Decoding the orbit of 1994 PC- 1: NEO that passed in January 2022.

Near-Earth Objects known as NEOs always have a certain factor of risk embedded in them for our planet. Also, one of the popular theories for the extinction of dinosaurs is the impact of a huge asteroid, we know what impact a NEO can have if it goes undetected.

This led to Astronomers all over the world keeping an eye and studying closely such potential NEOs. The technology to detect NEOs begin to start improving after the 1990s. Perhaps, the best known NEO currently would be Apophis, which will pass Earth in 2029 but was detected as early as 2004.

There is a need to identify NEOs and study in detail the ones which are most dangerous for Earth. The asteroid which passed Earth recently was studied in detail in 2011 with its orbit being plotted by computer simulations. Using Meade LX200-ACF Telescope, the asteroid was observed with the intention to study its orbit in detail. Using the Right Ascension (RA) and Declination(Dec) information, they tracked the asteroid in the night sky.

RA and Dec are basically pointers of an object in the night sky. If one has the information of RA and Dec of a certain object, then one can spot the object in the sky using a telescope.

For analyzing the data, they calculated the orbital elements of the asteroid using the Method of Gauss. Then the data was further sent to processing. Now, to obtain the orbit of the asteroid, the RA and Dec of the asteroid were observed at each different observation. Using three of the observations they calculated the orbital elements of the asteroid.

Asteroid (7482) 1994 PC1 was in the constellation Pisces on January 18, 2022, the night of the closest approach to Earth. Illustration by Eddie Irizarry/ Stellarium.

The orbital elements included eccentricity, semi-major axis, and the inclination of the orbit. The eccentricity of the orbit was found to be 0.3272 which meant the orbit was elliptical in nature. The semi-major axis of the ellipse was found to be 1.3401 A.U. long. There was a large inclination of the orbit of the asteroid from the plane of this solar system, nearly 33 degrees.

Based on computer simulations, it was determined that the distance of the closest approach would be around 0.04 A.U. The time of closest approach was determined around the year 2056, which was incorrect as we now know it passed in 2022 but the date was dependent upon the accuracy of the result of the study then performed.

At the time when the study was performed, it was shown that the asteroid was in opposition in its orbit, i.e. at a position opposite to the sun when viewed from Earth.

Furthermore, their results corroborate the fact that the asteroid is a potentially hazardous object since it reaches very close to the Earth during its orbit.

A visualization of the Earth’s and 1994 PC1’s orbits showed that the asteroid will most likely not collide with our planet in the near future, though the point of closest approach will be January 21, 2056. This was determined through a 100-year-long simulation of the inner Solar System and the asteroid. In order to reach a more definite conclusion on possible asteroid impact, however, more data would have been required.

The closest approach to Earth occurred on January 18, 2022, at 4:51 p.m. EST (21:51 UTC). This approach was the closest for this asteroid for at least the next 200 years for which astronomers have calculated its orbit.

But the study got the orbit of the asteroid 1994 PC 1 right to an extent and it indeed passed close to Earth. Although it won’t be the largest asteroid ever to sweep past Earth. That honor belongs to the asteroid 1981 ET3, which flew by and missed colliding with Earth on September 1, 2017. That asteroid is estimated to be between 2.5 miles and 5.5 miles wide, and it will make another pass on September 2, 2057.

Such studies are important as they help scientists understand the potential risks that the NEOs would have on Earth, and the earlier they have detected the better it is for them to plan in advance how they can be averted (e.g. DART mission).




Just trying to use Science to explain concepts of Astrophysics to the common folk.

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Manas Karnik

Manas Karnik

Just trying to use Science to explain concepts of Astrophysics to the common folk.

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