UBV photometry of 262 southern galaxies

Multi-aperture photometry of 262 bright southern galaxies in the JohnsonUBV system is given. Most of these are south of =–30°, although some northward to =–10° are included. A total of 169 objects have published radial velocity determinations. These provide distances, and enable construction of colour-magnitude diagrams for this subset of bbjects through a physical diameter of 2.0 kpc (withH _o=100). The two-colour diagrams for the inner regions of the galaxies differ from those of integrated galaxies due to the colour changes towards their centres. Comparison with theoretical models of Larson and Tinsley (1978) suggest that the colours of the inner portions of most ellipticals and lenticulars are consistent with their having all stars formed at nearly one epoch with little subsequent star formation, while for spirals larger amounts of star formation, either in bursts or continuously, are suggested. This simple picture is complicated by the presence of certain objects having peculiar colours indicative of large amounts of recent star formation.     

UBV photometry of Seyfert galaxies. I. MCG 8-11-11 and Markaryan 6

P. K. Shternberg State Astronomical Institute. Translated from Astrofizika, Vol. 28, No. 1, pp. 5–17, January–February, 1988.     

UBV photometry of Seyfert galaxies. II. NGC 6814

P. K. Shternberg State Astronomical Institute. Translated from Astrofizika, Vol. 28, No. 2, pp. 233–242, March–April, 1988.     

UBV photometry of Vesta

A lightcurve of Vesta, obtained on four nights between June 23 and 30 June 1978 during the coordinated campaign for the determination of the rotation period, is presented. The observations were performed at the 91-cm telescope of the Catania Observatory employing UBV filters and a photon counting photometer. The V lightcurve apparently shows a single maximum, suggesting that the 5^h20^m29^s.2 period is the correct one. Features are evident near the maximum and the minimum closely resembling those of Johnson's lightcurve of 22 December 1950 and Taylor's of January 21, 1973. The amplitude in V light is 0^m.105 and small variations are also found in the color indices. The largest color variation is for the U-V with Δm = 0.^m.05, which is slightly larger than the value 0^m.02 found by T. Gehrels [Astron. J.72, 929 (1967)]. The maximum and minimum values occur at the same phase with respect to the maximum V light as found by Gehrels, i.e., Vesta appears bluer near 0^p.25 and redder near 0^p.7. Corrections with the solar phase angle were made using the coefficients given by Gehrels for the B-V and U-V while a new value of 0.036 mag/deg was assumed for the V observations. The available amplitudes of Vesta's lightcurve were analyzed with respect to the longitude position and the solar phase angle.     

UBV photometry of Triton

UBV measurements of Triton relative to Neptune were obtained with an area-scanning photometer on 11 nights during the 1977 apparition. Observed orbital brightness variation shows that Triton is locked in synchronous rotation around Neptune. Its leading side, seen at greatest western elongation, is found to be 0.06 mag brighter than its trailing hemisphere.     

UBV photometry of RT Persei

Photoelectric and absolute elements of the system RT Per have been determined inU, B, andV filters. It is suggested that the primary star may be surrounded by a gaseous disk.     

UBV photometry of FK Comae

UBV photometry of the peculiar star FK Comae, obtained during the period January–June 1983, is presented. The amplitude of the photometric variation has raised with respect to the previous observations performed in 1981 and 1982, attaining about 0.18 mag in theV filter. Colour curves indicate that the star is redder at minimum light; this fact is consistent with both the models presented to explain the properties of FK Comae. A Fourier analysis of the light curves available in the literature has been performed; the phases of minimum and maximum light turn out to be noticeably stable in time. This fact is difficult to be reconciled with the hypothesis of dark spots that are observed to migrate in other active stars. Rather, it could be explained by the model of Walter and Basri (1982a, b), implying an extremely evolved Algol-type system accreting mass on its primary component.     

UBV photometry of HR 1176

We present photoelectricUBV observations of the suspected Caii emission line star HR 1176. A period analysis of the observations by using the method of Shell-Metzner failed to yield any true period which is probably due to (i) the large gaps in the observations, (ii) low-amplitude variation, and (iii) the nonconstancy of the period, or there may be no regular light variation. A visual inspection of the present observations shows no systematic or abrupt variability except some scatter. However, a long period eclipsing nature of HR 1176 cannot be ruled out by this observations.     

UBV photometry of BX andromedae

The UBV observations of a marginal contact system BX And obtained during 1987, 1989 and 1990 seasons at the Ankara University Observatory are presented. Based on all available light curves of the system we studied light curve variations, particularly at the extrema points. Time scale of the variations was found as short as a few cycles of the orbital revolution. Six new estimates of the minima times are given. Some indications are found that the system might be detached or semi-detached.     

UBV photometry of AW Pegasi

NewUBV observations of the classical Algol system AW Peg were presented. The photometric minima times were collected and used together with the new determinations in a period study. No sign of any period change was found from observations covering more than sixty years. TheB andV light curves are analyzed by means of the Wilson-Devinney approach. It was verified that the system is semi-detached with a Roche lobe filling secondary.     

UBV photometry of ER Vulpeculae

UBV photometry of RS CVn-type eclipsing binary system ER Vulpeculae has been presented. The period comes out to be 0 _. ^d 698093. The average depths of primary and secondary minima are, respectively, 0 _. ^m 21 and 0 _. ^m 12. The colours at various phases have been given. A dip is seen around phase 0 _. ^p 73 as was seen in the observations of Arevaloet al. (1988). Large scatter is present in the observations as noticed earlier, and may be due to activity of the components.     

UBV photometry of DX Aquarii

U, B, V photometry of the eclipsing binary DX Aqr has been presented for the first time. The period of the system comes out to be nearly half the period given by Strohmeier (1966) and a value of O^d.472502 has been determined. The colour of the system has been discussed. The primary eclipse is a total occulation. The orbit seems to be eccentric. The system belongs to Algol type. DX Aqr may be a very complicated system. The present results are considerably different from those of earlier investigations.     

UBV photometry of galaxies in groups and their neighborhood. the Geller-Huchra group GH 3

Byurakan Astrophysical Observatory. Translated from Astrofizika, Vol. 36, No. 3, pp. 315–332, July–September, 1993.