Tuesday, December 22, 2009

My first discoveries, in 2009

Asteroid 2009 YW6 (333744)

The Minor Planet Center (MPC) has assigned on December 21, 2009 a new discovery. The asteroid 2009 YW6 (333744) was discovered in images taken on December 20 and confirmed by Antonio Garrigós (MPC B37) and the author in new observations the night after. 

Image of discovery. Note that the asteroid is on the edge of the field

Discovery of the Apollo PHA asteroid 2009 ST19

This minor planet, belonging to the Apollo class, is also flagged as a "Potentially Hazardous Asteroid (PHA)", an object that, because of its orbital parameters, might represent a possible threat of impact for planet Earth (http://neo.jpl.nasa.gov/neo/pha.html).

It has beeen discovered by the Spanish amateur astronomer Josep M. Bosch from Santa Maria de Montmagastrell (MPC B74) on 2009, Sept. 16.2, ay magnitude about 17. At that time it was posted on the NEOCP webpage of the Minor Planet Center as "jmbo11"; after a couple of days it was withdrawn, because it was not confirmed by any further observations.
On 2009, Sept. 22, the LINEAR sky survey picked-up a fast moving object, that was posted in the NEO-Cp as "BQ24981". After some follow-up observations from various sites, on 2009 Sept. 23 the MPC published M.P.E.C. 2009-S72 (http://tinyurl.com/yer5xmr), informing that the two objects mentioned before were actually the same celestial body.
According to the NEODyS webpage this object. about 1.5 Km in diameter, made a close pass to Earth on 1980, Oct. 4, at a minimum possible distance of about 0.009 AU (nominal distance of about 0.04 AU).

Diagram by Berndhard Häusler

Observatory Santa Maria On September 23th, at 10:00 pm. I went on a motorcycle to my observatory, located in a small village of 60 inhabitants called Santa Maria de Montmagastrell, 8 km far from my house. As I walked out of the fuel station, my mobile phone started to rang. At the time, I stopped the bike and went back to the side of the road, the phone stopped calling. Upon arrival at the observatory, the call repeated while preparing the telescope for another observation night. This time, I can answer the call phone. It was Gustavo Muller to communicate that the MPC have just provisionally designated the possible NEO I saw in some pictures taken last September 16. That past day, I had gotten up at three in the morning and, among other objectives, Comet 137P looked to no avail. Well, the comet was not in the 14 pictures I took of the field and so I went to other objectives that had to watch. At dawn, with the first light was fading I control systems and the telescope placed in sleep mode to close the observatory and go to bed to rest. At that time, I reviewed the images of the comet 137P field by the custom of not leaving any possibility loose. I started the blink of images and in less than a second I realized that there in the fourteen shots 70 seconds each moving something big. I checked that was not a known object, and then I sent four astrometric measurements to the MPC. Hours passed, spent six days, and when he had lost hope of recovering the object the MPC announced it had been found by various observatories, including the LINEAR and gave the provisional number 2009 ST19. I thought I had lost, although the night I had a discovery following email exchange with Tim Spahr of the MPC, who assured me find it. And they've found!

Richard Miles said:
Yes, Special congratulations, José María. This is a very special object. It breaks the record in terms of the closest pass by an object of this size, about 1 km across! 
We currently know of no object larger than this to have come closer than this object has recently. The next largest such object was the famous (69230) Hermes (H=17.5), which approached to 0.0050 AU of the Earth in 1937! Your PHA, 2009 ST19 will be visible during the next few weeks and so will be a good target for photometry.
Richard Miles
Asteroids and Remote Planets Section
British Astronomical Association

Orbit diagram update: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009%20ST19;orb=1

I dedicate this discovery to the Departament d'Educació de la Generalitat de Catalunya and the educational community of Catalonia, to which I belong.

The best image of Asteroid Apollo 2009 ST19 by the discoverer on September 26, 2009

2009 ST19 in NEODyS
Number of crossings per revolution
                Venus Earth Mars Jupiter Saturn
Crossings    0        4       4       0        0
Close approaches from 1950 to 2100
Planet     Date                Min possible distance
EARTH 1980/07/13.15029 0.0097665
EARTH 2009/08/31.09278 0.0647428
EARTH 2038/09/22.26839 0.0104962
EARTH 2067/09/01.69748 0.0124637

List of Apollos:

Observations for all Near Earth Asteroids
Observations and residuals
NEODyS provides informationnd services for all Near Earth Asteroids from B74
The NEO Confirmation Page