---
title: "V0391 Peg b"
url: "https://spacecatalog.org/object/v0391-peg-b"
release: "DR1"
licence: "No licence stated; acknowledgement requested"
citation: "SpaceCatalog. V0391 Peg b [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/v0391-peg-b"
---

# V0391 Peg b

V0391 Peg b is a gas giant in the constellation [Pegasus](https://spacecatalog.org/constellation/pegasus), 3901 ly from Earth. It orbits V0391 Peg at a mean distance of 1.7 AU. It has a mass of 3.20 M♃ and a radius of 1.17 R♃ · 83 553 km. It was discovered in 2007.

## At a glance

- **WHAT IT IS:** Gas giant
- **HOW FAR:** 3901 ly — The light arriving now left it that long ago.
- **HOW BIG:** 1.17 R♃ · 83 553 km — Its radius: half the width across.
- **WHERE TO LOOK:** [Pegasus](https://spacecatalog.org/constellation/pegasus) — The patch of sky it sits in, as seen from Earth.
- **ONE ORBIT TAKES:** 3.2 years — One trip round V0391 Peg.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Gas giant |
| MASS | 3.20 M♃ ±0.7 |
| RADIUS | 1.17 R♃ · 83 553 km |
| DISTANCE FROM EARTH | 3901 ly ±256 — by NASA Exoplanet Archive sy\_dist (TICv8, 2019AJ....158..138S) |
| ORBITS | V0391 Peg |
| SEMI-MAJOR AXIS | 1.7 AU ±0.1 |
| CONSTELLATION | Pegasus |
| RIGHT ASCENSION (J2000) | 22h 04m 12.1s |
| DECLINATION (J2000) | +26° 25′ 07.8″ |
| DISCOVERED | 2007 |

## 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 |
| --- | --- |
| Equilibrium temperature | 519.69 K |
| Host star spectral type | sdBV |
| Host star temperature | 29 300 ±500 K |
| Host star mass | 0.5 M☉ |
| Host star radius | 0.23 ±0.03 R☉ |

### HOW BRIGHT IT IS

What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.

| Field | Value |
| --- | --- |
| Host star apparent magnitude (V) | 14.77 |

### THE ORBIT

The shape of the path, where the object sits on it, and the instant those figures were true of. An orbit is a fit to observations and drifts away from the real one either side of its epoch.

| Field | Value |
| --- | --- |
| Host star | V0391 Peg |
| Orbital period | 3.203 years ±44 |
| Eccentricity | 0 |
| Stars in system | 1 |
| Planets in system | 1 |

### WHEN IT WAS FOUND

Who first saw it, from where, and by what method.

| Field | Value |
| --- | --- |
| Discovery method | Pulsation Timing Variations |
| Discovered at | Multiple Observatories |

## Also known as

- Exoplanet: V0391 Peg b
- Host star: V0391 Peg

## Source

[NASA Exoplanet Archive (Planetary Systems Composite Parameters)](https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PSCompPars) — No licence stated; acknowledgement requested

The producer asks: This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Cite Christiansen et al. (2025), Planetary Science Journal (doi:10.3847/PSJ/ade3c2), and the literature reference given with each value.

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

## Cite this page

SpaceCatalog. V0391 Peg b \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/v0391-peg-b

```bibtex
@misc{spacecatalog_v0391-peg-b,
  author       = {{SpaceCatalog}},
  title        = {{V0391 Peg b}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/v0391-peg-b},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from NASA Exoplanet Archive (Planetary Systems Composite Parameters).}
}
```

NASA Exoplanet Archive (Planetary Systems Composite Parameters) — No licence stated; acknowledgement requested

Acknowledgement the producer asks for: This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Cite Christiansen et al. (2025), Planetary Science Journal (doi:10.3847/PSJ/ade3c2), and the literature reference given with each value.

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/v0391-peg-b