scholarly journals ASCA Observations of the Eclipsing IP XY Ari

1997 ◽  
Vol 163 ◽  
pp. 794-794
Author(s):  
Eric M. Schlegel ◽  
Koji Mukai ◽  
M. Ishida
Keyword(s):  
Orbital Period ◽  
Background Subtraction ◽  
Molecular Cloud ◽  
Preliminary Analysis ◽  
Pulse Period ◽  
Optical Extinction ◽  
Sample Spectrum

AbstractWe describe the ASCA observation of the eclipsing intermediate polar (IP) XY Ari (=H0253+19). This system was first discussed by Patterson & Halpern (1990, ApJ, 361, 173) as a possible IP based upon the HEAO-1 data. This system is impossible to study in the optical or ultraviolet because of the 12 mag of optical extinction associated with the molecular cloud Lynds 1457=MBM 12. The system has an orbital period of 0.2526 day and a pulse period of 208 sec. Our preliminary analysis of the ASCA data shows that the eclipse is nearly total (the precision of the background subtraction sets the limit). The eclipse ingress and egress occur very quickly, although we have not yet derived accurate numbers. There are sufficient photons that we can perform crude phase-resolved spectroscopy. The resulting spectra, each covering about 1/4 of the orbit, show that the Fe Kα line is not constant as a function of phase. A sample spectrum is reproduced below. We expect to submit a paper describing the results to the ApJ before the end of 1996.

scholarly journals Large column densities and [12CII] 158 μm self-absorption in Orion B

2012 ◽  
Vol 8 (S292) ◽  
pp. 57-58
Author(s):  
J. Stutzki ◽  
U. U. Graf ◽  
R. Simon ◽  
S. W. J. Colgan ◽  
X. Guan ◽  
...  
Keyword(s):  
Present State ◽  
Molecular Cloud ◽  
Preliminary Analysis ◽  
State Of The Art ◽  
The Self ◽  
Absorption Component ◽  
Warm Core ◽  
High Column

AbstractWe present a preliminary analysis of the self-absorbed [CII]-spectra observed with SOFIA/GREAT towards NGC 2024. Together with the detected [13CII] hyperfine satellites, the observed spectra require surprisingly high column densities of C+, both in the warm core and the foreground absorption component. Such high column densities are a challenge to explain with present state-of-the-art PDR models of the UV/molecular cloud interaction.

A new optical extinction law and distance estimate for the Taurus-Auriga molecular cloud

1994 ◽  
Vol 108 ◽  
pp. 1872 ◽  
Author(s):  
S. J. Kenyon ◽  
D. Dobrzycka ◽  
L. Hartmann
Keyword(s):  
Molecular Cloud ◽  
Distance Estimate ◽  
Optical Extinction

scholarly journals The X-ray Transient EXO 2030+375

1987 ◽  
Vol 125 ◽  
pp. 203-203
Author(s):  
A.N. Parmar ◽  
N.E. White ◽  
L. Stella ◽  
P. Ferri
Keyword(s):  
Orbital Period ◽  
Mass Function ◽  
Pulse Period ◽  
X Ray ◽  
Imaging Telescope ◽  
Be Star ◽  
X Ray Binaries

EXOSAT has observed a bright transient X-ray pulsar EXO 2030+375 that decayed in intensity by a factor ∼5000 between 1985 May and August. The variations in 42s pulse period enable an orbital period of 37.9±1.3 days with an eccentricity of 0.31±0.02 to be determined. The spin-up timescale of ∼30 years suggests that this is a very large outburst of order a few 1038 ergs/s. The mass function of 5Mo is consistent with the unidentified companion being a Be star, similar to many other pulsing X-ray binaries. The position of EXO 2030+375, obtained with the EXOSAT Imaging Telescope, is RA: 20 30 21.25, Decl. +37 27 51 (1950; with an uncertainty radius of 10″).

scholarly journals The EUV Excess in Magnetic Cataclysmic Variables

1996 ◽  
Vol 152 ◽  
pp. 325-329
Author(s):  
John K. Warren ◽  
Koji Mukai
Keyword(s):  
Magnetic Field ◽  
Orbital Period ◽  
White Dwarf ◽  
Preliminary Analysis ◽  
Cataclysmic Variables ◽  
X Rays ◽  
System Parameters ◽  
Magnetic Capture ◽  
Magnetic Cataclysmic Variables ◽  
Capture Radius

We present preliminary analysis of EUVE pointed data of 8 magnetic cataclysmic variables. Blackbody temperatures, luminosities, and interstellar columns have been better constrained. Using these luminosities we look for correlations between the EUV excess (over optical and hard X-rays) and various system parameters. While it appears there is no correlation between the EUV excess and the system inclination and orbital period, correlations are suggested between the EUV excess and the longitude of the accretion spot, the colatitude of the accretion spot, the white dwarf magnetic field, and the magnetic capture radius.

Asteroseismology of Pulsating sdB Stars Observed at Catania Astrophysical Observatory

2003 ◽  
Vol 12 (2) ◽  
Author(s):  
A. Bonanno ◽  
A. Frasca ◽  
A. F. Lanza ◽  
R. Ventura ◽  
B. Mignemi ◽  
...  
Keyword(s):  
Time Series ◽  
Binary System ◽  
Orbital Period ◽  
Preliminary Analysis ◽  
Precise Determination ◽  
Eclipsing Binary ◽  
Sdb Stars ◽  
Cassegrain Telescope

AbstractWe present analysis of the data collected during three years of photometric campaigns at the 91 cm Cassegrain telescope of the Catania Astrophysical Observatory to observe the pulsating subdwarf B star PG 1336-018. For this eclipsing binary system, we obtained a precise determination of the orbital period which turns out to be P = 0.10101599±0.00000002 days. Time-series photometry reveals pulsation periods near 174 and 184 seconds. We also discuss a preliminary analysis of the data obtained in 2002 for the pulsating subdwarf PG 1325+101.

scholarly journals The Be/X-Ray System HDE 245770/A0535+26 in an Active Phase

1987 ◽  
Vol 92 ◽  
pp. 309-310
Author(s):  
C. Bartolini ◽  
M. Burger ◽  
E.L. van Dessel ◽  
F. Giovannelli ◽  
A. Guarnieri ◽  
...  
Keyword(s):  
Neutron Star ◽  
Orbital Period ◽  
Active Phase ◽  
Emission Lines ◽  
Pulse Period ◽  
X Ray ◽  
Sudden Appearance

The principal aim is to report on the sudden appearance and disappearance of (mainly) Fe II emission lines in the Be/X-ray system HDE 24-5770/ A0535+26, about 24 days before an X-ray outburst was observed. The system is characterized as an 09-7 Ille star of mass 20-25 M⊙, accompanied by a neutron star (X-ray pulse period ≃104 s), with orbital period -110 d, eccentricity > 0.3; for a more complete description see Giovannelli et al. (1985) or de Loore et al. (1984). X-ray outbursts have been observed recurrently, obviously connected with periastron passage of the neutron star triggering gas infall onto it. The observed X-ray outbursts are of varied strength, from barely detectabl to 3 Crab units at peak (Nagase et al. (1982), Giovannelli et al. (1984)). A weak X-ray event took place on December 13, 1981.

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

RSCVn Stars in the Southern Hemisphere

1979 ◽  
Vol 46 ◽  
pp. 371-384 ◽  
Author(s):  
J.B. Hearnshaw
Keyword(s):  
Light Curve ◽  
Southern Hemisphere ◽  
Orbital Period ◽  
Binary Stars ◽  
Small Amplitude ◽  
Light Variation ◽  
Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

1992 ◽  
Vol 50 (2) ◽  
pp. 1622-1623
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers
Keyword(s):  
Background Subtraction ◽  
Electron Probe ◽  
Detection System ◽  
Higher Order ◽  
Light Elements ◽  
Strong Suppression ◽  
Electron Probe Microanalyzer ◽  
Quantitative Epma ◽  
Peak Count ◽  
Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

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