Posts Tagged ‘Binary asteroids’
Since the beginning of the work at our observatory, one of our basic tasks has been the job of photometric studies of near Earth asteroids (NEAs). At the end of October observations were made of several bright asteroids, including asteroid 3122 Florence which our team has been observing since Summer at several observatories. The asteroid belongs to the Amor group like the first NEA we discovered, 2010 RN80, and is potentially hazardous to our planet (Potentially Hazardous Asteroid, PHA). The period of the asteroid is already precisely known; it is 2.3581 hours. In the graph at left you can see its phase curve from observations obtained October 28-29 at our observatory.
Our main task is the determination of the angle of its rotation axis and, of course, searching for possible satellites. For that it is necessary to determine a second or even third period within the basic one, all tied to the rotation of the main body. For this painstaking work, high precision photometric observations are needed at various phase angles at several oppositions. This is not a task for one year.
Photometry of asteroids is more complex than observing variable stars, as the asteroids move quickly in space, especially near Earth asteroids. Because of that, from night to night, observations are made using different comparison stars, which complicates the task. It is also necessary to calculate the phase angle. Brightness curves obtained on different nights will slightly differ one from another, and to determine a phase curve, it is necessary to take out the brightness differences associated with the spatial effect (distance from the observer, phase angle), but not the rotation of the asteroid on its axis, as well as the possible orbital motion of a satellite.
Here you can become acquainted with the paper about the discovery of the satellite of asteroid 8373 Stephengould.
More detail information about our photometry program you can find on this page.