Chilean astronomers discovered an asteroid with the shortest orbital period of any known asteroid in the Solar System using the potent 570-megapixel Dark Energy Camera (DECam). They just completed this ten days ago. The roughly one-kilometer-wide asteroid approaches the Sun by 20 million kilometers every 113 days (12 million miles or 0.13 au).
The asteroid 2021 PH27 has the lowest period and semi-major axis of any asteroid that is currently known to exist in our Solar System. The only planet with a shorter period and semi-major axis is Mercury. The asteroid experiences the highest general relativity effects of any known object in the Solar System due to its close proximity to the Sun.
By examining data from the Dark Energy Camera (DECam) on the Vctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile, Scott S. Sheppard of the Carnegie Institution of Science discovered the asteroid 2021 PH27. On August 13, 2021, when night fell, Brown University students Ian Dell’Antonio and Shenming Fu captured images of the asteroid in the sky.
Sheppard used DECam to collect data for the Local Volume Complete Cluster Survey while working with Dell’Antonio and Fu. Most of the major galaxy clusters in the nearby universe are being examined by this survey. They stopped observing some of the largest objects that were millions of light-years away in order to search for asteroids that were considerably closer to Earth.
One of the top wide-field CCD imagers in the world is DECam. It was created for the Dark Energy Survey (DES), which was financed by the DOE. It was constructed and tested at Fermilab and operated by the DOE and NSF from 2013 to 2019. Currently, DECam is employed for a variety of science programs. The DECam science archive is maintained by the Community Science and Data Center (CSDC). The CTIO and CSDC initiatives are run by the NOIRLab at NSF.
Twilight, just after sunset or just before sunrise, is the greatest time to search for asteroids that are inside Earth’s orbit and pointed in the general direction of Mercury and Venus. Any stargazer will tell you that Mercury and Venus usually appear to be close to the Sun in the sky and are always the easiest to spot just before or after sunrise or sunset. The same applies to asteroids that orbit near to the Sun.
After 2021 PH27 was found, David Tholen of the University of Hawai’i measured its position and figured out where it could be seen the next night. After that, on August 14, 2021, DECam and the Magellan Telescopes at the Las Campanas Observatory in Chile both looked at it again. Then, on the evening of the 15th, Marco Micheli of the European Space Agency used the Las Cumbres Observatory network of 1- to 2-meter telescopes to look at it from CTIO in Chile and from South Africa. Other astronomers used DECam and Magellan to look at the newly found asteroid as well.
According to Sheppard, astronomers are very willing to put their own science and observations on hold in order to pursue new, intriguing discoveries like this one, despite the fact that their telescope time is very valuable due to the international nature of their work and their love of the uncharted.
Oval-shaped orbits around the Sun are followed by planets and asteroids. The semi-major axis, which is the broadest portion of the oval, has a radius. 2021 PH27 has an elliptical orbit with a semi-major axis of 70 million kilometers (43 million miles or 0.46 au), giving it a 113-day orbital period and crossing the orbits of both Mercury and Venus.
It might have originally been located in the main asteroid belt between Mars and Jupiter, but gravitational disturbances from the inner planets caused it to drift closer to the Sun. On the other hand, it may be an extinct comet from the outer Solar System that was drawn into a tighter, shorter-period orbit as one of the terrestrial planets passed by due to its high orbital inclination of 32 degrees. We shall discover more about the asteroid’s origin as further observations are made of it.
Its orbit is likely unstable for extended periods of time as well. It is likely to either be pushed out of the inner Solar System or crash with Mercury, Venus, or the Sun in a few million years by the gravity of the inner planets.
Because the Sun’s radiation frequently obscures asteroids in the inner solar system, astronomers have difficulty locating them. Due to the Sun’s heat and gravitational tides, asteroids are subjected to a great deal of physical and thermal stress as they approach the Sun so closely. These forces could lead a few of the weaker asteroids to fragment.
According to Sheppard, the ratio of asteroids that are near Earth and Venus to those that are far away will reveal information about the asteroids’ composition and strength. Astronomers may learn how many near-Earth asteroids are loosely held piles of rubble rather than solid chunks of rock if the number of asteroids in the same orbit as 2021 PH27 appears to be declining. This could have an impact on how we handle and attempt to stop asteroids that may be heading for Earth.
To complete the census of asteroids near Earth, it is crucial to comprehend the number of asteroids inside Earth’s orbit, according to Sheppard. Most surveys are conducted at night, when the Sun is not visible, making it difficult to locate some of the asteroids that are most likely to impact Earth during the day. According to him, 2021 PH27’s surface temperature reaches about 500 degrees C (around 900 degrees F) at closest approach, which is hot enough to melt lead because of how close it is to the Sun.
The closest object in the Solar System to the Sun, 2021 PH27, has the strongest effects of general relativity. This manifests as a very tiny precession of the asteroid’s elliptical orbit over time, which occurs at a rate of around one arcminute per century.
We can see the asteroid sliding behind the Sun from where we are right now. It’s known as a solar conjunction. Early in 2022, it is anticipated to return to Earth’s line of sight, allowing for further observations to more precisely pinpoint its orbit and give the asteroid a formal name.
Soucre: theancientzen.com
