Apophis
99942 Apophis, 2004 MN4
Apophis
Asteroid
Aries
Visible
Level 6
Professional/Research - Timing dependent
Properties
Magnitude
19.1
Type: Asteroid
Distance: 0.922 AU
Orbital Period: 323.6 days
Diameter: 0 km
On April 13, 2029, Apophis will pass within 31,600 km of Earth — closer than geostationary satellites — becoming visible to the naked eye at magnitude ~3. This is a once-in-a-millennium close approach for an asteroid of this size. Named after the Egyptian god of chaos.
Position & Identifiers
RA
02h 49m 56.8s
Dec
+14° 23' 09.6"
Constellation
Aries
Catalog
Apophis
Physical Properties
Diameter
0 km
Mass
4.0e10 kg
Albedo
0.35
(35% reflected)
Rotation
30.4 hours
Angular Size
0.0″ (current)
Orbital Properties
Semi-major Axis
0.9224 AU
(138.0 million km)
Eccentricity
0.1912
Inclination
3.34°
Orbital Period
323.6 days
Distance
1.521 AU
(12.7 light-min)
Elongation
38.3°
Moderate
Observing Tips
Best Months
April
Visibility
Large telescope; naked eye during April 2029 flyby
Where to Look
Near-Earth asteroid (Aten group)
Notes
On April 13, 2029, Apophis will pass within 31,600 km of Earth — closer than geostationary satellites — becoming visible to the naked eye at magnitude ~3. This is a once-in-a-millennium close approach for an asteroid of this size. Named after the Egyptian god of chaos.
Discovery
Discovered by
Roy Tucker, David Tholen, Fabrizio Bernardi
Date
2004-06-19
Current Ephemeris
1.521
AU from Earth
227.5M
km
0.0″
Angular Size
38°
Elongation
Visibility
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