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C/2015 P3

C/2015 P3 (SWAN)

CometClass Ecatalogued
Unknown

Not currently visible. Last report 4024 days ago at mag 36.9. Historic peak was mag 14.1. 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

36.9

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

16

Arc unknown

Last observation

4024d ago

Fri, 11 Sep 2015 10:47:59 GMT · COBS consensus

Perihelion

2015-07-24

0.732 au

Peak window

2015-07-21 → 2015-08-03

COBS peak mag 14.1 on 2015-07-31 · perihelion 2015-07-24. Window is those dates ±3 days — not a light-curve fit.

Historic peak

14.1

COBS / analyzed peak 2015-07-31

Catalog ingest

12h 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.

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.

Orbital elements

q

0.732 au

e

0.9970

i

58.10°

Ω

88.30°

ω

133.00°

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/2015 P3 (SWAN)

    Informal: SWAN

    C/2015 P3 · 2026-09-14 18:27:57 UTC → current

Discoverers

  • SWAN

    Discoverer · parsed-name · 2026-09-14 18:27:57 UTC → current

Contributors

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