Geminid swarm maximum and comet 46p/Wirtanen
The coming weekend promises to be extremely promising in terms of attractions in the night sky. The Geminid swarm will reach its maximum today, and on Sunday comet 46P/Wirtanen will approach Earth and, weather conditions permitting, it will be possible to see it with the naked eye.
Rój Geminidów is one of the most active swarmsów meteorów. Meteoroids falling into the Earth’s atmosphere are not the remains of a comet, as in most casesóin the swarm ofóin a meteoriteów. Their parent body is the asteroid 3200 Phaethon. It takes its name from the mythical hero Phaeton, son of the Sun god – Helios, który lost control of his father’s stolen chariot and almost set the Earth on fire.
Earth passes through a cloud of debris scattered by 3200 Phaethon every December. Geminid swarm maximumów falls on December 13-14. In the most active years rój Geminidów delivered up to 120 „of falling stars” per hour. Meteoroids enter the Earth’s atmosphere at a speed of 35 kilometersóin per second.
The swarm’s parent asteroid, 3200 Phaethon, was discovered in 1983 and is about five kilometers in diameteróin diameter. The perihelion of its orbit is close to the Earth’s orbit, which causes a potential danger of collision. It approaches the Sun at a very short distance, causing its surface to heat up to 1500 Kelvinów. This causes stresses in the surface of the object and the formation of a dust pigtail, któwhich we later see in the form of Geminidsów. For this reason, the object is sometimes called „rocky comet”.
Interestingly, before 1830 there is no mention of Geminid sightingsów. The first zwróThe Belgian astronomer pointed out A. Quetelet, whichóry on the night of December 12-13, 1830 recorded 40 meteorsów. Swarm activity has increased by 20 percent in the past 17 years. The maximum of the swarm is wide enough for us to observe it for two days, and the r itselfój is good for observations from Polish latitudes. Rój should be clearly visible by December 17.
First „falling stars” can already be viewed krótko after sunset, although there will be more of them every hour. The best spectacle with a lot of meteorsów falls on Friday just before sunrise. The moon is just before the first quarter, so it should not hinder observation. The problem may be the temperatures, whichóre not encouraging outdoor observations. The spectacle can also be spoiled by the weather. A prerequisite for seeing anything is a cloudless sky, and that can be hard to come by.
For observation, it is best to choose a dark place, away from the city. Radiant – place in the sky, from whichórego arriving meteors, is located near the constellation of the Twins. It is therefore necessary to look to the eastern horizon.
The biggest highlight of the month in the night sky is comet 46p/Wirtanen. It was discovered in 1948. Usually the comet is too far away to be freely viewed from Earth, but this year it has the closest approach in 70 years. On Sunday, December 16, it will be at a distance of 11.6 millionóin a kilometerów.
The comet belongs to a large, more than 400 objectów, comets of Jupiter’s family. They remain under the strong influence of the gas giant’s gravity, hence their name. 46p/Wirtanen is a small object. It is a little over a kilometer in diameter and does not leave behind a long braid. This is one of the few comets thatóre are (sometimes) visible to the naked eye – they then become bright enough, like the faint star.
At its closest approach, the comet should be visible to the unaided eye. Although, as is the case with comets, they are unpredictable. As David H once said. Levy, wspóhe discovery of comet Shoemaker-Levy 9, whichóra in 1994 hit Jupiter, „Comets are like cats: they have tails and do what they want".
Of course, as in the case of the meteor swarmów, observations are best made outside urban areas. You can also use binoculars to increase your chances of seeing the comet.
46p/Wirtanen should be light green in color. This is because of the comet’s composition. The object contains a lot of cyan, whichóry glows green when ionized by sunlight. It should be looked out over the southern horizon.