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C/2023 A2

C/2023 A2 (SWAN)

CometClass Ecatalogued
Unknown

Not currently visible. Last report 1295 days ago at mag 29.9. Historic peak was mag 14.5. 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

29.9

Professional survey · COBS consensus

Confidence

33

Class E · priority 60

Observations

3

Arc unknown

Last observation

1295d ago

Thu, 02 Mar 2023 03:40:00 GMT · COBS consensus

Perihelion

2023-01-20

0.944 au

Peak window

2023-01-13 → 2023-01-23

COBS peak mag 14.5 on 2023-01-16 · perihelion 2023-01-20. Window is those dates ±3 days — not a light-curve fit.

Historic peak

14.5

COBS / analyzed peak 2023-01-16

Catalog ingest

12h ago

Venator last wrote this row 2026-09-16 13:20:19 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

0.944 au

e

0.9980

i

94.70°

Ω

94.50°

ω

142.00°

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/2023 A2 (SWAN)

    Informal: SWAN

    C/2023 A2 · 2026-09-14 18:28:01 UTC → current

Discoverers

  • SWAN

    Discoverer · parsed-name · 2026-09-14 18:28:01 UTC → current

Contributors

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