The massive binary CPD-41°7742 - I. High-resolution optical spectroscopy

in Astronomy and Astrophysics (2003), 405(3), 1063-1074

We present the results of a spectroscopic campaign on the early-type binary CPD-41degrees 7742. For the first time, we unambiguously detect the secondary's spectral signature and derive an accurate ... [more ▼]

We present the results of a spectroscopic campaign on the early-type binary CPD-41degrees 7742. For the first time, we unambiguously detect the secondary's spectral signature and derive an accurate orbital solution for both components of the system. We confirm that the orbit displays a slight but definite eccentricity (e=0.027+/-0.006) despite the short period (P=2.44070+/-0.00043 days). Previous radial velocity measurements available in the literature constitute together with our new observations a data set that spans more than 30 years. The combined primary orbital solution inferred is in excellent agreement with our solution and gives a period P=2.44062+/-0.00005 days. Based on spectroscopic criteria, we derive a spectral and luminosity classification of O9 III + B1 III. However, the luminosities and radii inferred from the membership of NGC6231 rather indicate lower luminosity classes. We show that the equivalent widths of well isolated primary lines display variations that suggest that CPD-41degrees 7742 is an eclipsing binary. This makes CPD-41degrees 7742 the second known SB2 eclipsing early-type binary of the NGC 6231 cluster. We approximately constrain the inclination of the system i(min) approximate to 60degrees. This may indicate that the system does not offer enough room for two stars with radii typical of giant stars and lends further support to a less evolved luminosity classification for at least one of the objects. [less ▲]

Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990

in Astronomy and Astrophysics. Supplement Series (1993), 102

In this paper we present the second catalogue of photometric data in the Strömgren system obtained during the period October 1986- September 1990 in the framework of the Long-Term Photometry of Variables ... [more ▼]

In this paper we present the second catalogue of photometric data in the Strömgren system obtained during the period October 1986- September 1990 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. The catalogue is available in computer readable form at the Centre de Données de Strasbourg. [less ▲]

Long-term stability of classical photometry

in The Messenger (1992), 70

Not Available

Long-Term Photometry of Variables at ESO. I.

Report (1991)

Not Available

BW Vulpeculae - A coordinated campaign of photoelectric photometry from thirteen observatories

in Astronomy and Astrophysics. Supplement Series (1986), 66

This paper contains the fully reduced observational data on the Beta Cep star BW Vul, which were obtained in the summer of 1982 during an international campaign at thirteen observatories in the northern ... [more ▼]

This paper contains the fully reduced observational data on the Beta Cep star BW Vul, which were obtained in the summer of 1982 during an international campaign at thirteen observatories in the northern hemisphere. Useful measurements were made during a total of 486 hours. All observations have been assigned proper weights and were binned in time intervals of 90 seconds. In this manner the observations were combined into single data points which resulted in about 6000 mean differential measurements. A preliminary ephemeris for 1982 is derived, and a mean lightcurve is given. The results indicate a fair degree of stability in the shape and in the amplitude of the lightcurve. Possible variations exist in the morphology of the stillstand phenomenon. [less ▲]

The frequency of Ap-stars with long rotation periods

in Astronomy and Astrophysics (1984), 132

Light variability was observed over time intervals of months to years in the stars HD 55540, HD 71066, HD 94660, and HD 187474. The significance of these results is discussed in terms of the frequency of ... [more ▼]

Light variability was observed over time intervals of months to years in the stars HD 55540, HD 71066, HD 94660, and HD 187474. The significance of these results is discussed in terms of the frequency of chemically peculiar CP2 stars showing (light) variability with periods longer than one month. This frequency, relative to the whole CP2 population, must lie somewhere between 4 and 16 percent. Observations, properly distributed in time, of a small subgroup of CP2 stars will be sufficient to obtain an accurate ratio of the number of LP-CP2 stars to the total number of CP2 stars. These observations, when continued until the periodicity is detected, could contribute also to the discussion whether these long periods should be identified with the rotation period. [less ▲]

The International Photometric Observing Campaign on BW VUL : First Results

in Liege International Astrophysical Colloquia (1984)

Not Available