We present V-band photometry of the 20000 brightest asteroids using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) between 2012 and 2018. We were able to apply the convex inversion method to more than 5000 asteroids with more than 60 good measurements in order to derive their sidereal rotation periods, spin axis orientations, and shape models. We derive unique spin state and shape solutions for 760 asteroids, including 163 new determinations. This corresponds to a success rate of about 15%, which is significantly higher than the success rate previously achieved using photometry from surveys. We derive the first sidereal rotation periods for additional 69 asteroids. We find good agreement in spin periods and pole orientations for objects with prior solutions. We obtain a statistical sample of asteroid physical properties that is sufficient for the detection of several previously known trends, such as the underrepresentation of slow rotators in current databases, and the anisotropic distribution of spin orientations driven by the nongravitational forces. We also investigate the dependence of spin orientations on the rotation period. Since 2018, ASAS-SNhas been observing the sky with higher cadence and a deeper limiting magnitude, which will lead to many more new solutions in just a few years.
We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14d, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light-curve analysis lead to absolute masses and radii of M1=1.5439+/-0.0098M_{sun}_^N^ and R1=1.536+/-0.018R_{sun}_^N^ for the primary, and M2=1.2196+/-0.0080M_{sun}_^N^ and R2=1.151+/-0.029R_{sun}_^N^ for the secondary. The effective temperatures are 7270+/-150K and 6260+/-180K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MESA Isochrones and Stellar Tracks series shows excellent agreement with these determinations, for a composition of [Fe/H]=+0.08 and an age of 350Myr. The two components of BT Vul are very near the zero-age main sequence.
We present new photometric observations in Johnson V and B of WR30a, revealing relative dramatic changes in brightness of 0.2mag. These variations occur on a time scale of hours, and are only seen in V. We argue that they are not caused by dust extinction, but either by a dramatic change in the strength of the C IV 5801-12{AA} emission line doublet due to a de-excitation process, or by some unknown continuum effect.
We report measurement of the trigonometric parallax of W51 Main/South using the Very Long Baseline Array. We measure a value of 0.185+/-0.010mas corresponding to a distance of 5.41^+0.31^_-0.28_kpc. W51 Main/South is a well-known massive star-forming region near the tangent point of the Sagittarius spiral arm of the Milky Way. Our distance to W51 yields an estimate of the distance to the Galactic center of R_0_=8.3+/-0.46(statistical)+/-1.0(systematic)kpc by simple geometry. Combining the parallax and proper motion measurements for W51, we obtained the full-space motion of this massive star-forming region. We find W51 is in a nearly circular orbit about the Galactic center. The H_2_O masers used for our parallax measurements trace four powerful bipolar outflows within a 0.4pc size region, some of which are associated with dusty molecular hot cores and/or hyper- or ultra-compact HII regions.
The photoelectric observations in v and b bands for YY Eri are presented. These observations were obtained during four nights in November, 1984, with the 35-cm Cassegrain reflector of the Yunnan Observatory in China.
TT Ari was observed in the 5 passbands VBLUW (544, 430, 384, 362 and 324nm) during 3 nights on the 90cm telescope at ESO (La Silla), between July and November 1988, with an integration time of 16s.
VBLUW photometric observations of 13 eclipsing binary stars carried out by C.J. van Houten with the Walraven 5-color photometer between 1965 and 1978 are presented together with a first analysis of the orbital periods.
The 1982-1985 photometry (VBLUW system) of the O3V+O8V close binary HD 93205 has been rediscussed because of new insights into its true nature and orbital changes. By comparing this data set with the one obtained by Antokhina et al. (2000ApJ...529..463A) in 1993, and using the same ephemeris to construct the light curve in the phase diagram, the effect of the apsidal motion became obvious: a phase shift between the two light curves and a small change of the shape. A phase-locked light variation in the L passband (containing the higher Balmer lines) is clearly present in the 1982-1985 data set and is presumably due to absorption if the O8 star is seen through cooler inter-binary gas, e.g. the bow-shock between the two colliding winds.
We have obtained photometric observations in a 182arcmin^2 area, 25' to the north of the center of the globular cluster {omega} Centauri. The Stroemgren vby and broadband BI filters were used to obtain measurements for some 2500 stars. Preliminary examinations of parts of the data have been presented previously (Hughes & Wallerstein, 2000, Cat. <J/AJ/119/1225>; Hughes, Wallerstein, & van Leeuwen, 2002, in ASP Conf. Ser. 265, 73). Here we present the complete data set, study the giant branches, and use the B-I color index as a tool for assessing the ages of the populations within {omega} Cen.
