---
title: "MXB 1658-298 b"
url: "https://spacecatalog.org/object/mxb-1658-298-b"
release: "DR1"
licence: "No licence stated; acknowledgement requested"
citation: "SpaceCatalog. MXB 1658-298 b [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/mxb-1658-298-b"
---

# MXB 1658-298 b

MXB 1658-298 b is a gas giant in the constellation [Ophiuchus](https://spacecatalog.org/constellation/ophiuchus). It orbits MXB 1658-298 at a mean distance of 1.613 AU. It has a mass of 23.70 M♃ and a radius of 1.07 R♃ · 76 537 km. It was discovered in 2017.

## At a glance

- **WHAT IT IS:** Gas giant
- **HOW FAR:** 1.613 AU — Its average distance from MXB 1658-298, not from Earth.
- **HOW BIG:** 1.07 R♃ · 76 537 km — Its radius: half the width across.
- **WHERE TO LOOK:** [Ophiuchus](https://spacecatalog.org/constellation/ophiuchus) — The patch of sky it sits in, as seen from Earth.
- **ONE ORBIT TAKES:** 760 days — One trip round MXB 1658-298.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Gas giant |
| MASS | 23.70 M♃ ±3.2 |
| RADIUS | 1.07 R♃ · 76 537 km |
| ORBITS | MXB 1658-298 |
| SEMI-MAJOR AXIS | 1.613 AU ±0.11 |
| CONSTELLATION | Ophiuchus |
| RIGHT ASCENSION (J2000) | 17h 02m 06.5s |
| DECLINATION (J2000) | −29° 56′ 44.1″ |
| 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 |
| --- | --- |
| Host star mass | 1.98 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 |
| --- | --- |
| Host star | MXB 1658-298 |
| Orbital period | 760 days |
| Stars in system | 2 |
| Planets in system | 1 |

### WHEN IT WAS FOUND

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

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

## Also known as

- Exoplanet: MXB 1658-298 b
- Host star: MXB 1658-298

## 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. MXB 1658-298 b \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/mxb-1658-298-b

```bibtex
@misc{spacecatalog_mxb-1658-298-b,
  author       = {{SpaceCatalog}},
  title        = {{MXB 1658-298 b}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/mxb-1658-298-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/mxb-1658-298-b