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Comet

Kobayashi

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440P/Kobayashi

Where is it now

Distance from Sun
10.512 AU
True anomaly
149.7°
Distance from Earth
10.538 AU
As of
24 October 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.

Sun Earth — 0.994 AU from the Sun Earth Kobayashi — 10.512 AU from the Sun Kobayashi
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Kobayashi is 10.538 AU from Earth today (1.5 light-hours).

In the sky

Right ascension
20h 01m 35s
Declination
-26° 11′ 23″
Constellation
Sagittarius
Distance from Earth
10.54 AU
Elongation from the Sun
85.54° — well clear of the Sun

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

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

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
8.566 AU
Eccentricity
0.7611
Inclination
12.38°
Orbital period
25.07 years
Perihelion
2.047 AU
Aphelion
15.086 AU
Longitude of ascending node
329.03°
Argument of periapsis
183.29°
Epoch · J2000
2456962.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 411.9 LD
1.0583 AU
Tisserand (Jupiter)
2.233

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
829
Data arc
25.34 years
First observed
30 January 1997
Last observed
3 June 2022
Residual RMS
0.51 ″
Solution · Otto Matic
7 July 2024

Visual & observation

Absolute magnitude (H)
7.4
Total magnitude M₁ · K₁ 32.3
7.4

Discovery & classification

Also known as 440P · 440P/1997 B1 · 440P/2021 W2

Named

Close approaches 4 on record

When (UTC) Body Distance Lunar distances Relative speed
2071-07-22 13:28:00 Juptr 1.2803 AU 498.3 LD 10 km/s
2126-05-27 19:28:00 Juptr 1.0261 AU 399.3 LD 11.4 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources