comets

comets

Astronomers have discovered a new comet, which may become the brightest comet of the decade

Comet C/2012 S1

Comet C/2012 S1

 

C/2012 S1 (ISON) – Four Russian comet was discovered by Vitaly Nevsky (Belarus) and Artem Novichonok (Russia), September 21, 2012 at the observatory ISON-Kislovodsk, international scientific network of optical instruments (ISON), located near Kislovodsk. Cometary nature of the object has been confirmed in several large telescopes, the first of which was a 1.5-meter telescope Maidanak Observatory (Observer O. Burhonov).

During the refinement of the orbit by many observatories around the world, managed to find the so-called preotkrytie (prediscovery) – found that this object has already been observed for one night December 28, 2011 and January 28, 2012, at the observatories Mt. Lemmon and the Pan-STARRS 1, respectively. As a result, the total arc of observations has increased many times and now we can say with certainty about the orbit of the new comet.

Perihelion, ie the closest point to the Sun, the comet should be held in late November 2013, at a distance, a little more than 0.01 AU! If the comet is destroyed on the approach, as it has been with the comet C/2010 X1 (Elenin), we are waiting, perhaps the brightest comet decade, which would eclipse the comet C/2011 L4 (PAN-STARRS).

Currently the comet is still beyond the orbit of Jupiter and is about 18 gloss magnitude.

Amateur astronomer discovered a new comet

Amateur astronomer discovered a new comet

Greenish spots in the center of the picture – Comet C/2012 C2 (Bruenjes). Photos Fred Bruenjes

Amateur astronomer Fred Brunhes discovered a comet in the night of February 10, 2012 with a 14-inch telescope Meade LX200GPS. After collecting and sending all the data to the Minor Planet Center, which is located at the Smithsonian Astrophysical Observatory, the comet was given index C/2012 C2 (Bruenjes).

Currently the comet C/2012 C2 is located about 0.555 AU from Earth. Its exact size and orbital period is not yet known. You can see the comet with a telescope in the northern hemisphere, as the object of 16.6 magnitude in the constellation Aries.

comet Lovejoy

comet Lovejoy

 

Comet Lovejoy (C/2011 W3), also known as the “Christmas Comet”, was opened November 27, 2011 by an amateur astronomer Terry Lovejoy. Interesting comet that was very bright, and is classified as “scratching” the Sun family comets Creutz, the first in many years, the near-solar comet, seen in the way the sun from the Earth observer, not Space Observatory observations of the Sun, such as SOHO and STEREO.

In addition, the calculations showed that the December 16, 2011 C/2011 W3 comes closer to the Sun at a distance of only 140 thousand kilometers from its surface, which is 100 times shorter than the distance between the Sun and Mercury. Comet had to plunge into the solar corona at a temperature of several million degrees. Scientists believed that C/2011 W3, core size of which is only about 100-200 meters, completely evaporate before perihelion passage. This did not happen; comet emerged from the back side of the Sun, having spent his crown for an hour, and sped away from the star, which was recorded satellite observations of the Sun. Some astronomers believe that the diameter of the nucleus of Comet Lovejoy is undervalued and is more than 500 meters. C/2011 W3 will return the next time the sun in 314 years.

In comet Hartley 2 found Earth Water

In comet Hartley 2 found Earth Water

In comet Hartley 2 found Earth Water

According to the dominant theory of the Earth, in the distant past, it was fairly dry, as the relative proximity to the sun did not allow a couple to freeze in ice, which could enter into the young planet. The main candidates for the carriers of water, scientists have always believed the comet. However, until recently the observations contradict this theory, as scientists studied comets index content contained was ice isotopes of hydrogen is at least two times higher than for the Earth’s oceans. Because of this, among others, began to appear on the hypothesis that 90 percent of the water on Earth may have to place meteorites, not a comet.

A study conducted by the Space Telescope “Herschel,” put everything in its place. The object of study was the comet Hartley 2 (103P/Hartley). Using a telescope mounted on a heterodyne detector (HIFI, Heterodyne Instrument for the Far Infrared) for the radiation in the far infrared range, which, according to experts, is currently one of the most sensitive instruments capable of detecting water in space, scientists were able to measure the ratio of isotopes in ice comet. It was found that the ratio is 1,61 x10-4, while the water on the Earth, it is 1,59 x10-4, that is almost the same performance.

The difference in the ratio of hydrogen isotopes in the six previous studies of comets and comet Hartley scientists explained once all previously studied comets came from the Oort cloud, and the Hartley 2 comes from the Kuiper belt. Accordingly, the history of these objects and the conditions for their formation are different. And if all the short-period comets in the isotopic composition of water identical to Hartley 2, which means that the main supplier of water in Earth’s oceans were just a comet from the Kuiper belt.

Omet Elenin collapsed

Omet Elenin collapsed

Omet Elenin collapsed

Recall that his comet received index C/2010 X1 (Elenin), Leonid Elenin discovered December 10, 2010 due to the automatic observatory ISON-NM, which is located in the U.S. state of New Mexico, but the remotely controlled by Russian scientists. The facility was the first comet discovered by Russian scientists in the past 20 years. Prior to that, our compatriots (in Soviet times) “lucky” to discover a comet in the 90’s of last century, when the astronomer from Krasnodar Boris Skorichenko with British colleagues discovered C/1989 Y1 (Skorichenko-George).

C/2010 X1 suddenly gained great fame among the proponents of conspiracy theories and doomsday preachers in 2012. They predicted that with its approach to the Earth comes a global catastrophe, as evidenced by its very name: that «Ele» means «extinction level event» (vseunichtozhayuschaya disaster), and «nin» – is «Nibiru in November» (meaning mythical planet Nibiru, the approach of which the earth was ostensibly a recipe for disaster.) In addition, the comet is also associated with the approach with her to the Earth of alien ships. But, alas, the comet was gone.

“The comet was supposed to appear in images of space solar observatory SOHO, but it is not. Apparently, it fell apart. Perhaps some fragments will continue to fly in the same orbit, and we can see them in October with ground-based telescopes, “- said Leonid Elenin.

Comet Elenin should have been closer to the Earth at a minimum distance – 0.23 astronomical units (34.9 million kilometers) – 16 October. However, in late August, amateur astronomers conducting observations of the comet, a significant decrease of brightness of its nucleus, indicating the beginning of the destruction of the celestial body. This is not unusual, since the death of comets – a fairly common event. Over the past 10 years, astronomers have recorded six decay of such heavenly bodies, except the so-called “solntsetsarapayuschih” Kreutz family of comets, which “killed” hundreds.

Dwarf comet 45P fly at a minimum distance from the Earth – just 8.9 million kilometers

August 15, 2011 45P/Honda-Mrkos-Pajdusakova dwarf comet flew closest to the Earth – all of 8.9 million kilometers. This will be the closest approach of a celestial body with the Earth since the beginning of the 20th century.

Dwarf comet 45P

Dwarf comet 45P

On Monday, 15 August 2011, at 08.16 GMT (12.16 MSK) Comet 45P will approach the Earth at a minimum distance equal to 8.9 million kilometers (0.06 AU), but despite this, the comet will not be watching in the northern hemisphere, because at this point it will be in the southern circumpolar constellation of Table Mountain. In addition, in the Southern Hemisphere to discover a comet without binoculars, too, will fail, because its brightness will reach only 7.8 magnitude, but the naked eye can only see objects not weaker 6th magnitude. In the northern hemisphere comet would return in mid-September: it can be observed by telescopes in the constellations of Leo and Virgo.

Dwarf comet 45P/Honda-Mrkos-Pajdusakova was opened on 3 December 1948, when it was at a distance of 64 million kilometers (0.43 AU) from our planet (as the object of 9 magnitude) Japanese astronomer Minoru Honda. Regardless of comet Honda also found Czech astronomer Antonin Mrkos and Slovak astronomer Lyudmila Paydushakova.

According to scientists, the size of the nucleus of Comet 45P is from 0.9 to 1.6 km, which is quite a bit compared to core subjects such as Comet Hale-Bopp (40-60 kilometers), or Comet McNaught (20-30 kilometers). 45P is classified as short-period comets with orbits that are in the ground between the Sun and Jupiter. In the case of 45P orbital period of about 5.3 years.

Hartley 2

Hartley 2

Hartley 2

Recall that the Deep Impact probe flew close to the nucleus of comet Hartley 2 at a distance of 700 kilometers in the autumn of last year. Comet has a form of “skittles” for bowling length of about 2 kilometers. Scientists have found that the comet “gush” mostly frozen carbon dioxide, not water ice, as previously thought. Emissions of water vapor and carbon dioxide are strong, but uneven. At the ends of the comet jets of carbon dioxide the most noticeable (especially in the lower part), and in the narrow middle part that’s true. But in the center of actively erupting steam, which is recycled to the ice under the sun. He is thrown together with carbon dioxide, which is also stored in a frozen state. In addition, the researchers found that less than half of the surface of the comet’s nucleus is studded with many giant boulders, highly reflective, a height of about 50 meters and a diameter of 80 meters.

It was also found that Hartley 2 rotates quite unusual: just around several axes with different rotation cycles, due to its unusual shape and uneven “heated” sunlight. With the passage of the probe in the vicinity of the nucleus of the comet he had to cross over cable, which, as it turned out, is not only out of the clouds of dust and carbon dioxide, but also fragments of ice, the largest of which reached the size of a basketball.

comet 81P Vilda

comet 81P Vilda

comet 81P Vilda

Recall that in 2006 the capsule returned to Earth in which there were samples of cometary material from the coma – the cloud of gas and dust that surrounds the comet nucleus 81P/Vilda (Wild 2).

81P/Vilda short-period comet was discovered in 1978 by a Swiss astronomer Poole Wilde. Scientists believe most of its history the comet had a more distant and less elongated orbit, but in 1974 a powerful gravitational field of Jupiter, which inadvertently comet approached, changed its trajectory. As a result of this period of the comet has decreased from 40 to 6 years, and now it is not removed more than 1.6 a. AU from the Sun.

Researchers led by graduate student Eve Berger of the University of Arizona made a detailed analysis of the mineral content of the cometary material, and concluded that the observed in the coma of comet minerals can occur at temperatures below 50-200 degrees Celsius. That is, at least in the distant past, the temperature inside the comet reaches a level where it starts to melt the ice and become liquid. In addition to the evidence of the existence of water in comets, scientists were able to determine the upper limit to which it can heat up. They found in the samples of the presence of the mineral iron sulfide and copper (Kuban). This mineral can exist at temperatures up to 99 degrees Celsius.

Comets spend most of its existence in the cold depths of the solar system, so the detection of signs of the presence of water ice in the stranger was an unexpected discovery for scientists.

SOHO comet discovered in 2000

With the help of the apparatus for observing the Sun SOHO, astronomers have discovered a lot of new comets, and on the eve of 2011 even noted a peculiar anniversary – 2000 comets.

SOHO comet discovered in 2000

SOHO comet discovered in 2000

SOHO

(Solar and Heliospheric Observatory) is a mission for the observation of the Sun and is a joint project of the European Space Agency (ESA) and the U.S. National Aeronautics and Space Administration (NASA). The device was launched on 2 December 1995 and began work in May 1996. It has on board 12 instruments to obtain images and measure the flow of solar radiation. The main objective is to study the SOHO our star, but for all time of the probe discovered more comets than any other machine.

Because the data is transmitted from the device to the Internet, more than 70 amateur astronomers from 18 countries over the past 15 years were able to observe not only the sun, but also discovering new comets. December 26, 2010 was a landmark event: it was discovered two thousandth account comet. This is done by a Polish amateur astronomer Michal Kusyak who studied the images transmitted from the probe. This is not his first discovery in the account Kusyaka already has over a hundred comets discovered by him in the study of SOHO images from 2007.

For the first ten years of the satellite astronomers found a thousand comets, but second thousand was opened just five years. A twofold increase in search speed is due to several factors: on the one hand, the increase in the number of those wishing to study made by the SOHO images, and the other – yet unexplained increase in the number of comets, in December 2010, it was discovered 37 new objects. This phenomenon has already received informal name “comet storm.”

Astronomers explain the mysterious outbreak comet 17P-Holmes

Astronomers from the United States and France presented a theory that relates the unexpected outbreak of the comet 17P-Holmes to the influence of solar radiation.

17P-Holmes

17P-Holmes

Glitter Comet Comet 17P-Holmes sharply increased 23 October 2007, when she was in the constellation Perseus. Only event of this kind can be explained by a collision with an asteroid, but a similar outbreak was recorded earlier in 1892.

The authors carried out observations of a comet in the infrared and optical regions, using telescopes and Palomar Observatories Holloway, as well as NASA space telescope “Spitzer.” The developed model of the explosive process, which caused an increase in brightness and release substances into the interplanetary medium, based on the results of these observations.

The nucleus of a comet is a certain amount of amorphous ice – water in the form of an amorphous solid. When this ice is heated to about 140 K, it becomes a normal crystal structure, a process accompanied by the release of heat and gases are stored with the inception of the comet. If the selection is in a closed cavity, in the case enters a positive feedback, which provides new volumes of crystallization of amorphous ice.

As the comet 17P-Holmes approaches the Sun at a distance of about two astronomical units, light emission may well heated substance on its surface to temperatures above 140 K. After repeated perihelion passage, as the authors, the pressure in one of the internal cavities exceeded the limit of her strength , resulting in an explosion, comparable in strength to the detonation of 31 kilotons of TNT. For providing of energy is needed to crystallize over a million tons of amorphous ice.

The conclusions of scientists agree is not all. So, David Jewitt (David Jewitt) University of California, Los Angeles, recalls the evidence of the existence of the low strength of comet nuclei, and considers that the gases should just come to the surface through cracks, not accumulating in cavities.

                                             

 Threaten a comet earth?

Scientists conducted disskusiyu on how much global catastrophes in the history of the Earth caused by the collisions of cosmic bodies to the surface of our planet. Most scientists agree that the Earth’s collision with an asteroid 65 million years ago marked the end of the dinosaurs, but are not sure how many were similar disasters in the history of Earth.

In fact, astronomers know that the inner solar system has been protected to some degree by Saturn and Jupiter, whose gravitational field caught comets and asteroids. Confidence in this hypothesis was confirmed July 20, 2009, when he appeared on the surface of Jupiter’s huge scar, the posterior probability of collision with a comet.

In the study of space, astronomers have modeled the process of penetration in the inner solar system from the Oort cloud comets. The Oort Cloud – the remainder of the nebula from which the solar system formed 4.5 billion years ago. It begins about 93 billion miles from the Sun and stretches for about three light-years.

Previously, scientists believed that most comets with long orbital period of 2000 to 1,000,000 years, which at the time there are about 3200, came from the outer part of the Oort cloud.

New research has shown that this is not the case. A new computer model is allowed to find a gap in the protection of the gravitational inner solar system, through which are able to penetrate the interior of the comet from the Oort cloud. Using this data, the researchers were able to estimate the number of comets in this part of the Oort cloud.

Using this estimate, the researchers calculated the number of comets with long periods of treatment, which could fall to Earth in the past 500 million years. As a result, it was found that during this time, our planet was faced with only two or three comets. Given that about 40 million years ago, three of the comet collided with the Earth at intervals of about one million years of each other, the scientists concluded that the meeting of the Earth with a comet from the Oort cloud is quite improbable.

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