This web page summarizes observations of the above NEO (suggested as the "parent" for the Chelyabinsk meteorite) using a Celestron 11-inch telescope at the Hereford Arizona Observatory in 2014.

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Data
downloads

2014 Apr28-May01 Tan
LCs

2014
April/May Gary LCs

2014
March Gary LCs

Error analysis

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**Data Download File: **

Gary data: Data for 2014 March & Apr/May by B
Gary

Tan
data: Data
for 2014 Apr28-May01 by TG Tan

**2014 April/May Gary
Observations**

Observations for Apr/May, 2014 are complete. Here's a light
curve for Apr/May showing Gary & Tan observations.

The asteroid was observed on 9 dates in early March, 2014. Below is a 3 sinusoid fit (in which periods for 2 sinusoids were fixed to be 1/2 and 1/3 of the free parameter period; all amplitudes and phases were free to vary). The largest amplitude periodicity was 63 hours, implying a rotation period of 126 hours.

Uncertainties are of four types:

1) Target asteroid stochastic

2) Reference stars stochastic

3) Reference stars systematic

4) Target asteroid systematics due to background stars

In each light curve I report the stochastic components for (1) and (2). These should be orthogonally added, along with ~ 0.020 mag which I assume is a reasonable SE for component (3), the set of APASS star mag's within a FOV. Finally, component (4) should be orthogonally added, but it is difficult to estimate because it depends on the density of background stars and the brightness of the asteroid. I recommend estimating component (4) by eyeballing the variation of average values in a LC with respect to the model fit trace. Every LC has the most obvious background star interference images removed from consideration, but there will be a residual variation due to those i didn't identify.

For example, in the LC for 2014.04.29, above, I estimate the SE variation of the averages to be 0.025 mag. The two stochastic components are 0.018 and 0.009 mag. All components to be orthogonally added are 0.018 (asteroid stochastic), 0.009 (reference stars stochastic), 0.020 (APASS systematics) and 0.025 (background star systematics) mag. Their orthogonal sum is 0.038 mag.

*This web page created 2014.04.29 by webmaster Bruce Gary*