Tailed guest over the Valparola pass

Heila Boppa is one of those comets that appear above the Earth once every 2,500 years, and was discovered at the moment when it was already very close to the Earth.

History of Hale Bopp's discovery

It happened on July 23, 1995, when American astronomers named Alan Hale and Thomas Bopp at the same time noticed a very close celestial object moving relative to the stars.

Astronomers decided to report this to the American Central Bureau of Astronomy. It is it that decides whether a new celestial body has been discovered. The message was immediately sent, and already on July 24 the whole planet learned about the discovery of a new comet. It bears its name in honor of the discoverers Alan Hale and Thomas Bopp.

The comet they discovered appeared above the Earth in the spring of 1996, or rather in May, and it was possible to see it without special instruments until the winter of 1997; only in December did it leave the horizon of planet Earth. Heila Boppa was and to this day remains the brightest of all that have been observed by scientists. Using complex calculations, they found out that it would be possible to see it next time only in 4390.

Alien device? Or incredible abilities?

Heila - Boppa C/1995 O1

Comet Hale Bopp has been studied by various scientists for a year and a half, as a result of which many discoveries were made, some of which caused a number of heated debates and versions. Among other things, this comet had a tail of the third type, unique in its composition. Usually the tail consists of a gas and dust tail, but this time there was also a sodium tail, which scientists discovered using special complex technical instruments. How neutral atoms were able to form a tail remains a mystery.

Also, this comet had unique properties of its nucleus; when rotating, it changed not only the axis of rotation and period, but even the direction of rotation. As a result, scientists made the assumption that it has two cores, but they could not prove this, nor could they refute it. There was another theory, some researchers suggested that there could be an alien device inside the comet, but no one could prove it.

Signal for self-improvement

Undoubtedly, the comet will go down in history as the most unique celestial body that people were able to observe in the 20th century, as well as the cause of mass crazes on the mystical and apocalyptic wave. All kinds of legends, myths and strange stories associated with the comet arose. But the story didn't end with stories alone.

A sect called “Heaven's Gate,” led by Marshall Applewhite, numbering 39 people, said goodbye to their lives, believing in his teachings. The mentor urged them to undergo a self-improvement program, after which the followers of his sect would leave their bodies and join the aliens. And the widely publicized legend that it was an alien ship hidden behind a comet became a signal for members of the sect. As a result, on March 22, 1997, the largest mass suicide in US history occurred.

American comet finder Alan Hale spent more than 400 hours of observation time searching for new “tailed stars.” And all to no avail. But then, on July 22, 1995, while waiting for the rise of Comet D'Arre, he decided to admire the numerous objects of the Sagittarius constellation. And the incredible happened - not far from M70, a diffuse object of 10.5 magnitude was discovered, which had not been there before. Alan Hale managed to discover a comet at a time when he was not looking for them!

Half an hour later, the comet was independently found by Thomas Bopp (USA). At the time of discovery, it had a small condensation in the center and a coma measuring about 2 arcminutes. She was also seen to have a small tail mark pointing north.

The first calculation of the comet's orbit was made four days after the discovery. It turned out that during these days she was located more than 6 AU. from the Sun, that is, behind Jupiter, and, nevertheless, already had such a fairly high brilliance. According to the calculated orbit, the comet was found on plates taken back in April 1993 at the Anglo-Australian Observatory. It had a magnitude of 18 m and a coma size of 0.4". Then the comet was separated from the Sun by 13.1 AU.

Soon other old photographs of the comet were discovered, which made it possible to quickly clarify its orbit. It turned out that it orbits in a highly elongated ellipse (eccentricity 0.997), and the orbital period is approximately 4000 years! In any case, a very rare and special “guest” is now flying towards Earth. Indeed, the fairly high brightness of the comet at a distant distance indicates its high absolute brightness. And if you believe the calculations, the comet will pass perihelion on April 1-2, 1997, and during the first four months of 1997 it will attract the attention of not only astronomers, but also all residents of the northern hemisphere of the Earth.

Throughout 1996, the comet will move north across the celestial sphere, while its brightness will increase. In November, the comet will pass through the northern part of the constellation Ophiuchus, near the globular star clusters M10 and M12, and will become visible to the naked eye in the evening hours.

From January 1997, the comet, already very bright (2 m), can be observed both in the evening and in the morning (the comet will rise much earlier than the Sun and set later). She will cross the constellations Eagle, Chanterelle, Cygnus, Lizard and in March will enter the constellation Andromeda. At this time, its visibility conditions will be the best, and the brightness is predicted to reach -1.7 m!

Thus, the comet will be almost equal in brilliance to Jupiter, and will be second only to the Sun and Moon! (Venus is not visible at this time). The comet will be a magnificent sight, but a truly unique sight will be seen by residents of Eastern Siberia on March 9, 1997, during the observation of a total solar eclipse. At the moment of totality, high above the eclipsed Sun and its brilliant corona, Comet Hale-Bopp will appear before observers in all its splendor. A spectacle that inspires horror and admiration! Screaming astrologers will probably predict at least the end of the world for this day.

We emphasize, however, that the brightness estimates presented here are based on preliminary data. There are indications that the comet experienced an outburst before its discovery. Therefore, it is now quite bright, and its brightness during its approach to the Sun is overestimated. However, it is obvious that this will be the “main” astronomical object of the beginning of 1997.

At the beginning of April 1997, the morning visibility and evening visibility of this beautiful comet will cease at the beginning of May. She will leave the Earth, and if she returns, it will not be very soon.

For those who want to independently calculate the coordinates of the comet, we present the elements of its orbit. Perihelion passage time, T per. =1997, March, 31.71081; eccentricity, e=0.9972029; perihelion argument, ω= 130.34251°; longitude sunrise, knot, Ω=282.47093°; orbit inclination, i=88.89915°; perihelion distance, q=0.9180262 a.u.

How it was

Alan Hale: - As a rule, I observe known comets about once a week, making estimates of their brightness. That night, the first after a week and a half of bad weather, I planned to observe two comets: Clark and D'Arre. After determining the brightness of Comet Clark, I had more than an hour to wait for Comet D'Arre to rise to a sufficient height above the horizon. There was nothing to do and I decided to admire the deep sky objects in the constellation Sagittarius. Looking through the telescope at M70, I immediately discovered an object in my field of view that had never been there...

Thomas Bopp: - On the evening of July 22, my friends and I went out of town in search of a darker place for observations. My friend Jim Stevens took a 45cm Dobson with him. After observing several objects in Cygnus, Jim suggested, "Let's look at the globular clusters in Sagittarius." After M22 and M28, we pointed the telescope at the M70 cluster. Jim went to get the map to select the next object, and I continued to admire M70, shaking the telescope a little back and forth. And then I noticed a diffuse object. Attempts to identify him using the atlas were unsuccessful. In addition, the object discovered its motion relative to the stars...

Opening. Several months passed, and during this time not a single cometary discovery was made - a very long period for that period of development of cometary astronomy. But this calm foreshadowed a storm, for after it a comet was discovered, which became very famous.

American Alan Hale spent hundreds of hours before he managed to discover the comet. And what a comet, too - a comet that later became famous. At the time of its discovery, on July 23, 1995, this comet was located near the globular star cluster M70 in the constellation Sagittarius. Hale was the first to establish that there was no mapped nebulous object in this part of the sky. As soon as he was convinced that the discovered object was moving against the background of the stars, he immediately hurried to send a message to the Bureau of Astronomical Telegrams.

Also, the American Thomas Bopp discovered the comet at about the same time, but not with his telescope. He and his friends observed nebulae and star clusters in the Stanfield (Arizona) area, and first saw the comet through the eyepiece of his friend's telescope. He saw an unknown nebulous speck near the well-known M70 cluster, and, after comparing this area of ​​the sky with star maps, he was unable to identify it. Hence Bopp suggested that this object was probably an unknown comet! Having reached this conclusion, he sent a telegram with a message about the discovery to the astronomical telegram office.

Confirmation of the comet discovery was made by the next morning and the comet was named Hale-Bopp - C/1995 O1 (Hale-Bopp). The discovery was officially announced in IAUC 6187. When discovered, the comet had a brightness of about 10.5m and was at a distance of hell 7.1 AU from the Sun!

A little later, the comet was discovered in images taken before its official discovery. T. Dickenson (Chiricahua Mountains, Arizona, USA) discovered the comet in an image taken on May 29. Robert McNaught (Anglo-Australian Observatory, Australia) found much earlier photographs of this comet in his archive. They date back to April 27, 1993. The brightness of the comet's nucleus at that time was about 18m, and the diameter of the coma was 0.4".

The comet becomes great. After the discovery, Hale-Bopp gradually increased its brightness and astronomers cautiously made optimistic predictions that the comet could become very bright.

Immediately after its discovery, many famous astronomers around the world observed it and estimated its brightness to be in the range of 10.5 - 12m.

At the beginning of August, the comet had a brightness of about 10.5m and a weakly compacted coma with a diameter of 2-3". There were signs of an embryonic tail - a slight extension of the coma in the northern direction. The comet very slowly increased its brightness and at the end of November disappeared in the twilight, reaching a brightness of about 10m.

After passing just two degrees from the Sun in early January, the comet was discovered again in early February at a magnitude of about 9m. Terry Lovejoy (Australia) described the comet as a well-concentrated object, noticeably brighter than last year. In March and April, Hale-Bopp was in the background and not many observations were made because C/1996 B2 (Hyakutake), the great comet of 1996, was shining in the sky. However, in mid-March the comet already had a magnitude of 8.5m, and by the end of April it reached 8m.

The first reported sighting of Hale-Bopp with the naked eye came on May 20, 1996, when Australian Terry Lovejoy was able to detect a hint of the comet under very good observing conditions. Using 10x50 binoculars, he estimated its brilliance at 6.7m and noted that the coma had a diameter of 15 minutes of arc, equal to half the visible disk of the full Moon. By the end of May, several more observers reported that they were able to detect the comet with the naked eye. By the beginning of summer, it had a brightness of 6.5m, and the angular diameter of the coma was 10-15".

During June, the comet continued to slowly increase its brightness, reaching 5.5m by the beginning of the average summer month. But after this, the tailed wanderer began to behave somewhat unexpectedly - until the end of July, Hale-Bopp did not increase its brilliance, remaining at the same level and causing astronomy lovers and professionals to worry. The situation did not change in August and early September; even, according to some estimates, during this period the comet weakened by 0.3m. However, in September its brightness began to gradually increase again, reaching a value of 5.3m by the beginning of October. Now the comet was at a distance of less than 3 AU. from the sun.

During this three-month period of very strange behavior of the comet, observatories around the world tirelessly collected various information about it. Later analyzes suggested that this unusual behavior may be caused by the fact that as it approaches the sun, the degree of heating of the cometary nucleus increases and various substances evaporate from its surface. As confirmation of this, the following data can be cited. The first detection of silicate emissions in the cometary spectrum occurred on July 8, methyl cyanide (CH 3 CN) - on August 14-17, cyanide ions were also detected in August.

During the fall and winter, the comet continued to gradually increase its brightness. By the end of October, estimates gave a value of 5m; the comet became brighter than 4m in mid-December, by which time it had approached the Sun by less than 2 AU. In our sky, at approximately the same time as last year, the comet was undergoing a period of minimal elongation, although it was several times higher than a year ago. The minimum elongation in this example - 21 degrees - the comet passed on December 21.

In January of the following year, the comet was already so bright that it could be detected with the naked eye even in heavily illuminated large cities.

Already by this time the comet had acquired a breathtaking appearance. The Internet at that time was not yet a widespread phenomenon, but those sites that talked about the appearance of a wonderful comet were very popular. The Internet has played a significant role in raising public interest in the great comet.

As the comet approached the Sun, it became brighter and brighter; in February it reached second magnitude and had a pair of clearly visible tails. The blue gas tail was narrower and pointed directly away from the Sun. A wide tail of dust, with a yellowish tint, curved, echoing the comet's orbit.

Thanks to a total solar eclipse that crossed Mongolia and Siberia on March 9, the comet was visible in the daytime sky.

Hale-Bopp passed its perihelion point on April 1, and the comet's closest approach to our planet occurred somewhat earlier - on March 22. It was on these days that it, having reached its maximum brightness, which stopped at a value of -0.8m, had the most stunning appearance. The brightness of the comet exceeded all the stars in the sky, with the exception of Sirius, and the double tail stretched 30-40 degrees. The comet was already visible in a fairly bright twilight sky, and at the same time, very atypical for bright comets, was observed throughout the entire night (the minimum distance of the comet from the Sun was as much as 0.9 AU, and comets that come close to ours usually become very bright central luminary).

This comet could be much more impressive if it came closer to Earth. For example, if Hale-Bopp approached us at the same distance as C/1996 B2 (Hyakutake) - the large comet of 1996 (0.1 AU) - then the comet's tail would stretch across the entire sky, and the brightness would exceed the brilliance of the full moon. However, even though the minimum distance of the comet from the Earth was 1.315 AU. (which is quite significant by cometary standards), Hale-Boppa was still very bright, its appearance and its tails were magnificent, although only partially visible to the naked eye.

How she left. After passing perihelion, the comet left the northern hemisphere of the sky and began to be observed by residents of the southern hemisphere. True, in the southern sky the comet was less bright and impressive than ours, and gradually weakened. The last naked-eye sighting of the comet was reported in December 1997, so C/1995 O1 was visible to the naked eye for 569 days, or approximately 18 and a half months. The previous record for this indicator belonged to the Great Comet of 1811, described in L.N. Tolstoy’s novel “War and Peace,” which was observed with the naked eye for 9 months.

In January 2005, Hale-Bopp crossed the orbit of Uranus, weakening to 16-17m. Moreover, even at this time, 8 years after passing perihelion, the comet had clear signs of a tail.

Astronomers believe that the comet will be visible with large telescopes until 2020, by which time its brightness will approach 30th magnitude, but it will be very difficult to distinguish the comet from distant galaxies of similar brightness.

Cometary orbit studies. The comet probably passed its previous perihelion approximately 4,200 years ago. Its orbit is almost perpendicular to the ecliptic, so it very rarely approaches planets. However, in March 1996, the comet passed at a distance of only 0.77 AU. from Jupiter (which is quite close, considering the mass of the giant planet). As a result of this approach, the comet's orbital period around the Sun was reduced to 2380 years, therefore Hale-Bopp should return to the inner regions of the Solar System again around 4377 years. The maximum distance of the comet from the Sun, which was 525 AU, has now decreased to 360 AU.

Results of scientific research. Comet C/1995 O1 (Hale-Bopp) was very actively observed by amateur astronomers and professionals near its perihelion and several very interesting conclusions were obtained for cometary science.

One of the most interesting discoveries was that this comet had a third type of tail, previously unknown to cometary science, in addition to the well-known gas and dust ones. In addition to them, Hale-Bopp was found to have a sodium tail, visible only with powerful instruments equipped with special filters.

Previously, sodium emission lines had also been observed in the spectra of some other comets, but sodium tails had never been observed. The Hale-Bopp sodium tail consisted of neutral atoms and extended approximately 50 million kilometers in length.

The source of the sodium seemed to be in the internal regions of the coma, although not necessarily in the core. Theoretically, there may be several possible pathways for the formation of sodium atoms. It has not been established exactly what mechanism was at work in the formation of the sodium tail of the great comet of 1997.

The Hale-Bopp sodium tail was located between the gas and dust tails. From this we can conclude that the sodium atoms were repelled from the head of the comet by radiation pressure.

Comet C/1995 O1 turned out to be rich in one of the atypical isotopes of hydrogen - deuterium, which was contained in cometary structures in the form of heavy water, known on earth. Moreover, the comet contained approximately twice as much deuterium as found in the Earth’s oceans. From this we can conclude that cometary impacts, which are believed to be a significant source of water on Earth, cannot be its only source if such amounts of deuterium are typical for other comets.

> Hale-Bopp

C/1995 O1 (Hale-Bopp)– long-period comet of the Solar System: description, characteristics with photos, the most popular comet, flyby of the Earth, detection, name.

Comet Hale-Bopp was a highlight when it approached Earth in the late 1990s. The closest approach was completed in 1997. It could be observed from the Northern Hemisphere for 18 months without the use of instruments.

It is believed to be one of the most popular comets in terms of mention in the media and the public. It was 1000 times brighter than Halley's Comet, and its double blue-white tail appeared even in bright skies.

Unfortunately, her arrival is overshadowed by sad events. Approximately 40 people from Heaven's Gate (San Diego) committed mass suicide.

The M70 Droplet and Comet Hale-Bopp

Comet Hale-Bopp was discovered independently by Alan Hale and Thomas Bopp. At that time, it was the most distant comet found by amateur astronomers. On July 23, 1995, both pointed their telescopes at the globular cluster M70. Hale said he was surprised to see a strange object that was not in the cluster a week ago.

The men sent the data to the Central Bureau of Astronomical Unions. It was surprising how bright Comet C/1995 O1 seemed at such a great distance. They realized that as she approached, she would put on a real light show. But predicting the behavior of a comet is difficult because they are balls of ice and rocks whose trajectory is influenced by other objects and events. Look at Comet Hale-Bopp in the photo.

The comet approached to a maximum of 193 million km. At that time, comet Hyakutake was also present in the sky, but it was inferior in brightness, although it was located closer

Comet Hale-Bopp sparks an Internet boom

The media constantly wrote about Comet Hale-Bopp, but the information also spread to the Internet, which was just gaining popularity. There were so many visitors that they literally created the first traffic jam. The comet home page received 1.2 million visitors per day, which set a record for resource traffic.

They began to monitor the comet through professional equipment, connecting the Hubble Space Telescope. He showed that the core covers 30-40 km. They also recorded dust flowing out of it, which was 8 times the average amount. The surface seemed incredibly dynamic.

Comet Hale-Bopp and Heaven's Gate

Heaven's Gate is a cult led by former music professor Marshall Applewhite. He promoted sexual abstinence and castration. Participants believed that their bodies were vessels that needed to be disposed of. They believed that an alien ship would arrive after the comet.

In late March 1997, Applewhite and 38 followers drank poison mixed with vodka and lay down to die. The bodies were found in a mansion in the suburbs of San Diego (California).

Next Arrival of Comet Hale-Bopp

The arrival of Comet Hale-Bopp created an amazing show. But the analysis showed that it had previously approached us 4,200 years ago, which means that next time it will return after millennia. Therefore, the researchers tried to extract as much information as possible from this arrival.

The first photos of comet Hale-Bopp appeared in 2002 from ESA, when the comet was flying at a distance of 2 billion km. Despite the low temperature, it is still surrounded by a large active dust and ice core (50 km in diameter).

Small Academy of Sciences for schoolchildren of Crimea “Seeker” and independent search work on the Internet.

Plan
1. Introduction.
2. Comet Hale-Bopp.
3. Comet Wirtanen.
4. Comet Williams.
5. Comet Kudo-Fujikawa.
6. Comet NEAT.
7. Comet Machholz.
8. Comet McNaught.
9. Comet Lulin.
10. Comet Holmes.
11. Comet Encke.
12. Comet Yi-SWAN.
13. Comet P/2010.
14. Main characteristics of comets over the past 13 years.
15. Conclusion.

Introduction
In addition to large planets and asteroids, comets move around the Sun. Comets are the longest objects in the solar system. The word “comet” translated from Greek means “hairy”, “long-haired”. As the comet approaches the Sun, it takes on a spectacular appearance, heating up under the influence of the sun's heat so that gas and dust fly away from the surface, forming a bright tail.

The appearance of most comets is unpredictable. People have been paying attention to them since time immemorial. It is impossible not to notice in the sky a spectacle so rare, and therefore terrifying, more terrible than any eclipse, when a foggy body is visible in the sky, sometimes so bright that it can sparkle through the clouds (1577), eclipsing even the Moon. And from the depths of the uninvited heavenly guest, huge tails burst out...

I decided to do this work because I am interested in learning more about the comets of my life. Find out their maximum visibility, perihelion, minimum distance from the Earth and their features.

Comet Hale-Bopp — 1997

Comet Hale-Bopp (C/1995 O1) is a long-period comet that was perhaps the most “observed” comet of the 20th century, and one of the brightest over the past few decades. It was visible to the naked eye for a record 18 months, double the previous record set by the Great Comet of 1811.

The comet was discovered on July 23, 1995, at a very great distance from the Sun (about 7.2 AU), suggesting that it will be quite bright when approaching Earth. Although the brightness of comets is very difficult to predict with any degree of accuracy, this comet met and exceeded expectations when it passed perihelion on April 1, 1997. It is sometimes called the "Great Comet of 1997."

The comet was discovered independently by two American observers, Alan Hale and Thomas Bopp. Hale had spent many hundreds of fruitless hours searching for comets, and near his home in New Mexico he was observing known comets when, around midnight, he suddenly encountered a nebulous object of magnitude 10.5 near the globular star cluster M70 in the constellation Sagittarius. Hale first determined that there were no other deep space objects near this cluster. He further discovered that the object was moving noticeably against the background of stars (and therefore was in the solar system), and wrote an email to the Central Bureau of Astronomical Telegrams, which tracks astronomical discoveries.

Bopp did not have his own telescope. He was outdoors with his friends near Stanfield, Arizona, observing star clusters and galaxies when a speck of light flashed before his eyes through the eyepiece of his friend's telescope. After consulting star charts, Bopp realized that this speck was a new object, and sent a telegram to the same place as Hale.

The next morning, the discovery of a new comet was confirmed, which was given the name Comet Hale-Bopp and the designation C/1995 O1. The discovery was announced in Circular No. 6187 of the International Astronomical Union. At the time of discovery, the comet was at a distance of 7.1 AU. e. from the Sun.

Soon, earlier photographs of the comet were discovered. Thus, Terence Dickinson found the comet in his photograph taken on May 29, 1995, and Robert McNaught found it in his photograph taken on April 27, 1993, that is, two years before the discovery of the comet. At that time, its magnitude was 18m, and its distance from the Sun was 13.0 a. e.

The comet became visible to the naked eye in May 1996. Although the increase in brightness slowed somewhat in the second half of the year, scientists optimistically predicted that the comet would be very bright. Due to its proximity to the Sun, observations were difficult in December 1996, but in January it became clearly visible again and was so bright that it could be seen even by the streetlights of large cities.

View of the comet in early 1997.

Approaching the Sun, Comet Hale-Bopp became increasingly brighter: in February it reached the 2nd magnitude, and one could already distinguish its tails - a bluish ion tail, directed in the direction opposite to the Sun, and a yellowish dust one, curved along the comet's orbit. A solar eclipse in Eastern Siberia and Mongolia on March 9 made it possible to see the comet during the day. On March 23, 1997, Comet Hale-Bopp approached the Earth at a minimum distance of 1.315 AU. e. (196.7 million km).

At perihelion on April 1, 1997, the comet presented a stunning spectacle. With an average magnitude of −0.7, it shone brighter than any star (excluding Sirius), and its two tails stretched across the sky by 15-20 degrees (and parts of them invisible to a simple observer - by 30-40 degrees). The comet could be observed just after dusk; and although many “large” comets passed perihelion were close to the Sun, Comet Hale-Bopp could be observed in the northern hemisphere all night.

The development of the Internet at that time led to the emergence of many sites that tracked the details of the comet's flight and even published daily photographs. Thus, the Internet played a large role in generating unprecedented public interest in Comet Hale-Bopp.

Comet Hale-Bopp could be even more impressive. If it had approached the Earth at the same distance as Comet Hyakutake did in 1996 (0.1 AU), it would have exceeded Venus in brightness, reaching −5th magnitude.

After passing perihelion, the comet moved to the southern celestial hemisphere and its brightness began to weaken. The comet looked much less impressive to southern observers, but they were able to see its brightness gradually decrease throughout the second half of 1997. The last known observation of the comet with the naked eye was in December 1997, meaning it was visible for about 18 and a half months. This period broke the previous record of 9 months, set by the Great Comet of 1811.

Now Comet Hale-Bopp is moving away, and its brightness continues to decrease. In August 2004, it flew beyond the orbit of Uranus, and as of mid-2008, it was located at a distance of about 26.8 AU. e. from the Sun. However, it is still being tracked by astronomers. The reason for this is the unusually long activity of the comet. Recent observations (October 2007) indicate that the comet still has a coma with a brightness of about 20m. It is assumed that the reason for the unusually long activity lies in the slow cooling of the giant comet nucleus.

The comet is expected to remain observable with large telescopes until about 2020, when its brightness drops to 30m. It is estimated that in one of its next returns, Comet Hale-Bopp has a 15% chance of becoming circumsolar, and serving as the progenitor of a new family, such as the Kreutz family of comets.

It is most likely that the penultimate time the comet passed perihelion was about 4,200 years ago. Its orbit is almost perpendicular to the ecliptic plane, so close approaches to planets are very rare for it. But in March 1996, the comet flew by at a distance of 0.77 AU. That is, from Jupiter - close enough for the gravity of this planet to affect its orbit. At the same time, the point of the orbit farthest from the Sun (aphelion) approached from 600 to 350 AU. e. The comet's orbital period has been reduced to 2400 years, and now its next appearance in the Solar System is expected around 4390.

Comparison of orbital lengths: Sedna (left), comets Hale-Bopp (bottom, orange line); daylight (yellow sphere), shock wave boundary (blue sphere); the position of Voyager 1 (red arrow) and Pioneer 10 (green arrow); Kuiper belt (gray ring); the orbit of Pluto (a small inclined ellipse inside the Kuiper belt and Neptune (the smallest ellipse).

As the comet approached the Sun, it was intensively studied by astronomers. In doing so, some important and interesting discoveries were made. One of the most significant results was the discovery of a third type of tail on the comet. In addition to the usual gas (ion) and dust tails, there was also a weak sodium tail, visible only with the help of powerful instruments and a complex system of filters. Sodium streams had previously been noticed in other comets, but in none of them did they form a tail. At Comet Hale-Bopp, it consisted of neutral atoms and stretched almost 50 million kilometers in length.

The source of sodium was located inside the comet's head, although not in the nucleus itself. There are several possible mechanisms for the formation of such a source, for example, collisions between dust particles surrounding the core, or the “squeezing out” of sodium from these particles under the influence of ultraviolet light. It is not yet entirely clear which of the mechanisms was more evident in this case.

While the dust tail simply stayed behind the comet, tracing its trajectory, and the ion tail was pointed straight away from the Sun, the sodium tail lay between the two. This suggests that sodium atoms were pushed out of the comet's head under light pressure.