Registry · deep sky

K2-138

Star SIMBAD * 78 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: 23h 15m 47.77s
Declination: −10° 50′ 58.9″
Galactic l, b: 64.216, -62.24
Magnitude V: 12.21
Parallax: 4.9437 mas
Redshift z: 3.903e-06
Radial velocity: 1.17 km/s
Proper motion: -1.08, -10.68 mas/yr

Also known as

1 identifiers

K2-138

Published measurements

3 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 4 values

Value	Unit	Uncertainty	Source	Reference	Year
0.891	M_sun	± 0.017	NASA Exoplanet Archive	Vivien et al. 2024	2024
0.916	M_sun	± 0.078	NASA Exoplanet Archive	Hardegree-Ullman et al. 2021	2021
0.935	M_sun	± 0.019	NASA Exoplanet Archive	Lopez et al. 2019	2019
0.93	M_sun	± 0.06	NASA Exoplanet Archive	Christiansen et al. 2018	2018

Radius 5 values

Value	Unit	Uncertainty	Source	Reference	Year
0.834	R_sun	± 0.011	NASA Exoplanet Archive	Vivien et al. 2024	2024
0.839	R_sun	± 0.054	NASA Exoplanet Archive	Hardegree-Ullman et al. 2021	2021
0.863	R_sun	± 0.031	NASA Exoplanet Archive	Lopez et al. 2019	2019
0.86	R_sun	± 0.08	NASA Exoplanet Archive	Christiansen et al. 2018	2018
0.86	R_sun	± 0.05	NASA Exoplanet Archive	ExoFOP	2017

Effective temperature 5 values

Value	Unit	Uncertainty	Source	Reference	Year
5,354.7	K	± 27.9	NASA Exoplanet Archive	Vivien et al. 2024	2024
5,283	K	± 122	NASA Exoplanet Archive	Hardegree-Ullman et al. 2021	2021
5,356.3	K	± 41.8	NASA Exoplanet Archive	Lopez et al. 2019	2019
5,378	K	± 60	NASA Exoplanet Archive	Christiansen et al. 2018	2018
5,281	K	± 128.8	NASA Exoplanet Archive	ExoFOP	2017

Related objects

Object	Type	Relation
K2-138 b	Exoplanet	host
K2-138 c	Exoplanet	host
K2-138 d	Exoplanet	host
K2-138 e	Exoplanet	host
K2-138 f	Exoplanet	host
K2-138 g	Exoplanet	host

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
K2-138 b	Exoplanet	0.1661″	12.25
K2-138 g	Exoplanet	0.1661″	12.25
K2-138 d	Exoplanet	0.1661″	12.25
K2-138 e	Exoplanet	0.1661″	12.25
K2-138 f	Exoplanet	0.1661″	12.25
K2-138 c	Exoplanet	0.1661″	12.25
HD 219432	HighPM*	176.9″	9.24
HD 219403	Star	215.1″	10.03
G 157-38	HighPM*	359.6″	12.56
UCAC2 28123519	Star	440.7″	12.01
LEDA 195297	Galaxy	456.9″	—

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/k2-138-8949349 · Registry entry updated 2026-08-14.