---
title: "4C +21.35"
url: "https://spacecatalog.org/object/pks-1222-216"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. 4C +21.35 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pks-1222-216"
---

# 4C +21.35

4C +21.35 is a quasar in the constellation [Coma Berenices](https://spacecatalog.org/constellation/coma-berenices), 7.725 Gly from Earth. Other catalogues list it as PKS 1222+216.

It produced gamma rays above a hundred billion electronvolts that varied within ten minutes, which sets two conditions at once: the source has to be small enough to change that fast, and far enough out along the jet that its own radiation does not absorb what it makes.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 7.725 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 4.52 billion years ago.
- **WHERE TO LOOK:** [Coma Berenices](https://spacecatalog.org/constellation/coma-berenices) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| DISTANCE FROM EARTH | 7.725 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Coma Berenices |
| RIGHT ASCENSION (J2000) | 12h 24m 54.5s |
| DECLINATION (J2000) | +21° 22′ 46.4″ |

## Catalogue data

### WHAT KIND OF THING IT IS

What the object is in itself, rather than how it happens to look from here.

| Field | Value |
| --- | --- |
| Accretion state | quasar — a thin disc near its Eddington limit |

### WHERE IT IS AND HOW IT MOVES

Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.

| Field | Value |
| --- | --- |
| Redshift (z) | 0.43201512 |

## Also known as

- Common name: 4C +21.35
- Common name: PKS 1222+216

## Source

[SpaceCatalog curated data](https://spacecatalog.org/releases) — CC-BY-4.0

How this was made: https://spacecatalog.org/methods#source-curated

## Cite this page

SpaceCatalog. 4C +21.35 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pks-1222-216

```bibtex
@misc{spacecatalog_pks-1222-216,
  author       = {{SpaceCatalog}},
  title        = {{4C +21.35}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/pks-1222-216},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}
}
```

SpaceCatalog curated data — CC-BY-4.0

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/pks-1222-216