Bright Oronid on October 21st, 2014

oronida2The Orionids are caused by little Comet Halley detached fragments (meteoroids), along its orbit around the Sun. Most of these meteoroids are small particles with a size of a grain of sand, and impact against the Earth atmosphere with a speed of about 230.000 Km/h. The maximum activity of this meteor shower happens between October 21st and 22nd, when about 25 meteors can be seen each hour, although some years this activity is even bigger. Some of the detached Halley Comet fragments have a diameter of 1 cm or more, and these are the ones producing bright fireballs that, in some cases, can compete with the full moon brightness. 


Devices installed at Calar Alto can register the emission spectrum of these fireballs, which allows analyzing these cometary fragments chemical composition, and know the meteoric plasma column temperature that happens within the atmosphere during the disintegration of the metoroid. Thus, from the emission spectrum (see the right picture) of the Orionid that took place on October 21st 2014, the temperature of such plasma was determined, and results to be about 5100 ºC. 

Below you have a couple of videos showing the sequence. First is at a normal speed. Second one is half the normal speed, so you can better appreciate the fireball (bottom right hand of the screen)

 Normal speed: 

 Half speed: