Thursday, June 2, 2022

Experience the numerous meteor showers in June

For those who are new to astronomy we remind some useful definitions to understand the phenomenon in question: by meteor shower we mean the fall of a large number of meteors that seem to come from a single point called radiant. The phenomenon is linked to the fact that our planet in its orbit around the Sun passes through areas of small debris and dust, remnants of comets that approaching our sublimate star. These are very small rock fragments (they can be as large as a grain of sand or as a boulder) known as meteoroids.

 When these objects come into contact with our atmosphere, they burn, creating light trails that often catch our attention: in this case, meteors. A meteor that survives its descent through the atmosphere and hits the ground is called a meteorite.  Each swarm is characterized by a value ZHR, Zenithal Hourly Rate that indicates the number of meteors that would be observed in an hour, under a dark sky if its radiant was at its zenith.


The swarm that will be the master this month is that of the Arietidi active from May 22 to July 2, with peak on June 7 and radiant located in the constellation of Aries. It’s a strong swarm with a ZHR of 60, although the proximity of the radiant to the Sun makes it very difficult to see the meteors; also the maximum visibility is just before dawn.


The origin of this swarm is believed to be the asteroid 1566 Icarus. 


The 9 June reaches its peak the meteor shower of the Zeta Perseids that like the Arietids has the radiant prospectively close to the Sun therefore it is a diurnal swarm not visible but can be captured radioastronomically. At the origin of the swarm there is the comet of Encke, 2P/Encke, one of the 4 comets that bear the name of those who predicted and studied the period rather than that of those who discovered them. It is thought to be part of a larger comet that split in the Bronze Age causing a crater in Iraq currently "occupied" by Lake Umm.


June will also be characterized by two irregular swarms and with variable ZHR: the first is that of the Tau Hercules originated by the periodic comet 73P/Schwassmann-Wachmann that is continuing to disintegrate and that probably will lead in a few years to admire a medium-sized swarmstrong seen the increase of debris that is noticed from year to year; the second is that of the Bootids of June that derive from comet 7P/ Pons-Winnecke. 


They are considered irregular because over the years they have undergone changes in ZHR from 1-2 meteors per hour up to even 20 in a not constant way; swarms are very difficult to study and for which only time will help us find the answers. 


The Tau Hercules have the radiant in the constellation of Hercules and the peak localized between the 3-4 June; the Bootidi of June instead have the radiant in the constellation of Boote and the peak on the 28 of the month.


Among the swarms of the month we also point out the weak Gamma Dolphins, Beta Taurids and Andromedids of June.


The Gamma Delphinids (not to be confused with those of January) are probably originated from the comet C/2006 VZ13 LINEAR and are active from 1 to 20 June with a peak on the 11th of the month, with variable and radiant ZHR in the constellation of the Dolphin.


The Beta Taurids have the radiant in the constellation of Taurus but prospectively close to the Sun therefore also in this case we are in presence of a diurnal swarm in activity between June 5 and July 18 and peak on the 29th of the month, day when thanks to radio observations, register a ZHR of 25.


The June Andromedids are active from 10 to 14 June with a peak on 12-13 days and have the radiant in the constellation of Andromeda; they derive from the non-periodic comet C/1983 J1 Sugano-Saigusa-Fujikawa. 

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