Near-Earth Asteroid Monitoring
Beginning in Spring 2013, personnel and students have used the NIRo telescope to monitor small solar system objects classified as Near-Earth asteroids.
Under the auspices of the International Astronomical Union, the Minor Planet Center, housed at the Harvard-Smithsonian Center for Astrophysics, keeps track of all known asteroids and confirms newly discovered objects. An asteroid is considered to be a near-Earth asteroid (NEA) if its orbit brings it within 1.3 AU from the Sun at closest approach. (AU = astronomical unit = the average distance between Earth and the Sun = about 93 million miles or 150 million kilometers) The subset of NEAs that are larger than about 100 meters in diameter and whose orbits bring them within 0.05 AU of Earth’s orbit are classified as Potentially Hazardous Asteroids (PHAs). (For a sense of scale, the Moon is about 0.0025 AU from Earth on average.)
There are currently (Jan 2016) over 13,600 NEAs and over 1,650 PHAs that have been identified and confirmed. Even though some of these objects have been known and well studied for decades, there is a continual need for ongoing observations and new data. All the MPC can do is predict where these objects should be. Astronomers have gotten pretty good at doing that and their orbital predictions are very precise, at least for a little while. But as time goes on, the chance of small orbital deflections steadily increases, so there’s a continual call for new observations in order to keep the orbital predictions up to date and accurate.
In spring of 2013, NIRo submitted its first data to the MPC. These were positions of two very well known main-belt asteroids with very stable orbits. From, the quality and accuracy of these observations, the NIRo telescope at the Calumet Astronomy Center was given an official MPC observatory code (W11), with which to submit all subsequent observations. Since then we have made a total of 110 successful observations of 17 different NEAs (as of August 2016).
Can you spot the asteroid?
This is a composite, inverted image of ten one-minute observations taken on 05 Sep 2013 between 2:18 and 2:29 GMT. The near-Earth asteroid 1999 CF9 is visible in this field. (You can click on the image to view a much larger version of the image.) At the time this image was taken, 1999 CF9 was appoximately 0.158 AU (23.6 million kilometers) away from Earth.
1999 CF9 is a member of the Apollo group of asteroids, meaning its average orbit is larger than Earth’s, but its orbit is elliptical enough that it crosses inside Earth’s for a portion of its orbit around the Sun. It passes close enough to Earth’s orbit (0.019 AU) and is large enough (estimated at about 1.0 km in diameter) to be considered a PHA.
Eclipsing Binary systems (T Leo Minoris, Y Leonis, ER Vulpeculae)
There will soon be some informative and interesting material here on the work we’ve been doing to monitor primary eclipses of catalysmic variable stars, specficially Algol-type binaries. In particular, the Y Leonis system, which is interesting and unusual because the period of its orbit changes over time.
For more information on any of the NIRo projects, contact Prof. Adam Rengstorf.