2021 TP21

2021 TP21
Discovery[1]
Discovered byMount Lemmon Survey
Discovery date11 October 2021
Designations
2021 TP21
Orbital characteristics[2]
Epoch 2021-Jul-01 (JD 2459396.5)
Uncertainty parameter 6
Observation arc57 days
Aphelion4.2274 AU (Q)
Perihelion0.81425 AU (q)
2.5208 AU (a)
Eccentricity0.67699 (e)
4.00 years
318.4° (M)
Inclination25.404° (i)
8.089° (Ω)
116.3° (ω)
Earth MOID0.03 AU (4.5 million km)
Jupiter MOID1.7 AU (250 million km)
Physical characteristics
Dimensions
  • ~300 m (1,000 ft)[3]
  • 240–540 meters
20.2[2][4]

2021 TP21 is an Apophis-sized asteroid that was discovered on 11 October 2021 when it was 0.5 AU (75 million km) from Earth.[1] This potentially hazardous asteroid (PHA) spends most or its orbit closer to 4 AU (600 million km) from the Sun as objects orbit more slowly when near aphelion (furthest distance from the Sun). 2021 TP21 was rated with a Torino scale of 1 from 31 October 2021 to 4 November 2021 for a potential impact on 27 March 2081.[3] As the observation arc became longer the nominal distance from Earth became further on the potential impact date.

Nominal approach getting further from Earth with longer observation arc
(27 March 2081 virtual impactor)
Observation
arc
(in days) 		JPL Horizons
nominal geocentric
distance (AU) 		uncertainty
region
(3-sigma) 		Impact
probability
(1 in) 		Torino
scale
17 0.17 AU (25 million km)[5] ± 1.5 billion km[5] 100000 0
19 1.4 AU (210 million km)[6] ± 870 million km[6] 50000[3] 1[3]
57 2.5 AU (370 million km)[7] ± 18 million km[7] 0 0
  1. ^ a b Cite error: The named reference MPEC2021-U10 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference jpldata was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference risk was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference arc17 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference arc19 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference arc57 was invoked but never defined (see the help page).