ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Broad-Band X-Ray Telescope spectroscopy of Xi Puppis (1993)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The Broad-Band X-Ray Telescope obtained moderate-resolution (about 90 eV) X-ray spectra of the O4 f star Xi Pup during the STS 35/Astro 1 mission in 1990 December. Despite the shortness of the observation (600 s), the data show a surprising amount of detail. We report the detection of an O absorption edge produced by ionized overlying wind material and K-shell line emission from Mg produced by a thermal plasma of temperature near 6 x 10 exp 6 K. The data are used to place constraints on the location, temperature, and amount of the X-ray-emitting gas, as well as the abundance and ionization of the wind material.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 412; 2; p. 792-796.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Properties of the massive X-ray binary 4U 1700 - 37 = HD 153919 (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The system parameters for the massive X-ray binary 4U 1700 - 37 are reexamined in the light of modern spectroscopic theory and new UV and X-ray data. The system is composed of HD 153919, an O6f star having a stronger wind, and an accreting neutron star. Revised parameters for the Of component are derived which are in accord with the parameters of single Of stars, which resolves the problem that 'the O star is undermassive by a factor of 2' formulated by Conti (1978). The ratio of the terminal velocity of the wind to the photospheric escape velocity agrees with those of O stars. The discrepancy between the values of the wind acceleration parameter, derived from X-ray and UV data, is resolved. The acceleration of the wind is similar to that of single OB star winds. It is suggested that the supernova explosion producing the neutron star in 4U 1700 - 37 occurred over a million years ago when HD 153919 was still on the main sequence.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 387; 340-346
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Circumstellar material around the massive close binary DH Cephei (1991)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The expanding atmosphere of the massive close binary DH Cephei is analyzed on the basis of data from ground-based polarimetry and spaceborne UV observations obtained with the IUE satellite. The mass loss from the system is estimated to be about 2 x 10 to the -6th solar mass/yr. This material can be divided into three classes: (1) wind material, which is hot gas driven from the stars via radiation pressure and reaching terminal velocity at a distance of 5a or greater; (2) scattering material, which may be the result of colliding winds or instabilities in the wind flow; and (3) small (0.1 micron) dust grains. The latter may originate in the cold high-density boundary formed as the wind from the binary plows into the ambient interstellar medium or, alternatively, may be the residue of the formation of stellar components.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 366; 308-317
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    H-beta photometry of V1010 Ophiuchi (1991)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An analysis is presented of previously unpublished intermediate and narrow band H-beta light curves of the short period eclipsing binary V1010 Oph. The temperature of the primary is determined directly by comparing the UV continuum with Kurucz model atmospheres and solve the broadband lightcurve using the Wilson-Devinney program. The present solution has the primary filling its Roche lobe while the secondary is detached from its lobe. An asymmetry in the light curve in which first quadrature (0.25 P) is brighter than the second quadrature (0.75 P) may be the result of local heating of the inner surface of the secondary by mass transfer from the primary. The present semidetached solution indicates that the system is probably evolved.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal (ISSN 0004-6256); 101; 1828-183
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    ASCA solid state imaging spectrometer observations of O stars (1994)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We report ASCA Solid State Imaging Spectrometer (SIS) X-ray observations of the O stars delta Ori and lambda Ori. The energy resolution of the SIS allows us to resolve features in the O star X-ray spectra which are not apparent in spectra obtained by X-ray spectrometers with lower energy resolution. SIS spectra from both stars show evidence of line emission, suggesting the thermal nature of the X-ray source. However, the observed line strengths are different for the two stars. The observed stellar X-ray spectra are not well described by isothermal models although absorbed thermal emission models with two or more temperatures can provide an adequate fit to the data. For both stars we present evidence of absorbing columns significantly larger than the known Interstellar Medium (ISM) columns, indicative of absorption by a circumstellar medium, presumably the stellar winds. In addition, the lambda Ori spectrum shows the presence of emission at energies greater than 3 keV which is not seen in the delta Ori spectrum.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 436; 1; p. L95-L98
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    The mass of the O6Iaf star HD 153919 (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The mass of the O component in the massive X-ray Binary 4U 1700-37 is reexamined, using the modern theory of stellar winds and applying it to X-ray light curves for the system and to UV wind line profiles. It is found that the mass of the O star is about 50 solar masses, in accord with the masses of other stars of similar spectral type. Thus, the problematic nature of the undermassive massive X-ray binaries appears to be resolved in favor of higher masses.
    Keywords: ASTROPHYSICS
    Type: Boulder-Munich Workshop on Hot Luminous Stars; Aug 06, 1988 - Aug 11, 1988; Boulder, CO; United States
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Winds and the underlying physical parameters of hot stars - An observational approach (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The predicted values of wind terminal velocity calculated using the formalism of Kudritzki et al. (1989) are compared with observed values for 4 OB binaries with well determined component masses, radii, and temperatures. The aim is to derive the value of the force multiplier parameter alpha appropriate to the winds from these stars.
    Keywords: ASTROPHYSICS
    Type: Boulder-Munich Workshop on Hot Luminous Stars; Aug 06, 1988 - Aug 11, 1988; Boulder, CO; United States
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    IUE observations of V Sagittae (1986)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: Observations of the nova-like variable V Sge are discussed, and the ground-based light curve is analyzed, compensating for the component interaction effect. Low-dispersion IUE spectra indicate that interstellar reddening is smaller than suggested from visible-band observations. The UV and visible continuum are modeled by a He-rich model and by a simple accretion disk, and the UV spectrum emission lines are used to determine ionization temperatures and a lower N(e) limit. The present data are consistent with the picture of the companion to the He star being embedded in an accretion disk, with the disk being large (of dimension comparable to that of the embedding Roche lobe as a result of vigorous mass transfer) at the time of the ground-based data, and with the disk having been diminished to a radius of the order of 200 times of the neutron star, at the time of the IUE spectra.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 306; 618-628
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...