The Leonid meteor shower takes place annually during practically the entire month of November, and this year it will have its peak on the night of the 17th to the 18th, when the number of shooting stars reaches its maximum.
Unlike other more famous meteor showers rich in shooting stars, such as the Perseids in August or the Geminids in December, the Leonids usually present a rather modest level of activity. However, there have been years in which this activity has increased substantially, providing impressive shows.
This year, the conditions for observing the Leonids are excellent since, on the night of the expected maximum, the Moon will be in a crescent phase for a few days and will set early, thus leaving a dark sky.
The so-called shooting stars (or meteors, in technical language) are traces of light that we can occasionally see on any night. In reality, these are tiny fragments of material that enter the Earth's atmosphere, coming from space, and disintegrate at altitude due to friction with the air.
The number of shooting stars that can be seen throughout the year is not always the same. There are specific days when the night sky seems to be filled with meteors. They are called meteor showers.
Meteor showers owe their existence to comets (and, in some cases, asteroids). These celestial bodies are very little compact and contain a large amount of ice formed by gases. When they approach the Sun and heat up, these ices vaporize and drag material from the rocky surface with them into space (which generates the tails of comets). In this way, the orbits of comets are filled with ejected material.
When our planet, in its movement around the Sun, crosses near the orbit of a comet, a large number of fragments detached from the object are found, many of which end up entering the atmosphere and being incinerated. For this reason, meteor showers take place regularly during the same days each year, precisely when the passage of our planet coincides with the orbit of a comet.
The object that feeds the Leonid meteor shower is comet 55P/Tempel-Tuttle, a 3.6 kilometer body that approaches the Sun approximately every 33 years, and was discovered by Wilhelm Tempel in December 1865. and confirmed by Horace Parnell Tuttle a few weeks later.
The rate of meteors produced by the Leonid shower is highly conditioned by the temporal proximity to one of the comet's close passes. These steps occur every 33 years (in line with the orbital period of 55P/Tempel-Tuttle), and it is then that the Earth encounters the most significant concentrations of the object's fragments.
The last time the comet approached was in 1998 and it will do so again in 2031. The passing of the year 1966 generated a true spectacle, since thousands of meteors per minute could be observed in a time frame that lasted only a quarter of hour. As NASA relates: “there were so many meteors that they seemed to fall like rain.”
Predicting whether a given meteor shower will be abundant in meteors is not an easy task. Due to small orbital variations, the Earth does not always traverse exactly the same region of space. Likewise, the fragments detached from comets usually disperse, occupying larger areas.
Although this year does not coincide with a close pass of comet 55P/Tempel-Tuttle, and although this meteor shower, under normal conditions, does not usually generate large rates of meteors (on the order of 15 shooting stars per hour), the conditions Observation points will be very good due to the absence of the Moon for most of the night, which will make it easier to observe the faintest meteors.
Additionally, the meteors from this meteor shower can be very spectacular due to the speed with which they cross the sky. Considered among the fastest, its fragments enter the Earth's atmosphere at 71 kilometers per second.
To be able to enjoy the meteor showers, it is advisable to move away from urban centers and look for places with dark skies. If this is not possible, the best option is to observe from elevated terraces, which leave most of the light from the streets below. In any case, an observation location should be chosen without too many obstacles, such as trees or nearby buildings, so that the largest possible region of sky can be seen.
Although meteors can appear anywhere in the sky, they all follow a path that appears to have started from a specific point in the sky. This origin, called radiant, corresponds to the place where the material left behind by the comet enters the atmosphere.
Each meteor shower has its characteristic radiant, and the region in which it is located in the sky gives its name to the event. Thus, the radiant of the Leonids is located in the constellation of Leo.
Viewing options improve when the radiant is high in the sky. Therefore, to contemplate the Leonids it is recommended to observe a few hours before dawn, when the constellation of Leo has already risen over the horizon. Furthermore, the Moon, which will be in its waxing phase, will set early (around 9:00 p.m., peninsular time, on the night of November 17) and, therefore, its light will not interfere with the observation of the phenomenon.
