The large potentially hazardous asteroid 2011 UL21 is safely approaching, no risk for our Earth – 27 May 2024
Next 27 June, the large potentially hazardous asteroid (415029) 2011 UL21 will have a relatively close encounter with our planet, coming as close as 6.6 million km from the Earth, about 17 times the distance, a noteworthy fly-by, though. We will show it live, online, for Asteroid Day.
Potentially Hazardous Asteroid (415029) 2011 UL21, an image: 24 May 2024.
On June 27th, at 20:16 UTC, the potentially hazardous asteroid (415029) 2011 UL21 will have a relatively close encounter with our planet, coming as close as 6.6 million km from the Earth, about 17 times the distance to the Moon. There is absolutely no risk for our planet.
However, this passage is quite noteworthy.
Potentially Hazardous Asteroid (415029) 2011 UL21 has a significant diameter, estimated between 1.7 and 3.9 km (source: JPL/NASA), with some studies suggesting a value of 2.3 km. These estimates make it one of the largest asteroids to have recently passed near Earth.
Moreover, by analyzing the list of close approaches by such bodies, made available by the Center for Near Earth Object Studies (CNEOS) of the Jet Propulsion Laboratory, it can be concluded that after this rendez-vous, 2011 UL21 will be among the top 10 largest asteroids to have passed within 7.5 million km from the Earth since January 1, 1900.
“The term ‘Potentially Hazardous Asteroid’ (PHA) is a precise formal definition, referring to minor planets larger than approximately 140 meters that can come within 7.5 million km from the Earth,” says Gianluca Masi, astrophysicist and scientific director of the Virtual Telescope Project. “In other words, only the largest asteroids capable of approaching close enough to our planet are flagged as PHAs, which does not mean they are going to hit the Earth, but they nonetheless warrant a better monitoring,” concludes the astrophysicist.
The attached image shows the potentially hazardous asteroid (415029) 2011 UL21, captured on May 24, 2024, by Gianluca Masi, Ernesto Guido, and Marco Rocchetto, using a 350mm f/3 robotic telescope installed in Australia, part of the Spaceflux global network, a leading company in Space Situational Awareness. At the time of the observation, the object was very low on the horizon, with the full Moon heavily interfering with the observations.
Potentially Hazardous Asteroid (415029) 2011 UL21, animation: 24 May 2024.
Back to 2011 UL21, its upcoming passage will first be observable from the Southern hemisphere, essentially until the date of the fly-by. From the evening of June 27th, it will quickly move in the sky, becoming easier to observe from the Northern part of the world. 2011 UL21 will reach its maximum apparent brightness on the night of June 28-29 (magnitude 11.7), when it will be observable through telescopes of about 100mm (4-inches) in diameter. Throughout the first week of July, it will stay within reach of amateur instruments.
During the best days for viewing, 2011 UL21 will move through the constellations of Hydra, Virgo, Libra, and then will cross Serpens, heading towards Hercules.
The passage will occur in conjunction with the 2024 edition of the famous Asteroid Day, an international event launched in 2015 and officially recognized by the United Nations in 2016, aiming to educate the public about the risks and opportunities of asteroids. This event is held annually on June 30th.
To honour the celebration, the Virtual Telescope Project will host a live feed covering the potentially hazardous asteroid (415029) 2011 UL21 on June 27th, starting at 20:00 UTC., covering the time of the fly-by. The live stream will be conducted by astrophysicist Gianluca Masi, scientific director of the Virtual Telescope Project and National Coordinator for Italy of Asteroid Day, who will remotely use the robotic telescopes of the Virtual Telescope Project installed in Manciano, in Tuscany Maremma, under the purest skies free from light pollution in peninsular Italy.
Back to “upcoming events” page
Support The Virtual Telescope Project!
Support us! Please, donate and receive unique, LIMITED EDITION set of images of the stunning comet 12P/Pons-Brooks with Andromeda Galaxy, of potentially hazardous asteroids, space stations and much more, specifically made for supporters like you!
(you can adjust the amount later)
