---
title: "K2-391"
url: "https://spacecatalog.org/object/k2-391"
release: "DR1"
licence: "No licence stated; acknowledgement requested"
citation: "SpaceCatalog. K2-391 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/k2-391"
---

# K2-391

K2-391 is a G7 yellow [star](https://spacecatalog.org/stars) in the constellation [Aquarius](https://spacecatalog.org/constellation/aquarius), 1657 ly from Earth, shining at apparent magnitude 12.53 (V).

## At a glance

- **WHAT IT IS:** Yellow star
- **HOW FAR:** 1657 ly — The light arriving now left it that long ago.
- **HOW BRIGHT (V):** 12.53 — A small telescope reaches it.
- **WHERE TO LOOK:** [Aquarius](https://spacecatalog.org/constellation/aquarius) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | G7 yellow star |
| MASS | 0.76 M☉ — NASA Exoplanet Archive composite parameters |
| DISTANCE FROM EARTH | 1657 ly — by NASA Exoplanet Archive sy\_dist (TICv8, 2019AJ....158..138S) |
| APPARENT MAGNITUDE (V) | 12.53 |
| CONSTELLATION | Aquarius |
| RIGHT ASCENSION (J2000) | 23h 44m 54.2s |
| DECLINATION (J2000) | −07° 42′ 05.5″ |

## 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 |
| --- | --- |
| Spectral type | G7 |
| Surface temperature | 5543 K |
| Radius | 0.566 R☉ |
| Mass | 0.757 M☉ |

### 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 |
| --- | --- |
| Stars in system | 1 |
| Planets in system | 1 |

### WHERE THESE FIGURES CAME FROM

Which catalogue, paper or model each of the fields above was read from, where the source named one.

| Field | Value |
| --- | --- |
| Stellar parameters from | NASA Exoplanet Archive composite parameters |

## 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. K2-391 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/k2-391

```bibtex
@misc{spacecatalog_k2-391,
  author       = {{SpaceCatalog}},
  title        = {{K2-391}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/k2-391},
  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/k2-391