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Photometric studies of three multiperiodic β Cephei stars: β CMa, 15 CMa and KZ Mus
We have carried out single and multisite photometry of the three βCephei stars β and 15 CMa as well as KZ Mus. For the two stars inCMa, we obtained 270h of measurement in the Strömgren uvy andJohnson V filters, while 150h of time-resolved Strömgren uvyphotometry was acquired for KZ Mus. All three stars are multiperiodicvariables, with three (β CMa) and four (15 CMa, KZ Mus) independentpulsation modes. Two of the mode frequencies of 15 CMa are newdiscoveries and one of the known modes showed amplitude variations overthe last 33yr. Taken together, this fully explains the diverse behaviourof the star reported in the literature.Mode identification by means of the amplitude ratios in the differentpassbands suggests one radial mode for each star. In addition, βCMa has a dominant l = 2 mode while its third mode is non-radial withunknown l. The non-radial modes of 15 CMa, which are l <= 3, form analmost equally split triplet that, if physical, would imply that we seethe star under an inclination angle larger than 55°. The strongestnon-radial mode of KZ Mus is l = 2, followed by the radial mode and adipole mode. Its weakest known mode is non-radial with unknown l,confirming previous mode identifications for the pulsations of the star.The phased light curve for the strongest mode of 15 CMa has a descendingbranch steeper than the rising branch. A stillstand phenomenon duringthe rise to maximum light is indicated. Given the low photometricamplitude of this non-radial mode this is at first sight surprising, butit can be explained by the aspect angle of the mode.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| The Spacelab-1 Very Wide Field Survey of UV-excess objects. IV. The performance of the instrument in combination with optical photometry as a means of identifying stars with peculiar properties.
UV (195 nm) and Stroemgren uvby photometry of a 110 square degree fieldat high southern galactic latitudes are analyzed through a comparison ofi) UV magnitudes for 57 stars of various types common to the publishedTD1 catalogue and the Very Wide Field Camera (VWFC); and ii) observedand theoretical two-colour diagrams. The higher sensitivity of the VWFC(=~0.5magnitude) and its more complete survey are exemplified by thedetection and UV measurement of a series of objects with moderateUV-excess in addition to detection of some very blue objects of variousnature down to fainter than 12th magnitude in the optical domain. Adeeper survey with a VWFC-type instrument could provide a completesample for studies of the group properties of faint blue stars. Duringthe uvby reductions it was found that the usual procedure of plottingresiduals as functions of declination, hour angle and airmass can be apowerful and diagnostic test of photometer rigidity.
| Multicolour Polarization and Co/ Observations Towards a Dark Filament in Musca
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993MNRAS.265....1A&db_key=AST
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Osservazione e dati astrometrici
| Costellazione: | Mosca |
| Ascensione retta: | 12h40m17.13s |
| Declinazione: | -71°38'42.7" |
| Magnitudine apparente: | 7.843 |
| Distanza: | 369.004 parsec |
| Moto proprio RA: | -17.8 |
| Moto proprio Dec: | -6.5 |
| B-T magnitude: | 7.971 |
| V-T magnitude: | 7.854 |
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