C/1998 Y1
Not currently visible. Last report 10125 days ago at mag 37.6. Historic peak was mag 15.8. 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
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J2000
Declination
—
J2000
Estimated magnitude
37.6
Professional survey · COBS consensus
Confidence
33
Class E · priority 60
Observations
12
Arc unknown
Last observation
10125d ago
Wed, 17 Feb 1999 14:24:00 GMT · COBS consensus
Perihelion
1998-12-01
1.730 au
Peak window
1998-11-28 → 1998-12-19
COBS peak mag 15.8 on 1998-12-16 · perihelion 1998-12-01. Window is those dates ±3 days — not a light-curve fit.
Historic peak
15.8
COBS / analyzed peak 1998-12-16
Catalog ingest
14h ago
Venator last wrote this row 2026-11-06 14:20:21 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.
No tail measures stored yet for this object.
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
1.730 au
e
0.9250
i
28.30°
Ω
98.70°
ω
340.00°
a
—
MOID
—
H
—
H0 / n
—
NEO score
—
PHA score
—
RMS
—
Elongation
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COBS comet list
okComet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).
C/1998 Y1 (LINEAR)
Informal: LINEAR
C/1998 Y1 · 2026-09-14 18:27:58 UTC → current
Discoverer · parsed-name · 2026-09-14 18:27:58 UTC → current
CCD Observer · NAK01 · 5 reports · last 10125d ago
Seiichi Yoshida and KenIchi Kadota
CCD Observer · YOS05 · 5 reports · last 10135d ago
CCD Observer · YOS04 · 4 reports · last 10135d ago
Visual Observer · HAL · 2 reports · last 10178d ago
CCD Observer · ROQ · 1 reports · last 10175d ago
Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.