The discovery of 2009 FV19 from Raheny observatory on March 21st was the third Irish asteroid discovery of 2009.   This discovery followed hot on the heels of the discovery of 2009 FM14 from Celbridge Observatory and 2009 EN1 from Raheny.

With the year hardly underway, its already been a vintage year for Irish asteroid discoveries following two similar discoveries (2008 TM9 and 2008 US3) in 2008.

On October 11th 2008, Dave Mc Donald (Celbridge Observatory) did something which hadn’t been done in 160 years.  Dave had, of course, discovered an asteroid.  2008 TM9 was in many respects unremarkable.  A main belt asteroid about 2km across may not inspire swashbuckling movie scripts.  However his discovery was described as ‘Monumental’ and ‘Historic’  The national media recognised the significance of this event and Dave found himself on the same newspaper page as Britney Spears and Angelina Jolie!!

We now move on to March 2009 and we now have a total of 6 asteroids discovered from Ireland.  The latest is a discovery of 2009 FV19 another main belt asteroid

Irish Asteroid Discoveries (1848 - 2009)

So lets look at the history of Irish asteroidal discovery from beginning to end. It started on April 25th 1848. Mr. Andrew Graham was observing at Markree Observatory (now sadly demolished) in Co.Sligo. Markree Observatory was owned by a Mr.Cooper but mostly operated by Mr. Graham. Graham discovered a ‘New Star in Ophiuchus’ and following due consideration proposed the name ‘Metis’ for his new ‘Planet’. This was the ninth asteroid to be discovered and is today officially known as ‘(9) Metis’. Of course we now know that Graham’s ‘Planet’ is in fact an ‘Asteroid’ or ‘Minor Planet’.

Sadly 160 passed before another asteroidal discovery. So it was with great excitement that we were able to announce the discovery of 2008 TM9. Within weeks of the discovery of 2008 TM9. This author announced the discovery of 2008 US3. Due to poor weather conditions an malfunctioning equipment there as a delay in proceedings before there was a second discovery from Raheny, 2009 EN1. This was followed by Dave McDonald’s second discovery of 2009 FM14 and finally on March 24th the IAU confirmed the designation 2009 FV19 from Raheny observatory. Certainly both myself and Dave McDonald are very excited by these discoveries. Indeed this is something we could have only dreamed of (and often did) a short couple of years ago.

So how exactly does one (or two) discover asteroids? Of course there is no magic formula to discovering unknown objects. However, you can stack the odds in your favour by carefully choosing the areas to search. Firstly avoid the areas which have been recently searched by the big surveys such as ‘LINEAR’, ‘Catalina’, ‘Spacewatch’ etc. These surveys employ large powerful telescopes to scan large areas of sky from very clear and dark locations. An amateur is unlikely to be successful in a ‘one-on-one’ with such a heavyweight. The ‘Minor Planet Centre’ (MPC) at Harvard university provides detailed information on where these large surveys have recently been searching. One of the most important part of this particular success story involves working as a team. This means that the team never searches the same area twice and as such doubles the area of sky searched. We also tend to steer well clear of the ecliptic where most main belt asteroids lie. This may at first appear counter intuitive but in fact, it decreases the number of previously known main belt asteroids which we detect and reduces the workload of sorting out which objects are already known and which are new. A given set of three images of an area are ‘blinked’ in sequence to highlight the movement of asteroids relative to the fixed stars. Once a candidate for discovery is detected software is employed to very precisely calculate the position of the new object on the CCD images taken. It is then necessary to submit a second night of observations before the IAU will award a designation (temporary name) to an object and declare a discovery.

Naming Our Irish Asteroids.

The procedure for naming asteroids often involves a wait of many years. Often up to a decade or more will pass before an asteroids orbit is known well enough that the IAU will assign a permanent number and name to it. We can speed up this process by finding earlier positions for our asteroids in online image archives such as that provided by the NEAT sky survey. Often we find our asteroids were photographed by these teams but never detected. We can then make these observations ourselves and forward them to the MPC for inclusion. This can greatly speed up the orbital determination and hence the naming. The discoverer of an asteroid is invited to propose a name for a numbered asteroid. If the proposed name is acceptable to the IAU it is then permanently assigned to that asteroid.

Hunting Near Earth Asteroids

All of the asteroids discovered from Ireland are typical ‘Main Belt’ asteroids. They orbit between the planets Mars and Jupiter and generally pose no threat of collision with our home world. However there are literally thousands of asteroids which are not so benign. ‘Near Earth Asteroids’ are objects whose orbit intersects that of our planet at some point Of these objects over 1,000 are considered a ‘Potentially Hazardous Asteroid’ (PHA). An asteroid is considered to by a PHA if its Minimum Orbit Intersection Distance (MOID) with respect to Earth is less than 0.05 AU and its diameter is at least 150 m (nearly 493 ft). These pose a very small risk of striking us at some point and as such require special monitoring. Raheny and Celbridge Observatories continue to provide positional data on these objects to the Minor Planet Centre and have been involved by means of confirming discoveries of this class of object. So the next time you see a big screen blockbuster movie involving asteroids and thermonuclear devices remember that Ireland is doing its part to ensure that such a scenario is at least known well enough in advance to be able to provide a more ‘considered’ solution.

Hopefully 2009 will see some more asteroid discoveries by the Irish team and maybe we will even see the first ever NEA or PHA discovered from Irish soil.