Registry · exoplanet

HD 128311 b

Exoplanet 76 papers

harvesting The full record is being pulled from the archives right now — measurement tables, the Gaia row, catalogue photometry. This page will fill itself in.

Right ascension: 14h 36m 00.78s
Declination: +09° 44′ 43.6″
Galactic l, b: 2.7292, 59.84
Magnitude V: 7.48
Distance: 16.329 pc

Also known as

1 identifiers

HD 128311b

Planet

NASA Exoplanet Archive, composite parameters

Host star	HD 128311 · K3V
Discovery	Radial Velocity, 2002 · W. M. Keck Observatory
Orbital period	453.019 d
Semi-major axis	1.084 au
Eccentricity	0.303
Radius	13.5 R⊕ · 1.2 R♃
Mass	562.24 M⊕ · 1.769 M♃
Density	1.26 g/cm³
Equilibrium temperature	200.47 K
System distance	16.329 pc

Published measurements

4 quantities measured more than once

One object can carry a dozen published estimates of the same quantity. The register keeps them side by side rather than picking a winner — the citation is part of the value.

Mass 6 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
635.6568	M_earth	± 50.85	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
581.6	M_earth	± 47.67	Radial Velocity	NASA Exoplanet Archive	Rein 2015	2015
562.2413	M_earth	± 7.31	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2014	2014
460.83	M_earth	± 41.32	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2009	2009
692.84	M_earth	± 69.92	Radial Velocity	NASA Exoplanet Archive	Vogt et al. 2005	2005
816.79	M_earth		Radial Velocity	NASA Exoplanet Archive	Butler et al. 2003	2003

Orbital period 6 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
453.28	d	± 0.69	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
460.1	d	± 4.2	Radial Velocity	NASA Exoplanet Archive	Rein 2015	2015
453.019	d	± 0.404	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2014	2014
454.2	d	± 1.6	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2009	2009
458.6	d	± 6.8	Radial Velocity	NASA Exoplanet Archive	Vogt et al. 2005	2005
422	d	± 10	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2003	2003

Semi-major axis 5 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1.088	au	± 0.012	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
1.084	au	± 0.006	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2014	2014
1.086	au	± 0.008	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2009	2009
1.099	au	± 0.04	Radial Velocity	NASA Exoplanet Archive	Vogt et al. 2005	2005
1.02	au		Radial Velocity	NASA Exoplanet Archive	Butler et al. 2003	2003

Eccentricity 6 values

Value	Uncertainty	Band / method	Source	Reference	Year
0.283	± 0.04	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.3	± 0.03	Radial Velocity	NASA Exoplanet Archive	Rein 2015	2015
0.303	± 0.011	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2014	2014
0.345	± 0.049	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2009	2009
0.25	± 0.1	Radial Velocity	NASA Exoplanet Archive	Vogt et al. 2005	2005
0.31	± 0.1	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2003	2003

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
HD 128311 c	Exoplanet	0″	7.48
HD 128311	BYDraV*	5.015″	7.446
SDSS J143548.70+094331.6	QSO	192.4″	—
SDSS J143528.46+094334.0	QSO	482.6″	20.83

Provenance

where this card came from

Archive	Read at (UTC)	Record
Seeded from the bulk archive load; no per-object fetch yet.

Machine-readable: /api/v1/object/hd-128311-b · Registry entry updated 2026-08-14.