---
title: "Groombridge 1830"
url: "https://spacecatalog.org/object/groombridge-1830"
release: "DR1"
licence: "CC-BY-SA-4.0"
citation: "SpaceCatalog. Groombridge 1830 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/groombridge-1830"
---

# Groombridge 1830

Groombridge 1830 is a K1V\_Fe-1.5 orange dwarf in the constellation [Ursa Major](https://spacecatalog.org/constellation/ursa-major), 29.65 ly from Earth, shining at apparent magnitude 6.42 (V). Other catalogues list it as GJ 451, Gl 451A and HD 103095, among 7 designations in total.

## At a glance

- **WHAT IT IS:** Orange dwarf
- **HOW FAR:** 29.65 ly — The light arriving now left it that long ago.
- **HOW BRIGHT (V):** 6.42 — Bright enough for the naked eye, under a sky dark enough.
- **WHERE TO LOOK:** [Ursa Major](https://spacecatalog.org/constellation/ursa-major) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | K1V\_Fe-1.5 orange dwarf |
| DISTANCE FROM EARTH | 29.65 ly — by parallax |
| APPARENT MAGNITUDE (V) | 6.42 |
| ABSOLUTE MAGNITUDE (V) | 6.63 |
| CONSTELLATION | Ursa Major |
| RIGHT ASCENSION (J2000) | 11h 52m 58.2s |
| DECLINATION (J2000) | +37° 43′ 07.2″ |

## 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 | K1V\_Fe-1.5 |
| Surface temperature | 5043 K |
| Luminosity (visual) | 0.194626 L☉ |
| Luminosity (bolometric) | 0.2275 L☉ |
| Radius | 0.628 R☉ |
| Surface gravity (log g) | 4.627 |
| Metallicity (\[Fe/H\]) | −1.35 ±0.12 |
| Variability | UV Ceti flare star |
| Variability type (GCVS) | UV: |

### 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 |
| --- | --- |
| Colour index (B−V) | 0.754 |
| Variable magnitude, brightest | 6.41 |
| Variable magnitude, faintest | 6.55 |

### 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 |
| --- | --- |
| Proper motion (RA) | 4003.69 mas/yr |
| Proper motion (Dec) | −5813 mas/yr |
| Radial velocity | −99.1 km/s |

### OTHER NAMES AND NUMBERS

The identifiers other catalogues file this object under, for anyone joining this data to theirs.

| Field | Value |
| --- | --- |
| Also known as | Argelander's Star, CF Ursae Majoris |
| Variable-star designation | CF UMa |
| Wikidata item | Q1154100 |
| Wikipedia article | Groombridge 1830 |

### 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 |
| --- | --- |
| Spectral type from | SIMBAD (2003AJ....126.2048G, quality C) |
| Stellar parameters from | Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) |
| Metallicity from | Median of 46 spectroscopic determinations in 55 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them |

## Also known as

- Common name: Groombridge 1830
- Gliese: GJ 451
- Gliese: Gl 451A
- HD: HD 103095
- HIP: HIP 57939
- HR: HR 4550
- Variable star: CF UMa

## Source

[HYG Database v4.1](https://github.com/astronexus/HYG-Database) — CC-BY-SA-4.0

The producer asks: HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.

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

## Cite this page

SpaceCatalog. Groombridge 1830 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/groombridge-1830

```bibtex
@misc{spacecatalog_groombridge-1830,
  author       = {{SpaceCatalog}},
  title        = {{Groombridge 1830}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/groombridge-1830},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}
}
```

HYG Database v4.1 — CC-BY-SA-4.0

Acknowledgement the producer asks for: HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/groombridge-1830