“Amazing”, said Russian-origin astronomer Margarita Safonova, of the Indian Institute of Astrophysics after looking at comet C/2022 E3 (ZTF) which has come near earth after 50,000 years on the early morning of Jan 3, 2023.
She said she had been able to get several photos of the present comet with the Institute’s Himalayan Chandra Telescope located at Hanle, Ladakh, and will be releasing it soon on the Outreach page of the official website of the institute.
“There are two tails, a straight ion tail moving away from the Sun and a dust tail which is curved because it follows the comet’s orbit”.
People on earth are going to have a chance to view this celestial traveler after 50,000 years in Jan-Feb 2023.
Comet C/2022 E3 (ZTF) last came near earth about 50,000 years ago when humans were still evolving, and Neanderthals were roaming on the earth.
Comet E3 was first spotted by the Zwicky Transient Facility at Palomar Observatory in Californium, on March 2, 2022. The Zwicky Transient Facility (ZTF) is a public-private partnership aimed at a systematic study of the optical night sky. Using an extremely wide-field of view camera, ZTF scans the entire Northern sky every two days.
Currently, the comet is around 188 million kilometers away. It will be the closest point to the sun on January 12 and be near Earth on February 1, even then it will be about 41 million kilometers away from earth.
One must keep in mind that the comet is in its regular orbit of the sun. Its orbital path must be huge as it is touching earth after 50,000 years.
If we are in northern hemisphere and skywatch before dawn and if light pollution does not act as a spoiler one may be able to watch in January the comet in naked eye or at best with a binocular, for those in the southern hemisphere the comet will be seen around Feb. 2, 2023, when it comes closest to earth in its orbit. It will be best seen from dark locations. Astronomers are hoping it to brighten up getting closer to earth but if it does not it may just look like a white smudge in the sky.
According to the National Aeronautics and Space Administration, USA comets are leftover matter from the dawn of our solar system 4.5 billion years ago, cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When a comet’s orbit brings it close to the Sun, it heats up and spews dust and gases turning into a giant glowing head larger than most planets.
The dust and gases form a tail that stretches away from the Sun for millions of miles. There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.
The current number of known comets NASA says is 3,743.
Sighting a comet in earlier days used to alarm people as a long haired planet appearing suddenly in the sky. Chinese astronomers kept extensive records for centuries, including illustrations of characteristic types of comet tails, times of cometary appearances and disappearances, and celestial positions. These historic comet annals have proven to be a valuable resource for later astronomers, according to NASA.
While predictable comets may orbit between a few years or a few hundred years long-period comets like this one may come once in thousands of years and many of these are supposed to arrive from the Oort Cloud, a collection of huge rocks long way away from the Sun. These comets can take as long as 30 million years to complete one trip around the Sun.
NASA says that each comet has a tiny frozen part, called a nucleus, often no larger than a few kilometers across. The nucleus contains icy chunks, frozen gases with bits of embedded dust. A comet warms up as it nears the Sun and develops an atmosphere or coma.
The Sun’s heat causes the comet’s ice to change to gases so the coma gets larger. The coma may extend hundreds of thousands of kilometers. The pressure of sunlight and high-speed solar particles (solar wind) can blow the coma dust and gas away from the Sun, sometimes forming a long, bright tail. Comets actually have two tails―a dust tail and an ion (gas) tail.
NASA’s Deep Space 1 spacecraft flew by comet Borrelly in 2001 and photographed its nucleus, which is about 8 kilometers (5 miles) long.
How do you get to know what is the orbit and periodicity of the comet?
Mr Ramanujam said, You observe the comet and its path for a period of time to find out its orbit. You can extrapolate backwards in time to find when the comet last came near earth.
He said the furthest this comet will go from sun will be in 25,000 years and the nearest to sun it will be around 165 million kilometers from sun (Jan 12 ).
Interestingly, he said, it has a perpendicular orbit to the plane of the planets (instead of 90 degrees its inclination is about 110 degrees).
According to NASA, NASA’s Stardust mission has successfully flown within 236 kilometers of the nucleus of Comet Wild 2 in January 2004, collecting cometary particles and interstellar dust for a sample return to Earth in 2006. The photographs taken during this close flyby of a comet nucleus show jets of dust and a rugged, textured surface. Analysis of the Stardust samples suggests that comets may be more complex than originally thought. Minerals formed near the Sun or other stars were found in the samples, suggesting that materials from the inner regions of the solar system travelled to the outer regions where comets formed.
Another NASA mission, Deep Impact, consisted of a flyby spacecraft and an impactor. In July 2005, the impactor was released into the path of the nucleus of comet Tempel 1 in a planned collision, which vaporized the impactor and ejected massive amounts of fine, powdery material from beneath the comet’s surface. En route to impact, the impactor camera imaged the comet in increasing detail. Two cameras and a spectrometer on the flyby spacecraft recorded the dramatic excavation that helped determine the interior composition and structure of the nucleus, NASA says.
| Posted by Sameer Khan | 
