---
title: "The HD 101581 system"
url: "https://spacecatalog.org/system/hd-101581"
release: "DR1"
licence: "No licence stated; acknowledgement requested"
citation: "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 HD 101581 system

HD 101581 is a K5V orange dwarf in Centaurus, 40.45 ly away, with 2 known planets. Their orbits run from 0.0460 to 0.0573 AU. All of them were detected by transit.

## The planets, innermost first

| Planet | Orbit (AU) | Period | Radius | Mass | Equilibrium T |
| --- | --- | --- | --- | --- | --- |
| [b](https://spacecatalog.org/object/hd-101581-b) | 0.0460 | 4.466 d | 0.96 R⊕ | 0.827 M⊕ | 834 K |
| [c](https://spacecatalog.org/object/hd-101581-c) | 0.0573 | 6.204 d | 0.99 R⊕ | 0.937 M⊕ | 747 K |

Every figure is the planet's composite parameter from the [NASA Exoplanet Archive (Planetary Systems Composite Parameters)](https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PSCompPars), one consistent set per world. Semi-major axes are orbits about the star, not distances from Earth.

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 host star

| Quantity | Value |
| --- | --- |
| CLASS | K5V orange dwarf |
| SPECTRAL TYPE | K5V |
| SURFACE TEMPERATURE | 4600 K |
| LUMINOSITY | 0.104 L☉ |
| DISTANCE FROM EARTH | 40.45 ly |
| APPARENT MAGNITUDE | 7.77 |
| CONSTELLATION | Centaurus |

The star itself: https://spacecatalog.org/object/hd-101581

The page itself, with the orbits drawn: https://spacecatalog.org/system/hd-101581