IAUC 4426 available at Central Bureau for Astronomical Telegrams. IAUC 4426 available at Central ... more IAUC 4426 available at Central Bureau for Astronomical Telegrams. IAUC 4426 available at Central Bureau for Astronomical Telegrams.
ABSTRACT In this study, we investigate the period changes of eight short-period Type II Cepheids ... more ABSTRACT In this study, we investigate the period changes of eight short-period Type II Cepheids of the BL Her subtype, i.e. with periods in the 1–4 d range. The O − C diagrams for these stars are constructed using all suitable observational data from ground and space surveys. This spans a time interval of over one century and includes digitized photographic plates as well as photometry from the literature. The O − C diagrams show parabolic evolutionary trends, which indicate the presence of both increasing and decreasing periods for these eight short-period stars. These period changes are in good agreement with the recent theoretical evolutionary framework and stellar evolution models for BL Her stars. The pulsation stability test proposed by Lombard and Koen also suggests that the changes in the periods are real.
IUE observations providing the first ultraviolet spectroscopic data of the X-ray source Sco X-1 a... more IUE observations providing the first ultraviolet spectroscopic data of the X-ray source Sco X-1 are presented and discussed. The IUE data were obtained in the low resolution mode and cover the wavelength range 1150-3200 A. Data were obtained at many different phases and cycles in the binary period of the system of 0d.8. The short wavelength IUE spectra are dominated
Monthly Notices of the Royal Astronomical Society, Dec 1, 1990
La photometrie JHK d'une aire de 1°× 2°, incluant le centre galactique, est presentee. Les di... more La photometrie JHK d'une aire de 1°× 2°, incluant le centre galactique, est presentee. Les diagrammes magnitude-couleur sont analyses. Une carte de l'absorption interstellaire est realisee. La distribution des etoiles, en fonction de la distance angulaire au centre galactique et de la magnitude apparente, est determinee.
Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning... more Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning the first 1200 days of its outburst which began in June 1988. The effects of the outburst were restricted to the wavelength interval 2200<λ<7500 A. The progress of the event was followed through two maxima and two eclipses of the hot source by the M5 III companion. An orbital period of 650 days was derived from the eclipses. At no stage of the outburst did the luminosity approach the Eddington value, and no material was ejected from the system
Feltzing Zhao Walton Whitelock Setting the Scene for Gaia and LAMOST IAU Symposium No. 298 20-24 ... more Feltzing Zhao Walton Whitelock Setting the Scene for Gaia and LAMOST IAU Symposium No. 298 20-24 May 2013 Lijiang,China Gaia is an ambitious satellite mission to chart a three-dimensional map of the Milky Way. By measuring the proper motions and parallaxes for a billion stars, Gaia is set to transform the way we study the composition, formation and evolution of our galaxy. Concurrently the LAMOST survey facility in China will make a complementary spectral survey of millions of objects in much of the northern sky. This volume, comprising the reviews and contributed talks presented at IAU Symposium 298, is an up-to-date review of what we know about the Milky Way as a galaxy prior to the launch of Gaia. It covers many topics ranging from the status of dynamical simulations, photometric and spectroscopic surveys, as well as interstellar matter in the Milky Way and detailed studies of stellar atmospheres. The expert reviews will interest all those working on Milky Way astronomy as well as galaxy formation and evolution.
IAUC 4426 available at Central Bureau for Astronomical Telegrams. IAUC 4426 available at Central ... more IAUC 4426 available at Central Bureau for Astronomical Telegrams. IAUC 4426 available at Central Bureau for Astronomical Telegrams.
ABSTRACT In this study, we investigate the period changes of eight short-period Type II Cepheids ... more ABSTRACT In this study, we investigate the period changes of eight short-period Type II Cepheids of the BL Her subtype, i.e. with periods in the 1–4 d range. The O − C diagrams for these stars are constructed using all suitable observational data from ground and space surveys. This spans a time interval of over one century and includes digitized photographic plates as well as photometry from the literature. The O − C diagrams show parabolic evolutionary trends, which indicate the presence of both increasing and decreasing periods for these eight short-period stars. These period changes are in good agreement with the recent theoretical evolutionary framework and stellar evolution models for BL Her stars. The pulsation stability test proposed by Lombard and Koen also suggests that the changes in the periods are real.
IUE observations providing the first ultraviolet spectroscopic data of the X-ray source Sco X-1 a... more IUE observations providing the first ultraviolet spectroscopic data of the X-ray source Sco X-1 are presented and discussed. The IUE data were obtained in the low resolution mode and cover the wavelength range 1150-3200 A. Data were obtained at many different phases and cycles in the binary period of the system of 0d.8. The short wavelength IUE spectra are dominated
Monthly Notices of the Royal Astronomical Society, Dec 1, 1990
La photometrie JHK d'une aire de 1°× 2°, incluant le centre galactique, est presentee. Les di... more La photometrie JHK d'une aire de 1°× 2°, incluant le centre galactique, est presentee. Les diagrammes magnitude-couleur sont analyses. Une carte de l'absorption interstellaire est realisee. La distribution des etoiles, en fonction de la distance angulaire au centre galactique et de la magnitude apparente, est determinee.
Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning... more Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning the first 1200 days of its outburst which began in June 1988. The effects of the outburst were restricted to the wavelength interval 2200<λ<7500 A. The progress of the event was followed through two maxima and two eclipses of the hot source by the M5 III companion. An orbital period of 650 days was derived from the eclipses. At no stage of the outburst did the luminosity approach the Eddington value, and no material was ejected from the system
Feltzing Zhao Walton Whitelock Setting the Scene for Gaia and LAMOST IAU Symposium No. 298 20-24 ... more Feltzing Zhao Walton Whitelock Setting the Scene for Gaia and LAMOST IAU Symposium No. 298 20-24 May 2013 Lijiang,China Gaia is an ambitious satellite mission to chart a three-dimensional map of the Milky Way. By measuring the proper motions and parallaxes for a billion stars, Gaia is set to transform the way we study the composition, formation and evolution of our galaxy. Concurrently the LAMOST survey facility in China will make a complementary spectral survey of millions of objects in much of the northern sky. This volume, comprising the reviews and contributed talks presented at IAU Symposium 298, is an up-to-date review of what we know about the Milky Way as a galaxy prior to the launch of Gaia. It covers many topics ranging from the status of dynamical simulations, photometric and spectroscopic surveys, as well as interstellar matter in the Milky Way and detailed studies of stellar atmospheres. The expert reviews will interest all those working on Milky Way astronomy as well as galaxy formation and evolution.
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