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HD 31640


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The nearby ellipsoidal variable TV Pictoris
TVPic is identified as a bright, near-contact mid-A+early-F binary seenunder a moderate inclination of 54degr . From the analyses reported inthis paper, it appears that both components are undermassive (1.2+0.4M_ȯ), and that the secondary rotates not synchronously but morethan twice as fast. These conclusions follow from the analysis of (1)high-dispersion spectra near both quadrature phases, to which thesecondary contributes roughly 10% in the visual light, and (2)light-curves in the Stromgren and Walraven system covering the interval3200-5600 { Angstroms} and a time span of more than 2600 rotationalperiods. The light-curves show a very pronounced O'Connell effect, andonly marginal colour variations. Models assuming a temperature spoteither on the primary or the secondary explain the major part of theasymmetry in the light-curves, and are intended to provide usefulinitial estimates for more advanced mathematical codes. However, a morerealistic physical model will require more discriminatory data,including spectroscopic observations in other spectral windows, andspectroscopy over the whole orbital cycle. Based on observationsobtained at the European Southern Observatory (ESO), La Silla, Chile

A photoelectric investigation of light variability in AP stars
A study of the light variability of a number of peculiar A stars, mainlyin Stromgren colors u and v and in peculiarity index Delta-a, leads tothe proposal of the following light variability periods: (1) HD 5601,1.11 days; (2) HD 19712, 2.19 days; (3) HD 30849, 15.86 days; (4) HD38823, 8.64 days; (5) HD 53116, 11.98 or 18.10 days; (6) HD 56022, 0.92days; and (7) HD 81009, 33.97 days. In addition, evidence is given forvariability of HD 94660 on a time scale on the order of months or years,and it is shown that the rotation period proposed by Borra andLandstreet (1980) for HD 25267 is not supported by the light variationsobserved. The character of Delta-a variability is discussed.

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Observation and Astrometry data

Constellation:Peintre
Right ascension:04h54m33.45s
Declination:-52°31'25.1"
Apparent magnitude:8.07
Distance:127.714 parsecs
Proper motion RA:-16.4
Proper motion Dec:-13.5
B-T magnitude:8.345
V-T magnitude:8.093

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 31640
TYCHO-2 2000TYC 8510-418-1
USNO-A2.0USNO-A2 0300-01497186
HIPHIP 22818

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