---
title: "1I/'Oumuamua"
url: "https://spacecatalog.org/object/2017-u1-oumuamua"
release: "DR1"
licence: "No licence stated; citation requested"
citation: "SpaceCatalog. 1I/'Oumuamua [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/2017-u1-oumuamua"
---

# 1I/'Oumuamua

1I/'Oumuamua is a hyperbolic [asteroid](https://spacecatalog.org/asteroids). Its orbit does not close: it passes within 0.255912 AU of the [Sun](https://spacecatalog.org/object/sun) once and never returns. Its absolute magnitude (H) is 22.08. Other catalogues list it as 2017 U1 and 'Oumuamua (A/2017 U1). It was discovered in 2017.

The first object seen passing through the Solar System from interstellar space, found on its way out in October 2017. It showed no coma, tumbled rather than spun, and its brightness swung by a factor of ten as it turned — which is why it is usually drawn as an elongated shard, though the shape was inferred from the light curve and never resolved.

## At a glance

- **WHAT IT IS:** Hyperbolic asteroid
- **HOW BRIGHT IN ITSELF (H):** 22.08 — How bright it would look from a fixed, standard distance — a measure of the object rather than of the view from here.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Hyperbolic asteroid |
| ORBITS | Sun |
| PERIHELION | 0.255912 AU ±6.7×10⁻⁶ |
| ORBIT | hyperbolic — unbound |
| ABSOLUTE MAGNITUDE (H) | 22.08 |
| DISCOVERED | 2017 |

## 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 |
| --- | --- |
| Rotation period | 7.937 hours |

### 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 |
| --- | --- |
| Eccentricity | 1.20113 ±2.1×10⁻⁵ |
| Hyperbolic excess velocity | 26.41 km/s |
| Inclination | 122.74° |
| Longitude of ascending node | 24.6° |
| Argument of perihelion | 241.81° |
| Mean anomaly | 51.16° |
| Element epoch | 2458080.5000 JD |
| Perihelion passage | 2458006.0073 JD |
| Minimum distance from Earth's orbit | 0.0958212 AU |
| Orbit class | HYA |

### WHEN IT WAS FOUND

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

| Field | Value |
| --- | --- |
| First observed | 2017-10-14 |

## Also known as

- Asteroid: 2017 U1
- Asteroid: 'Oumuamua (A/2017 U1)
- Common name: 'Oumuamua
- Interstellar: 1I
- Interstellar: 1I/'Oumuamua

## Source

[JPL Small-Body Database](https://ssd.jpl.nasa.gov/tools/sbdb_query.html) — No licence stated; citation requested

The producer asks: Solar System Dynamics. (Downloaded 2026, October 1). Small-Body Database Query. https://ssd.jpl.nasa.gov

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

## Cite this page

SpaceCatalog. 1I/'Oumuamua \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/2017-u1-oumuamua

```bibtex
@misc{spacecatalog_2017-u1-oumuamua,
  author       = {{SpaceCatalog}},
  title        = {{1I/'Oumuamua}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/2017-u1-oumuamua},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from JPL Small-Body Database.}
}
```

JPL Small-Body Database — No licence stated; citation requested

Acknowledgement the producer asks for: Solar System Dynamics. (Downloaded 2026, October 1). Small-Body Database Query. https://ssd.jpl.nasa.gov

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/2017-u1-oumuamua