C/2009 K5
Not currently visible. Last report 5437 days ago at mag 30.6. Historic peak was mag 9.6. 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
30.6
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
421
Arc unknown
Last observation
5437d ago
Fri, 28 Oct 2011 23:16:47 GMT · COBS consensus
Perihelion
2010-04-25
1.420 au
Peak window
2010-04-20 → 2010-04-28
COBS peak mag 9.6 on 2010-04-23 · perihelion 2010-04-25. Window is those dates ±3 days — not a light-curve fit.
Historic peak
9.6
COBS / analyzed peak 2010-04-23
Catalog ingest
11h ago
Venator last wrote this row 2026-09-16 13:20:16 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
1.420 au
e
0.9990
i
104.00°
Ω
258.00°
ω
66.00°
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/2009 K5 (McNaught)
Informal: McNaught
C/2009 K5 · 2026-09-14 18:27:53 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:53 UTC → current
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1–40 of 67
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.