NASA regularly sends space probes hundreds of millions of kilometers from Earth to study comets – ice “aliens” from the outer region of the solar system. There is another way to observe some of them: in 2017 and in 2018 3 comets – 41P, 45P and 46P – will fly past our planet, and they can be seen in a normal telescope.
The comet is one of the most interesting celestial bodies in the solar system. To date, more than 400 short-period comets have been detected. The comet is called short-period if it makes a complete revolution around the Sun for a period of up to 200 years.
A comet usually consists of a nucleus, a coma and a tail. The core – a solid part of the celestial body, in which almost all of its mass is concentrated – resembles a dirty snowball because it consists of a mixture of ice with an interspersion of meteoric matter. The nucleus is surrounded by a coma, or a light misty shell of gases and dust that stretches 100,000 to 1.4 million kilometers from the nucleus. When approaching the Sun, jets of gas and dust form long tails that can be seen from the Earth if the celestial body flies close enough to our planet.
In total, in 2017 and in 2018, 3 short-period comets will fly past the Earth. Throughout the world, astronomers have set up telescopes to study the structure and chemical composition of each celestial body.
“This provides a good opportunity to engage in astronomy without resorting to the launch of a spacecraft,” said Kelly Fast, head of the NASA headquarters near-Earth objects monitoring program.
Since the comets can be observed even with a simple field telescope (and some – even with the naked eye!), The researchers hope for the help of amateur astronomers.
“Amateur astronomers can help us watch comets without interruption,” explains astronomer Tony Farham of the University of Maryland in the United States. “We can combine the efforts of amateurs and professionals to study coma. A few years ago we already watched the ISON comet so much, and this experience was very successful: we received data from 23 different research groups around the world. ”
“Popular mechanics” decided to consider in detail each of the comets that have already flown or will fly by in the next year.
Comet 41P / Tuttle – Jacobini – Kresaka
A short-period comet of the Jupiter family. For the first time it was discovered by American astronomer Horace Tuttle in 1858, and then the Frenchman Michelle Jacobini and Slovak Lubom Kresak independently rediscovered in 1907 and 1951 respectively.
In 2017, the comet flew past Earth for the 11th time after its discovery. April 5, its minimum distance from our planet was 22 million kilometers, and on April 13 the celestial body passed its perihelion (that is, the shortest distance from the Sun).
41P could be observed using an ordinary field telescope in the constellation of the Dragon between the Great and Little Dipper. Now the comet moves away, but until the end of May it can still be seen through the telescope.
Comet 45P / Honda – Murcos – Paidushakova
In 1948, the comet was independently discovered by three astronomers: a Japanese Minoru Honda, a Czech Antonin Murkos and a Slovak Ludmila Paidushakova.
The astronomers managed to observe the heavenly body in all its returns, except 1959. In 1995, the brightness of the comet was the most noticeable and reached 6.5 magnitude.
In February 2017, the comet again could be observed in the night sky – its distance from the Earth was only 12 million km. The heavenly body could be seen in a small amateur telescope or even binoculars. At the same time, the radio telescope of the Arecibo Observatory received the first radar images of Comet 45P. Astronomers have found out that the size of the core of the celestial body is almost 1.3 km along the largest axis, while the comet itself has a bipartite form.
Comet 46P / Virtanen
The heavenly body belongs to the family of Jupiter and has a period of 5.4 years. The comet was discovered by the American astronomer Carl Virtanen in 1948: he photographed it in the Lika Observatory.
The comet planned to launch the Rosetta spacecraft, but because of technical problems the mission was postponed, and the ship was soon launched to the comet 67P / Churyumov-Gerasimenko.
In December 2018, the comet will approach the Earth at a distance of 11.5 million km. The most interesting thing is that at this time in a dark clear sky it can be seen with the naked eye.
“The 46P has a small core, but it is also known as a” hyperactive “comet,” says astronomer Tony Farham of the University of Maryland in the United States. “We believe that it throws ice crystals from the surface, and this gives more activity.”