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C/2011 L4

C/2011 L4 (PANSTARRS)

CometClass Ecatalogued
Unknown

Not currently visible. Last report 4114 days ago at mag 28.0. Historic peak was mag 0.5. Typical backyard telescopes will not show it. HST, JWST, or an 8–10 m class telescope might recover it with a good ephemeris.

Active comet in COBS

Right ascension

J2000

Declination

J2000

Estimated magnitude

28.0

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

1090

Arc unknown

Last observation

4114d ago

Fri, 12 Jun 2015 16:33:35 GMT · COBS consensus

Perihelion

2013-03-11

0.303 au

Peak window

2013-03-08 → 2013-03-14

COBS peak mag 0.5 on 2013-03-11 · perihelion 2013-03-11. Window is those dates ±3 days — not a light-curve fit.

Historic peak

0.5

COBS / analyzed peak 2013-03-11

Catalog ingest

9h ago

Venator last wrote this row 2026-09-16 13:20:17 UTC

Light curve

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.

Orbital elements

q

0.303 au

e

1.0000

i

84.90°

Ω

65.10°

ω

334.00°

a

MOID

H

H0 / n

NEO score

PHA score

RMS

Elongation

Reporting sources

  • COBS comet list

    ok

    Comet Observation Database magnitudes and perihelion data for the full COBS list (active and inactive).

Name history

  • C/2011 L4 (PANSTARRS)

    Informal: PANSTARRS

    C/2011 L4 · 2026-09-14 18:27:55 UTC → current

Discoverers

  • PANSTARRS

    Discoverer · parsed-name · 2026-09-14 18:27:55 UTC → current

Contributors

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Pips are observation weight on this object (log of report count). Hover for catalog-wide weight.