4,003 research outputs found
ROTSE observations of the young cluster IC 348
CCD observations of stars in the young cluster IC 348 were obtained from 2004
August to 2005 January with a 0.45 m ROTSEIIId robotic reflecting telescope at
the Turkish National Observatory site, Bakirlitepe, Turkey. The timing analysis
of selected stars whose X-Ray counterpart were detected by Chandra X-Ray
Observatory were studied. The time series of stars were searched for rotational
periodicity by using different period search methods. 35 stars were found to be
periodic with periods ranging from 0.74 to 32.3 days. Eighteen of the 35
periodic stars were new detections. Four of the new detections were CTTSs and
the others were WTTSs and G type (or unknown spectral class) stars. In this
study, we confirmed the stability of rotation periods of TTauri stars. The
periods obtained by Cohen et al. and us were different by 1%. We also confirmed
the 3.24 h pulsation period of H254 which is a delta Scuti type star as noted
by Ripepi et al. but the other periods detected by them were not found. We
examined correlation between X-ray luminosity and rotational period of our
sample of TTSs. There is a decline in the rotational period with X-ray
luminosity for late type TTSs.Comment: 15 pages, 14 figures, accepted for publication in Astronomical
Journa
Some Effects of Copper Sulfate, Copper Oxide and 4-Nitrophenylarsonic Acid on Aortic Rupture and Growth of Turkeys
Previous studies have shown that adding copper, as copper sulfate, to raise the copper level to 120 ppm in low and high protein diets resulted in Increased weight gains and reduced incidence of aortic ruptures. Without copper additives the diets contain 8 to 12 ppm Cu. In all previous studies, 4-nitrophenylarsonic acid was used as a blackhead preventative. It is acknowledged that 4-nitro depressed growth. Also sulfate ions, from various sources, have shown a sparing effect on the sulfur amino acids, thereby promoting growth. These facts raised several questions. Does the added copper promote growth by suppressing toxicity of 4-nitro or by adding sulfate ions to the diet? Also, does the added copper increase the amount of copper stored in the liver
Turkey Performance as Influenced by Egg Dipping
This experiment has not been completed. The data shown were obtained at 12 weeks. Eggs from a breeder flock with a known history of Mycoplasma gallisepticum infection were dipped in a solution containing a combination of 2800 ppm Tylan and 2000 ppm Neomycin before incubation. The eggs were first dipped in warm water (98°F) for 5 minutes and then into the cold (38°F) antibiotic solution for 10 minutes. Batches of 50 eggs increased in weight 6 to 18 grams from this treatment, thus showing an average uptake of 0.68 mcg of tylosin and 0.49 mcg of Neomycin of the eggs were 3 weeks old when set and the balance 1 week. Therefore, the old and young eggs were set separately. Results would indicate that the age of the eggs and dipping affected 7-day fertility and hatchability. Last year the eggs were dipped using a vacuum method
Some Effects of Copper and High and Low Protein Diets on Aortic Rupture and Growth of Turkets
In other studies using high and low protein diets for growing turkeys, aortic ruptures frequently caused high death losses, particularly among the large type males. Inadequate elastin formation and the resulting lack of strength and elastic ity may be contributing factors in aortic failures. The aortic rupture usually occurs in the lower portion of the artery located between the kidneys. Copper and lysine are both involved in elastin synthesis
Comparisons of a Midget vs. a Standard Sized Strain of Laying Hens
Two new strains, one standard sized and the other approximately 70% as large, were acquired and tested for performance. The chicks were grown in floor pens to 20 weeks of age on standard growing diets and then placed in 12- and 16-inch layer cages. The hens were placed in cages at normal and high density, i.e., 3 or 4 hens per 12-inch cage and 4 or 5 hens per 16-inch cage. All were fed the same diet, 16% crude protein and 2900 Gal. M.E. The test lasted 10 months
The power of low-resolution spectroscopy: On the spectral classification of planet candidates in the ground-based CoRoT follow-up
Planetary transits detected by the CoRoT mission can be mimicked by a
low-mass star in orbit around a giant star. Spectral classification helps to
identify the giant stars and also early-type stars which are often excluded
from further follow-up.
We study the potential and the limitations of low-resolution spectroscopy to
improve the photometric spectral types of CoRoT candidates. In particular, we
want to study the influence of the signal-to-noise ratio (SNR) of the target
spectrum in a quantitative way. We built an own template library and
investigate whether a template library from the literature is able to reproduce
the classifications. Including previous photometric estimates, we show how the
additional spectroscopic information improves the constraints on spectral type.
Low-resolution spectroscopy (1000) of 42 CoRoT targets covering a
wide range in SNR (1-437) and of 149 templates was obtained in 2012-2013 with
the Nasmyth spectrograph at the Tautenburg 2m telescope. Spectral types have
been derived automatically by comparing with the observed template spectra. The
classification has been repeated with the external CFLIB library.
The spectral class obtained with the external library agrees within a few
sub-classes when the target spectrum has a SNR of about 100 at least. While the
photometric spectral type can deviate by an entire spectral class, the
photometric luminosity classification is as close as a spectroscopic
classification with the external library. A low SNR of the target spectrum
limits the attainable accuracy of classification more strongly than the use of
external templates or photometry. Furthermore we found that low-resolution
reconnaissance spectroscopy ensures that good planet candidates are kept that
would otherwise be discarded based on photometric spectral type alone.Comment: accepted for publication in Astronomische Nachrichten; 12 pages, 4
figures, 7 table
Testing evolutionary tracks of Pre-Main Sequence stars: the case of HD113449
Evolutionary tracks are of key importance for the understanding of star
formation. Unfortunately, tracks published by various groups differ so that it
is fundamental to have observational tests. In order to do this, we intend to
measure the masses of the two components of the Pre-Main Sequence binary
HD113449 by combining radial velocity measurements taken with HARPS, with
infrared interferometric data using AMBER on the VLTI. The spectroscopic orbit
that has already been determined, combined with the first AMBER measurement,
allows us to obtain a very first estimation of the inclination of the binary
system and from this the masses of the two stars. More AMBER measurements of HD
113449 are needed to improve the precision on the masses: in the ESO period P82
two new measurements are scheduled.Comment: 4 pages, 3 figures; to appear in proceedings of Cool Star 15
conference, St.Andrews 200
An algorithm for correcting CoRoT raw light curves
We introduce the CoRoT detrend algorithm (CDA) for detrending CoRoT stellar
light curves. The algorithm CDA has the capability to remove random jumps and
systematic trends encountered in typical CoRoT data in a fully automatic
fashion. Since enormous jumps in flux can destroy the information content of a
light curve, such an algorithm is essential. From a study of 1030 light curves
in the CoRoT IRa01 field, we developed three simple assumptions which upon CDA
is based. We describe the algorithm analytically and provide some examples of
how it works. We demonstrate the functionality of the algorithm in the cases of
CoRoT0102702789, CoRoT0102874481, CoRoT0102741994, and CoRoT0102729260. Using
CDA in the specific case of CoRoT0102729260, we detect a candidate exoplanet
around the host star of spectral type G5, which remains undetected in the raw
light curve, and estimate the planetary parameters to be Rp=6.27Re and P=1.6986
days.Comment: 8 pages, 13 figure
An infrared imaging search for low-mass companions to members of the young nearby beta Pic and Tucana/Horologium associations
We present deep high dynamic range infrared images of young nearby stars in
the Tucana/Horologium and beta Pic associations, all ~ 10 to 35 Myrs young and
at ~10 to 60 pc distance. Such young nearby stars are well-suited for direct
imaging searches for brown dwarf and even planetary companions, because young
sub-stellar objects are still self-luminous due to contraction and accretion.
We performed our observations at the ESO 3.5m NTT with the normal infrared
imaging detector SofI and the MPE speckle camera Sharp-I. Three arc sec north
of GSC 8047-0232 in Horologium a promising brown dwarf companion candidate is
detected, which needs to be confirmed by proper motion and/or spectroscopy.
Several other faint companion candidates are already rejected by second epoch
imaging. Among 21 stars observed in Tucana/Horologium, there are not more than
one to five brown dwarf companions outside of 75 AU (1.5" at 50 pc); most
certainly only < 5 % of the Tuc/HorA stars have brown dwarf companions (13 to
78 Jupiter masses) outside of 75 AU. For the first time, we can report an upper
limit for the frequency of massive planets (~ 10 M_jup) at wide separations (~
100 AU) using a meaningfull and homogeneous sample: Of 11 stars observed
sufficiently deep in beta Pic (12 Myrs), not more than one has a massive planet
outside of ~ 100 AU, i.e. massive planets at large separations are rare (< 9
%).Comment: Astronomische Nachrichten, in pres
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