to extract 30 significant pulsation modes. We searched for multiplets and period-spacing sequences to perform a mode identification and to derive a rotation period. To our surprise, KIC 8302197 does not show any multiplets. We explain the lack of multiplets by either a very slow rotation (longer than ~1000 days) or a unique (pole-on) orientation of the pulsation axis. Our mode identification relied solely on period spacing. We were successful in identifying modal degrees of most of the detected modes. An analysis of the period stability did not show any evidence of a companion to the host star. In addition to photometric data, several spectroscopic observations were collected. Our twelve radial-velocity measurements constrain a possible orbital radial-velocity amplitude to be smaller than about 10 km s-1. Furthermore, based on color indices we constrained a possible companion to be an M or later type main sequence, a compact or a substellar object. We found that the atmospheric parameters (Teff = 27 450 ± 200 K, log g = 5.438 ± 0.033 dex, and log (nHe /nH) = −2.56 ± 0.07 dex) of KIC 8302197 are consistent with other slow pulsating subdwarf B stars. From the optical spectra we derived C, N, O, Si and Fe abundances, and set an upper limit for the S abundance

A Catalog of Spectroscopically Confirmed White Dwarfs from the Sloan Digital Sky Survey Data Release 4

We present a catalog of 9316 spectroscopically confirmed white dwarfs from the Sloan Digital Sky Survey Data Release 4. We have selected the stars through photometric cuts and spectroscopic modeling, backed up by a set of visual inspections. Roughly 6000 of the stars are new discoveries, roughly doubling the number of spectroscopically confirmed white dwarfs. We analyze the stars by performing temperature and surface gravity fits to grids of pure hydrogen and helium atmospheres. Among the rare outliers are a set of presumed helium-core DA white dwarfs with estimated masses below 0.3 Msun, including two candidates that may be the lowest masses yet found. We also present a list of 928 hot subdwarfs.Comment: Accepted by the Astrophysical Journal Supplements, 25 pages, 24 figures, LaTeX. The electronic catalog, as well as diagnostic figures and links to the spectra, is available at http://das.sdss.org/wdcat/dr4

A Strategy for Finding Near Earth Objects with the SDSS Telescope

We present a detailed observational strategy for finding Near Earth Objects (NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate strategies in normal, unbinned mode as well as binning the CCDs 2x2 or 3x3, which affects the sky coverage rate and the limiting apparent magnitude. We present results from 1 month, 3 year and 10 year simulations of such surveys. For each cadence and binning mode, we evaluate the possibility of achieving the Spaceguard goal of detecting 90% of 1 km NEOs (absolute magnitude H <= 18 for an albedo of 0.1). We find that an unbinned survey is most effective at detecting H <= 20 NEOs in our sample. However, a 3x3 binned survey reaches the Spaceguard Goal after only seven years of operation. As the proposed large survey telescopes (PanStarss; LSST) are at least 5-10 years from operation, an SDSS NEO survey could make a significant contribution to the detection and photometric characterization of the NEO population.Comment: Accepted by AJ -- 12 pages, 11 figure

Lessons Learned from Sloan Digital Sky Survey Operations

Astronomy is changing. Large projects, large collaborations, and large budgets are becoming the norm. The Sloan Digital Sky Survey (SDSS) is one example of this new astronomy, and in operating the original survey, we put in place and learned many valuable operating principles. Scientists sometimes have the tendency to invent everything themselves but when budgets are large, deadlines are many, and both are tight, learning from others and applying it appropriately can make the difference between success and failure. We offer here our experiences well as our thoughts, opinions, and beliefs on what we learned in operating the SDSS.Comment: Conference Proceedings, SPIE 200

Eclipsing binaries in open clusters. III. V621 Per in chi Persei

V621 Persei is a detached eclipsing binary in the open cluster chi Persei which is composed of an early B-type giant star and a main sequence secondary component. From high-resolution spectroscopic observations and radial velocities from the literature, we determine the orbital period to be 25.5 days and the primary velocity semiamplitude to be K = 64.5 +/- 0.4 km/s. No trace of the secondary star has been found in the spectrum. We solve the discovery light curves of this totally-eclipsing binary and find that the surface gravity of the secondary star is log(g_B) = 4.244 +/- 0.054 (cm/s). We compare the absolute masses and radii of the two stars in the mass--radius diagram, for different possible values of the primary surface gravity, to the predictions of stellar models. We find that log(g_A) is approximately 3.55, in agreement with values found from fitting Balmer lines with synthetic profiles. The expected masses of the two stars are 12 Msun and 6 Msun, and the expected radii are 10 Rsun and 3 Rsun. The primary component is near the blue loop stage in its evolution.Comment: Accepted for publication in MNRAS (10 pages, 5 figures

Mt. Suhora M dwarf survey - Detection of eight short-period variable stars

The Mt. Suhora M\,dwarf survey searching for pulsations in low mass main sequence stars has acquired CCD photometry of 46 M\,dwarf stars during the first year of the project (Baran et al 2011). As a by-product of this search hundreds field stars have been checked for variability. This paper presents our initial result of a search for periodic variables in field stars observed in the course of the survey. On the basis of the periodicity and the shape of the light curves, eight new variables has been detected, among which five are $\delta$ Scuti stars and three likely RR Lyrae stars. Although variation in one of the stars has been previously detected, it was classified incorrectly. To support our classification, in August 2010, we performed spectroscopic observations to derive spectral types and luminosity classes for all eight variable stars.Comment: Accepted for publication in New Astronomy, 12 pages, 1 table, 9 figure

Spectral Analyses of DO White Dwarfs and PG1159 Stars from the Sloan Digital Sky Survey

SDSS (DR1 and DR2) has recently proposed 7 new DO white dwarfs as well as 6 new PG1159 stars. This is a significant increase in the known number of DOs and PG1159 stars. Our spectral analyses provide stellar parameters which can then be used to derive constraints for the evolution of H-deficient white dwarfs. A comprehensive understanding of these objects is still severely hampered by low-number statistics.Comment: 4 pages, 4 figures, 1 table, requires asp2004.sty, to appear in the proceedings of the 14th European Workshop on White Dwarfs, eds. D. Koester and S. Moehler, ASP Conf. Se