Perseids

12 Aug

in Blog

STARS4ALL European project, in collaboration with the portal sky-live.tv, will broadcast the shooting stars from two Canary Islands Observatories. The STARS4ALL proposal also includes educational activities for students.

As every year, Perseids – also known as “St. Lawrence’sTears ” – reachesits peak of activity in mid-August. 2016 Perseid activity will occur between July 17 and August 24. The peakis expected between 13:00 and 15:30 UTC on August the 12th. In Europe, therefore, the nights between August 11st/12th and 12th/13th will be the best time for observation. The crescent moon will disappear in the second half of the night, so it will not be a problem to see a lot of meteors (on average one every two minutes) some of them very bright (due to its high-speed entry into the atmosphere ) if we are located in a dark place without light pollution and with clear horizons. According to Miquel Serra-Ricart, IAC astronomer, “Although the Perseids are not the most spectacular shower of the year, they never fail. Perseids are a safe bet.”

Image 1 – This image is a composition of several Perseids over Teide (Tenerife, Canary Islands). It was obtained on 2014 from images taken between 1h-4h UTC on August the 13th, 2014, from the Observatorio del Teide (Instituto de Astrofísica de Canarias, IAC), at the time of Perseids’ maximum activity. The images were shot following the movement of the stars, so the paths of the meteors show a convergence towards the top, where the radiant was. At the end, as a base, one of the images of the sequence with the Teide was included, where several walkers’ torches light the way up to Teide’s top. Observation M. Serra-Ricart, processing J.C. Casado-starryearth, IAC.

High Resolution.

A shower with history

Shooting stars are actually small dust particles of different sizes (some are smaller than grains of sand) detaching from comets or asteroids along their orbits around the sun. The resulting particle current (called meteoroids) is due to the melt produced by the solar heat and they are dispersed along the comet’s orbit that is crossed every year by Earth in its orbit around the sun. During this meeting, the dust particles disintegrate when entering the Earth’s atmosphere very fast, creating luminous streaks known as meteors.

Perseid activity, due to comet Swift-Tuttle discovered in 1862, is around 100 meteors / hour (ZHR or zenith hourly rates). In the years around the perihelion of Swift-Tuttle (its closest approach to the Sun, the last was in 1992 and the next in 2126) activity can increase to 400-500 meteors / hour due to the high density of meteoroids orbiting close to the comet. However, Perseids are known for their “bursts of activity” caused by the gravitational influence of the Solar System giants Jupiter and Saturn on the clouds of dust detached by the comet in the past. In 1839, the German observer E.Heis measured for the first time the maximum rate of the Perseids: 160 meteors / hour. Then, until 1858, it fluctuated between 37 and 88 meteors/hour. In 1920, Perseids rate was up to 200 meteors/hour and in 1983 it was 187. According to the Russian astronomer Mikhail Maslov next August Perseids activity could have an increase because of the “Jupiter effect”. The planet reached the maximum proximity to the orbit of Swift-Tuttle comet (257 million km) in November 2014. Meteoroids will need 22 months to reach the Earth. Will the rate rise in 2016?

Broadcast

STARS4ALL European project, in collaboration with the portal sky-live.tv, will broadcast the meteor shower live from Canarian observatories. The total time of the broadcast will be 30 minutes, separated into two events:

First event, August 12th 19:30-19:45 UT (21:30-21:45 CEST, 20:30-20:45 local).

Second event, August 12th 23:15-23:30 UT (13 agosto 1:15-1:30 CEST, 00:15-00:30 local).

STARS4ALL (stars4all.eu) is a H2020 Programme of the European Union, under Contract No. 688135. In STARS4ALL 8 institutions work (UPM , CEFRIEL , SOTON , NEC, ESCP Europe , IAC , IGB and UCM ) from 6 European countries. STARS4ALL’s aim is to raise awareness about the existence of light pollution in many of the places where we live and the importance of taking action to reduce it.

Image 2 – Perseid recorded by the AMOS-CI project on August the 7th 2015. In the picture we see a grazing meteor that occurs when the radiant (Perseus constellation in the case of Perseids) is close to the horizon. Meteoroids enter the upper atmosphere producing spectacular traces because of the friction.

Educational Events

1) Perseid activity calculation

SOMYCE (Sociedad de Observadores de Meteoros y Cometas de España) formulated an interesting proposal: calculate the activity of the Perseids from visual observations. All details on Perseids 2016 – Observation Campaign.

It is also possible to participate in the calculation of the meteor shower activity sending data to the International Meteor Organization (IMO, information).

2) Meteor height formation calculation

At the Canary Islands (IAC) observatories AMOS-CI project will conduct Perseids observations simultaneously from Tenerife (Observatorio del Teide) and La Palma (Observatorio del Roque de Los Muchachos). The observatories are around 150 kilometers away. Using this data it is possible to calculate the formation height and the orbits of the meteors per parallax.

Students are encouraged to use the same technique and apply it to last year Perseids and Geminids observations. Details are in the Teaching Activity “Height meteor formation calculation” at astroaula.net.