Here it comes! (2023 DZ2)

 Asteroid, Minor Planet, Solar System  No Responses »
Mar 232023
 

Asteroid 2023 DZ2 is headed towards a close approach to Earth on the afternoon of the 25th of March 2023 at 1451 CDT (1951 UTC). It will pass by at an estimated distance of 108,000 miles or just under half a lunar distance. It is estimated to be about 70 meters in diameter. A light curve shows a 6-minute rotation and about a half a magnitude range in brightness leading to the conclusion that the asteroid is not spherical.

 

This is an animation of 2023 DZ2 as it approaches the Earth. Taken on the morning of the 23rd of March, it is a set of twenty 300 second exposures.

2023 DZ2’s orbit.
(Graphic courtesy of the JPL Small-Body Database Browser)

2023 DZ2 is classified as an Apollo class asteroid. These asteroids orbits have an semi-major axis greater than that of the Earth but their perihelion is less than the Earth’s aphelion. Simply stated, these asteroid’s orbits take them closer to the Sun than the Earth and further from the Sun than the Earth. This means the asteroid’s orbit crosses the Earth’s orbit.

 Posted by at 12:36

2015 RN35 (Near-Earth asteroid) (16 Dec 2022)

 Asteroid, Minor Planet, Solar System  No Responses »
Dec 172022
 

Near-Earth asteroid 2015 RN35 flew past the Earth on the 15th of December 2022 at a distance of roughly 426,000 mi (686,000 km). The size of the asteroid is estimated to be in the of 200 to 460 feet in diameter. This is close enough and large enough to get the usual internet suspects to issue dire warnings. But as usual, those predictions were way overblown.

Due to the proximity of the event to year-end holidays some were even calling it a “Christmas Asteroid”. However, with the closest approach on the 15th and the predicted visibility ending by the 19th I would argue that “Hanukkah Asteroid” would be a better moniker.

Unfortunately, on the 15th, the PTO was configured to image main belt asteroids, not near-Earth asteroids. So, it was quite a challenge to find and image something moving as quick as the asteroid was. I fully expected to get a streak as the asteroid flew through the telescope field-of-view. However, I was not expecting this.

The image shows a sparce star field with three streaks running from top to bottom, each a different brightness due to their color. There are an additional two short streaks paralleling the others where the aircraft lights were flashing.

Aircraft formation lights [CV:1x60s]

Even though I live less than a mile from the end of a major airport’s runway, I rarely get photo-bombed by one of the aircraft. There is a lot of traffic, but I am looking at too small of a chunk of sky to have one pass through that little spot. By pointing the scope in front of the anticipated path of RN35 and taking a series of blind exposures, I was able to get a quick look at it as it passed by.

The image shows a star field with a long streak as asteroid 2015 RN35 passes from middle center to upper right.

2015 RN35 [CV:1x300s]

This image was enough to encourage me to set up a different software configuration on the next night (the 16th) and take the series of images used to make the following animation. This is a series of sixty 60 second shots. Yes, you do see a satellite pass through the FOV right at the end of the video.

The asteroid is in a 654 day orbit with its aphelion just outside of Mars’ orbit.

2015 RN35’s orbit.
(Graphic courtesy of the JPL Small-Body Database Browser)

 Posted by at 10:27

Here comes Didymos (17 Sep 2022)

 Asteroid, Minor Planet, Solar System  No Responses »
Sep 222022
 

On the 26th of September NASA’s DART mission will intentionally crash a spacecraft into a moon of the asteroid (65803) Didymos. This will be the first test of a kinetic impactor to see if energy can be used to change the orbit of an asteroid. The moon’s name is Dimorphos and it orbits its parent asteroid in 11.9 hours. If successful, the impact is expected to reduce the orbital period to 11.8 hours. This will make the moon orbit slightly closer to Didymos. The ability to add or subtract energy from a potentially hazardous asteroid or comet may be critical at some future date.

This clip is ten 300 second images. The moon Dimorphos is too small for me to see.

 Posted by at 21:16

2020 SO – Say goodbye to our little friend.

 Asteroid, Spacecraft  No Responses »
Feb 032021
 

As a quick review, 2020 SO is the Centaur upper stage that launched NASA’s Surveyor 2 towards the Moon. It then entered a heliocentric orbit that closely matched the Earth’s. It had flown past the Earth unobserved several times but the September 2020 pass was observed by the PAN-STARRS 1 system in Hawaii and it was quickly realized that it would be captured by the Earth. In December, NASA verified that the object was not an asteroid but the long lost spacecraft.

It has been in Earth orbit since November 2020 when the Moon’s gravity slowed 2020 SO’s speed and Earth loosely captured it. Last night (2 Feb) the spacecraft made a final close pass by the Earth at about half the distance to the Moon. This time the Moon’s gravity added energy to the object and it will break free of Earth’s gravity on the 8th of March.

SO 2020’s Earth orbit.
Image via Phoenix7777/ Wikimedia Commons.

This animation is 120 30-second exposures. I attempted to calibrate the individual exposures but, as mentioned above, the object was very close to the Moon and there was a huge gradient in the images due to scattered light. So the raw images made a better video.

 Posted by at 13:20

“Asteroid” 2020 SO

 Asteroid, Spacecraft  2 Responses »
Nov 232020
 

UPDATE: During yesterday’s (01 December) close pass scientists used NASA’s Infrared Telescope Facility (NIRTF) on top of Mauna Kea to compare 2020 SO’s IR signature with that of a Centaur upper stage currently in Earth orbit. They matched, leading the scientists to state that 2020 SO is indeed the Centaur upper stage that sent Surveyor 2 towards the Moon in 1966.

I was finally able to image MPC object 2020 SO last night. The object was discovered on the 17th of September by the Pan-STARRS 1 telescope and given the designation 2020 SO. This animation is a series of 300 second images and you can see by the amount the object streaked, how fast it is moving. That apparent movement is due to its proximity. The object is currently trapped by Earth’s gravity and will remain in orbit for several months until the Earth and Moon’s gravity combine to send it back into its own heliocentric orbit.

What is unique about 2020 SO is its orbit and speed prior to its encounter with Earth is very unusual for an asteroid. It is not unusual for a manmade object launched from Earth. 2020 SO is suspected to be the Centaur upper stage that sent the 1966 Surveyor 2 probe towards its rendezvous with the Moon. The probe impacted the Moon but the Centaur continued, as expected, into an solar orbit. The Centaur was first successfully flown in 1963 and has been upgraded several times.

Atlas V version of the Centaur upper stage. Credit: NASA (2005)

I am guessing here but I think the late, great Arecibo radio telescope would have been tasked with observing the object during its close December pass. Spectroscopic studies will be carried out with the intent on identifying the object as the Centaur based on its titanium-oxide white paint.

 Posted by at 15:58
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