arXiv subjects

P. Lampens

Publications and source records attributed to P. Lampens.

40 records · Page 3Linked to original sources

arXiv2000

Delta Scuti Stars in Stellar Systems: the interest of HD 220392 and HD 220391

The very wide double star CCDM 23239-5349 is an interesting study case of a pulsating star within a common origin pair or wide binary. Both stars are located in the Delta Scuti instability strip. Based on data obtained at La Silla (Chile), at the Swiss 0.7m and the ESO 0.5m telescopes, we found two periodicities of about 4.7 and 5.5 cycles per day (cpd) with amplitudes of 0.014 and 0.011 mag, respectively, for HD 220392, the brightest member of the system. The most dominant periodicity was also detected in the Hipparcos Epoch Photometry data. A similar period search on the (smaller) dataset obtained for the 1 mag fainter B-component, HD 220391, however shows no periodic behaviour with an amplitude significantly above the noise level of the data (about 0.006 mag).

astro-ph↗

arXiv2000

Delta Scuti stars in stellar systems: on the variability of HD 220392 and HD 220391

HD 220392 (HR 8895), the brightest member of the visual double star CCDM 23239-5349, is a new short-period variable bright star, probably of the Delta Scuti type. The period analysis performed on the complete set of definitive Geneva photometry as well as on the data obtained at the ESO 0.5m telescope shows two periodicities of about 4.7 and 5.5 cycles per day (cpd) with amplitudes of 0.014 and 0.011 mag respectively. A similar period search on the (smaller) dataset obtained for the 1 mag fainter B-component, HD 220391, however shows no periodicity with an amplitude significantly above the noise level of the data (about 0.006 mag). This difference in variability behaviour is discussed from the consideration that both stars form a common origin pair and are located in the Delta Scuti instability strip.

astro-ph↗

arXiv2000

Delta Scuti Stars in Stellar Systems: a Review

We present a list of delta Scuti stars in double and multiple systems, ranging from the very wide binaries to the very close ones such as spectroscopic and eclipsing systems including the optical visual pairs which are of no further use here. Our aim is to group the information from the binarity on the one hand and the pulsational characteristics on the other hand for as complete a sample as possible of delta Scuti stars in stellar systems. A selection of 18 well-documented cases, taking care that every type of binary is being represented, is discussed more extensively.

astro-ph↗

arXiv1999

CCD Photometry and Astrometry for Visual Double and Multiple Stars of the HIPPARCOS Catalogue - I. Presentation of the large scale project

A description is given of the activities of an international working group created with the aim of obtaining both photometric and astrometric observations of visual double and multiple stars with angular separations in the range of one to fifteen arcseconds, that formed part of the HIPPARCOS Input Catalogue. The scientific aims and realisations of this European network are given. About 50 observational missions have been carried out in both hemispheres according to a pre-defined protocol. We describe the general and specifically designed methods used for the reduction of large amounts of CCD observations of double stars and give an outline of the results already presented and soon expected.

astro-ph↗