2020 SW

2020 SW
Discovery [1][2]
Discovered byMt. Lemmon Survey
(Kacper W. Wierzchoś)[3]
Discovery siteMt. Lemmon Obs.
Discovery date18 September 2020
Designations
2020 SW
C378AD2 [4][5]
NEO · Apollo (pre-flyby) [6]
Aten (post-flyby) [2]
Orbital characteristics [6]
Epoch 17 December 2020 (JD 2459200.5)
Uncertainty parameter 5
Observation arc6 days
Aphelion1.140 AU
Perihelion0.7425 AU
0.941 AU
Eccentricity0.21118
0.91 yr
353.718°
1° 4m 45.117s / day
Inclination2.326°
1.808°
22 December 2020 19:43 UT
118.950°
Earth MOID0.00042 AU (63,000 km)
Physical characteristics
4–9 m (assumed albedo 0.05–0.25)[7]
0.0079039±0.0000001 h[3]
(28.4540±0.0004 s)
21.4 (at discovery)[1]
29.063±0.335[6]
29.06[2]

2020 SW is a tiny near-Earth asteroid discovered by the Mount Lemmon Survey on 18 September 2020, six days before it made its closest approach to Earth. The asteroid passed within 21,600 kilometres (13,400 mi) from Earth's surface on 24 September 2020 11:13 UT, within the geostationary altitude of 36,000 kilometres (22,000 mi). The encounter with Earth perturbed the asteroid's heliocentric trajectory from an Apollo-type orbit to an Aten-type orbit with a semi-major axis within one astronomical unit from the Sun. As a result, the asteroid will not make any close approaches to Earth within 0.01 astronomical units (4 LD) in the next 200 years.

With an estimated diameter roughly 4–9 metres (13–30 ft) across, 2020 SW is comparable to the size of a small school bus. Had it impacted Earth, it would mostly have disintegrated as a fireball during atmospheric entry and might have left a common strewn field. Extensive observations of its brightness during the close encounter show that it is an elongated body with a rapid rotation period of 28.5 seconds.

  1. ^ a b Cite error: The named reference MPEC-2020-S83 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference MPB-48-1 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference NEO-Exchange was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference PseudoMPEC was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference jpldata was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference sizemagnitude was invoked but never defined (see the help page).