2023 DZ2

 is an asteroid roughly 70 meters in diameter, classified as a near-Earth object of the Apollo group, and originally a Virtual Impactor (VI). It was first observed on 27 February 2023, when it was 0.11 AU from Earth, with the Isaac Newton Telescope by Ovidiu Vaduvescu, Freya Barwell, and Kiran Jhass (ING and University of Sheffield student support astronomers) within the EURONEAR project. It passed 174644 ± 0.9 km of Earth on March 25, 2023. This is a little less than half the distance to the Moon. This was the largest asteroid to approach this close since 2019 OK. On March 21, 2023 with a 66-day observation arc, it was removed from the Sentry Risk Table. Due to the highly precise radar observations on 25 March 2023 we know that the 2004 Earth approach was closer than the 2023 approach.

The 2023 approach was visible to amateur astronomers with modest telescopes and telescopes equipped with an image sensor. From 20–24 March 2023 it was visible in the constellation of Cancer. At about 17:20 UT on the 25th the asteroid brightened to about apparent magnitude 10.1 while over Southeast Asia, and might have been visible to advanced observers using 10×50 binoculars. But for many locations the asteroid did not get brighter than magnitude 12 before setting and was out of the reach of binoculars.

Identification
The discovery was carried out within the (Data-parallel detection of Solar System objects and space debris) ParaSOL project that is sponsored by UEFISCDI in Romania and led by Marcel Popescu. The new NEA was identified by Costin Boldea and by the STU ParaSOL software pipeline developed by the amateur astronomer Malin Stanescu. Other members of the EURONEAR collaboration who participated in the data analysis were Marian Predatu, and the amateur astronomers Lucian Curelaru and Daniel Bertesteanu.

Description
is approximately 40-90 m in diameter. With an estimated rotation period of about 6 minutes and a lightcurve amplitude of 0.57 magnitudes, the object is suspected of being elongated in shape.

The visible reflectance spectrum of is consistent with that of an X-type asteroid. Being a fast rotator and part of the X-complex, it is highly unlikely to have a carbonaceous-like composition linked to a dark albedo so the size could be in the range 33 to 55 m.

Before the Earth approach, it follows a rather eccentric (0.54), low-inclination (0.08°) orbit of 3.16 years duration, ranging between 0.99 and 3.32 AU from the Sun. It passed Earth on 25 March 2023 which reduces the orbital period to 1098.4 days. It came to perihelion (closest approach to the Sun) on 4 April 2023. Earth is in no short-term danger of having a collision with thanks to a near secular apsidal resonance with Jupiter.

Ruled-out virtual impactors
On 18 March 2023 when the asteroid had an observation arc of 63 days, virtual clones of the asteroid that fit the uncertainty region in the known trajectory showed a 1-in-430 chance that the asteroid could impact Earth on 27 March 2026. Three days later with a 66-day observation arc it was removed from the Sentry Risk Table. It is now known that the nominal approach (line of variation) has the asteroid 0.032 AU ± 900 km from Earth at the time of the potential impact on 27 March 2026. The asteroid will safely approach Earth on 4 April 2026, a week after the potential impact scenario. It was estimated that an impact would produce an upper atmosphere air burst equivalent to 4.5 Mt TNT (19 PJ), roughly equal to 214 of the Fat Man warhead dropped on Nagasaki, or a little over a third of the Tunguska event.

With an observation arc of 63 days it peaked at a Palermo scale rating of –1.17 with the odds of impact then being about 15 times less than the background hazard level.

The early May 2029 approach is not an impact threat as the orbits only intersect in late March.