This feature often discussed meteor showers at the time of their scheduled appearance.

In general, meteor showers occur when comets, especially those returning after a few years, release dust particles from their nucleus as they pass through the inner solar system. These grains of dust never return to the comet, but continue to travel around the sun in the same orbit as the comet.

Over time, this dust spreads throughout the orbit of the comet. If, during its annual journey around the sun, the Earth encounters one of these dust flows, we see the dust particles entering the atmosphere at speeds of up to several kilometers per second and we vaporize in the form of streaks of light. friction with the atmosphere.

A handful of such showers is quite strong and can produce up to 60 or more meteors an hour, provided that the sky is not washed due to moonlight when the moon is almost full. Perseids showers in early August and Geminids in mid-December are two examples.

There are several small showers; one of them is the Orionid shower – so named because the meteors seem to come from the conspicuous Orion constellation – which is due to the dust of Halley's Comet and which produces up to 20 meteors per hour when it reaches its peak around October 21 of each year. . Unfortunately, this year, the moon is full on October 24th. So there may not be much to see Orionids.

For some meteor showers, the dust grains have not yet had time to spread throughout the orbit of the comet, but rather travel in broad tufts which, most often, are close to the comet ( usually behind this one). A classic example is the Leonid shower, which culminates every year around mid-November and is associated with the comet Tempel-Tuttle, which has a 33-year orbital period.

Normally, Leonids are a rather weak affair, producing no more than 10 meteors an hour, but they have sometimes been much more powerful than that. Tempel-Tuttle returned in 1965 and the following year, a huge meteor storm reaching 100,000 meteors per hour was visible from the western United States. Tempel-Tuttle came back again in 1998 and in the late 1990s and early 2000s, several heavy Leonid showers occurred.

Another bushy meteor shower is the Draconid shower, so named because the meteors seem to come from the Draco constellation, which is now high in our northwest sky during the evening hours, a little to the northwest of the bright star Vega. The draconids, which culminate in early October of each year, are associated with a comet called Giacobini-Zinner, which was first discovered in 1900 and whose orbital period is approximately 61 years and a half.

Although the shower is normally very weak, the Draconids are famous for producing powerful shows around the time Giacobini-Zinner made some of his returns.

In 1933, for example, a very heavy drastic rain with rates reaching briefly more than 10,000 meters per hour was observed in Europe. Two returns later, in 1946, despite the brilliant moonlight, another very strong shower was seen from the United States.

Although nothing has been so powerful since then, improved Draconid displays – with rates as low as a few hundred meteors per hour – have occurred in 1985, 1998, and 2011, all at about the same time. passage of Giacobini-Zinner. through the internal solar system.

Giacobini-Zinner is again crossing the inner solar system and was closer to the sun on September 10th; indeed, this feature discussed the comet a month ago. When it is at its brightest, Giacobini-Zinner can be detected with a pair of ordinary binoculars and is still easily detectable with small backyard telescopes, as it sails south along the Milky Way in winter in the constellation Monoceros, located east of Orion and above our horizon during the hours before dawn.

All this would suggest that we could potentially be in reserve for another strong draconian shower this year. Unfortunately, astronomers who study and model cometary dust streams have pointed out that the Earth did not seem to be near big bunches of comet dust this time, and that even the only cluster that could produce a moderate display – short of a few dozen meteors per hour – would take place during the day here in the United States

Nevertheless, the forecast of meteor showers is not an exact science, even though we have learned a lot about it over the last two or three decades. Indeed, surprises showers still happen from time to time. It would not hurt to check the Draconids this year, in case they have such a surprise in store for us.

Any draconian shower we could see will take place on Monday night, October 8th. It turns out that the moon is in its new phase that night, so the moonlight will not interfere in any way.

Will the Draconids succeed in presenting us with a sort of decent display, despite the contrary predictions? There is only one way to find out. . .

Alan Hale is a professional astronomer residing at Cloudcroft. Hale participates in various space-related research and education activities in New Mexico and elsewhere.

Read or share this story: https://www.alamogordonews.com/story/news/local/community/2018/10/13/halleys-comet-reaches-its-peak-around-oct-21-full-moon- blocks-our-view / 1551841002 /