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Solar
Comet Near-Earth

Kowalski

C/2011 S2 (Kowalski)

Where is it now

Distance from Sun
25.04 AU
True anomaly
168.83°
As of
17 September 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

In the sky

Right ascension
19h 13m 09s
Declination
-22° 03′ 29″
Constellation
Sagittarius
Distance from Earth
24.66 AU
Elongation from the Sun
111.33° — well clear of the Sun

Favours the southern hemisphere; low or below the horizon from far north.

From your location

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Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
16.306 AU
Eccentricity
0.9316
Inclination
17.57°
Orbital period
65.85 years
Perihelion
1.115 AU
Aphelion
31.498 AU
Longitude of ascending node
288.07°
Argument of periapsis
192.19°
Epoch · J2000
2455857.5
Orbit class · HTC
Halley-type comet
Earth MOID · 53.6 LD
0.1378 AU
Tisserand (Jupiter)
1.546

Orbit quality

Orbit reasonably well determined (uncertainty code 4).

Observations used
343
Data arc
180 days
First observed
30 September 2011
Last observed
28 March 2012
Residual RMS
0.67 ″
Solution · Otto Matic
15 April 2021

Visual & observation

Absolute magnitude (H)
15.6
Total magnitude M₁ · K₁ 4.5
15.6

Discovery & classification

Also known as 2011 S2

Near-Earth Object Named

Sources