Astrometric and photometric studies of the 2009 WZ104 asteroid as it approached the earth

Abstract

The astrometric and photometric observations of the potentially hazardous 2009 WZ104 asteroid were carried out at the MTM 500M and ZA 320M automatic telescopes of the Pulkovo Observatory in December 2009. A total of 686 observations were performed in the integral band and 146 observations with B, V, R, and I filters on an arc of the orbit of 17°; these accounted for about 77% of all worldwide observations (http://www.minorplanetcenter.org/iau/ECS/MPCOBS/MPCOBS.html).On the basis of the obtained data, the orbit was improved and an estimation of the physical parameters of the asteroid was made. Estimates of the absolute stellar magnitude of the asteroid, H = (20.52 ± 0.04) m , as well as its size and mass, were obtained. The taxonomic class of the 2009 WZ104 asteroid (R or Q) was determined. A frequency analysis of the series of observations was carried out; periodicities in the asteroid's light variation were revealed using this method.

Detection of large color variation in the potentially hazardous asteroid (297274) 1996 SK

“…The possible implication will be discussed later. (Betzler et al 2010;Carbognani 2008;Dandy et al 2003;Hapke 2000;Hergenrother et al 2009;Hicks et al 2011aHicks et al ,b, 2012aHicks & Dombroski 2012;Hicks et al 2013a,b;Jewitt & Hsieh 2006;Jewitt 2013;Karashevich et al 2012;Pieters et al 2000;Ye 2011).…”

“…The long axis and the short axis can be computed to be 1.57 km and 1.05 km, respectively. Carbognani, 2008;Dandy et al, 2003;Hapke, 2000;Hergenrother et al, 2009;Hicks et al, 2011Hicks et al, , 2012Hicks et al, , 2013Jewitt et al, 2006Jewitt et al, , 2013Karashevich et al, 2012;Pieters et al, 2000;Ye, 2011. )…”

“…Table 3 summarizes Carbognani, 2008;Dandy et al, 2003;Hapke, 2000;Hergenrother et al, 2009;Hicks et al, 2011Hicks et al, , 2012Hicks et al, , 2013Jewitt et al, 2006Jewitt et al, , 2013Karashevich et al, 2012;Pieters et al, 2000;Ye, 2011.) 3 and Figure 6) similar to shape of Q-type asteroids while still having significant differences from those taken at other times. The possible implication will be discussed later.…”

“…Fig.4The color-color diagram of NEAs with known color indices in different taxonomic types [α] and (297274) 1996 SK observed from this work. α means all references listed below(Betzler et al 2010;Carbognani 2008; Dandy et al 2003;Hapke 2000;Hergenrother et al 2009;Hicks et al 2011a Hicks et al ,b, 2012aHicks & Dombroski 2012; Hicks et al 2013a,b;Jewitt & Hsieh 2006;Jewitt 2013;Karashevich et al 2012;Pieters et al 2000;Ye 2011). …”