C/2003 K4
Not currently visible. Last report 7512 days ago at mag 28.0. Historic peak was mag 5.1. Typical backyard telescopes will not show it. HST, JWST, or an 8–10 m class telescope might recover it with a good ephemeris.
Right ascension
—
J2000
Declination
—
J2000
Estimated magnitude
28.0
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
1324
Arc unknown
Last observation
7513d ago
Tue, 21 Feb 2006 10:33:36 GMT · COBS consensus
Perihelion
2004-10-02
1.020 au
Peak window
2004-09-29 → 2004-10-05
COBS peak mag 5.1 on 2004-10-02 · perihelion 2004-10-02. Window is those dates ±3 days — not a light-curve fit.
Historic peak
5.1
COBS / analyzed peak 2004-10-02
Catalog ingest
9h ago
Venator last wrote this row 2026-09-16 13:20:15 UTC
Brightness over time (V mag)
Gold = reported observations. Steel dashed family = ensemble (nominal / outburst / fade / disruption).
Tail length
Converted to degrees from COBS (d / arcmin / arcsec). Empty until analysis has pulled the archive.
Ensemble is a first-pass H0/n photometric model plus observed samples — not a trained ML forecast yet. The background analyzer walks the catalog one object at a time so COBS is not flooded. Disruption track rises after perihelion to stand in for solar-wind stripping.
q
1.020 au
e
1.0000
i
134.00°
Ω
18.70°
ω
198.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
—
COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/2003 K4 (LINEAR)
Informal: LINEAR
C/2003 K4 · 2026-09-14 18:27:52 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:52 UTC → current
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Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.