HD 219666

Name	Orbital Separation	Planet Size	Method	Year	Reference	Disposition
HD 219666
HD 219666 b	6.03 d	4.9 R_⨁	Transit	2018	Esposito et al. 2019	Confirmed Planet

HD 219666 Stellar Parameters (6 Solutions)

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RA: 23h18m14.22s

Dec: -56d54m14.35s

Distance: 94.1719+0.2518-0.2506
pc

Parallax: 10.5900000±0.0281131 mas

Ecliptic Latitude: -46.82486 deg

Ecliptic Longitude: 321.7008 deg

Galactic Latitude: -55.92883 deg

Galactic Longitude: 325.60907 deg

Total Proper Motion: 314.5657803±0.0388329 mas/yr

Proper Motion (RA): 313.9180000±0.0388128 mas/yr

Proper Motion (Dec): -20.1772000±0.0434263 mas/yr

Photometry: m_V
9.809±0.003; m_TESS
9.179±0.006; m_J
8.557±0.020; m_H
8.254±0.042; m_Ks
8.158±0.033; m_W1
8.080±0.023; m_W2
8.138±0.020; m_W3
8.100±0.021; m_W4
8.250±0.288; m_Gaia
9.649560±0.000219; m_B
10.596±0.037

Tools: Planetary Systems; ExoFOP Target Overview Page; IRSA Finding Chart; TOI; Stellar Hosts

Source	Murphy et al. 2025	Oddo et al. 2023	TICv8	Esposito et al. 2019	Gaia DR2	ExoFOP
T_eff (K)	5540±63	5527±65	5527.000+103.188-149.639	5527±65	5493.5+326.5-114.5	5586±187
L_✶ (log₁₀(L_⦿))	---	---	-0.03158131+0.01031588-0.00981525	---	-0.02779837+0.00188799-0.00189624	---
γ (km/s)	---	---	---	-20.0976±0.0004	-19.956535824233089±0.307659426052417	---
R_✶ (R_⦿)	1.059±0.008	1.03±0.03	1.0516800+0.0651176-0.0447819	1.03±0.03	1.0691907+0.0459909-0.1165975	1.05±0.05
Metallicity (dex)	---	0.04±0.04 [Fe/H]	---	0.04±0.04 [Fe/H]	---	---
v sin i (km/s)	---	---	---	2.2±0.8	---	---
Age (Gyr)	---	10.0±2.0	---	10±2	---	---
M_✶ (M_⦿)	1.02±0.10	0.92±0.03	0.97000000+0.15527900-0.08659840	0.92±0.03	---	---
log g (log₁₀(cm/s²))	---	4.40±0.11	4.3810700+0.0775376-0.0826475	4.40±0.11	---	4.367630±0.270247
ρ_✶ (g/cm³)	---	---	1.1756781+0.2958365-0.2290347	---	---	---
CAII LOG RHK	---	-5.07±0.03	---	---	---	---
Sp. T	---	G5 V	---	---	---	---

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HD 219666 b Planetary Parameters (6 Solutions)

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Status: Confirmed Planet

Detected By: Radial Velocity, Transit

Tools: Planetary Systems; Transit Prediction Service; TOI; Transit; Atmospheric Spectroscopy

Source	Murphy et al. 2025	Oddo et al. 2023	Kokori et al. 2023	Patel & Espinoza 2022	Esposito et al. 2019	ExoFOP
a/R_✶	13.25±0.46	21.747±2.023	13.3±0.4	14.56+3.10-1.73	13.27±0.39	---
T_eq (K)	1076±22	838±40	---	---	1073±20	1377.9182059038767
b	---	0.402±0.193	---	0.805+0.048-0.104	0.838+0.012-0.013	---
M_p (M_⨁)	17.6±1.2	---	---	---	16.6±1.3	---
M_p (M_Jup)	0.055±0.003	---	---	---	0.0522±0.0041	---
e	0.05±0.04	---	---	---	0	---
i (deg)	86.42±0.23	88.938±0.505	86.38±0.15	---	86.38±0.15	---
P (days)	6.034468±0.000004	6.04345±0.00001	6.034468±0.000014	6.0357970+0.0003070-0.0000160	6.03607+0.00064-0.00063	6.034463389519887±0.000003480968999
ρ (g/cm³)	---	---	---	---	0.87+0.12-0.11	---
R_p (R_⨁)	4.898±0.060	4.24±0.16	---	---	4.71±0.17	4.6585116968609483±0.2636656496761463
R_p (R_Jup)	0.437±0.006	0.378±0.014	---	---	0.420±0.015	0.41560529200134572±0.02352271421755113
R_p/R_✶	0.0421±0.0006	0.0376±0.0009	0.0419±0.0008	0.0397±0.0017	0.04192±0.00083	---
K (m/s)	6.07±0.32	---	---	---	6.17±0.46	---
a (au)	---	0.104±0.005	---	---	0.06356±0.00265	---
T₁₄ (hours)	---	2.028±0.194	---	---	2.158±0.034	2.0529009652903087±0.3050467396281544
T_C (days)	2459083.5107±0.0001 (BJD-TDB)	2459083.5109±0.0011 (BJD)	2458600.75321±0.00081 (BJD-TDB)	2459083.67430+0.03780-0.00190 (BJD)	2458329.1996±0.0012 (BJD-TDB)	2460899.883842000±0.000827461 (BJD)
δ (%)	---	0.1414±0.0068	---	---	---	0.175064576320074±0.005030583047754
ω (deg)	0.0±48.0	---	---	---	---	---
S (S_⨁)	---	---	---	---	---	598.44079934639

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Nearby Data (within 30 arcseconds) Browse Nearby Data

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Known Objects: 1 Confirmed Planets; 1 2MASS Point Source Catalog

Data Files: 1 SuperWASP Time Series; 1 Associated Literature Data

Bibliography (11 References)

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HST Transmission Spectra of the Hot Neptune HD 219666 b: Detection of Water and the Challenge of Constraining Both Water and Methane
Murphy et al. 2025 Reference Overview
Exploring the Ability of Hubble Space Telescope WFC3 G141 to Uncover Trends in Populations of Exoplanet Atmospheres through a Homogeneous Transmission Survey of 70 Gaseous Planets
Edwards et al. 2023 Reference Overview
ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations
Kokori et al. 2023 Reference Overview
Characterization of a Set of Small Planets with TESS and CHEOPS and an Analysis of Photometric Performance
Oddo et al. 2023 Reference Overview
Empirical Limb-darkening Coefficients and Transit Parameters of Known Exoplanets from TESS
Patel & Espinoza 2022 Reference Overview
The Revised TESS Input Catalog and Candidate Target List
TICv8 Reference Overview
HD 219666 b: a hot-Neptune from TESS Sector 1
Esposito et al. 2019 Reference Overview
Gaia Data Release 2
Gaia DR2 Reference Overview
ExoFOP TOI Table
ExoFOP
All WISE Data Release
Cutri et al. 2014 Reference Overview
2MASS All-Sky Catalog of Point Sources
2MASS Point Source Catalog Reference Overview

Legend

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System
Star
Confirmed
Candidate
False Positive Planet
Controversial
False Positive

Aliases
Data Access
Transit Prediction Service
Time Series
Kepler | K2

External Link
Search
Browse
Download

Debug Info

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https://vmexoweb2.ipac.caltech.edu/data/Overviews_2.0/7/HD_219666.json

Catalog Parameters

RA

ra

23h18m14.22s

Dec

dec

-56d54m14.35s

β

elat

-46.82486

λ

elon

321.7008

b

glat

-55.92883

l

glon

325.60907

m_V

sy_vmag

9.809±0.003

m_TESS

sy_tmag

9.179±0.006

m_J

sy_jmag

8.557±0.020

m_H

sy_hmag

8.254±0.042

m_Ks

sy_kmag

8.158±0.033

sy_kepmag

no_data

m_W1

sy_w1mag

8.080±0.023

m_W2

sy_w2mag

8.138±0.020

m_W3

sy_w3mag

8.100±0.021

m_W4

sy_w4mag

8.250±0.288

sy_icmag

no_data

m_Gaia

sy_gaiamag

9.649560±0.000219

m_B

sy_bmag

10.596±0.037

sy_gmag

no_data

sy_imag

no_data

sy_rmag

no_data

sy_umag

no_data

sy_zmag

no_data

μ

sy_pm

314.5657803±0.0388329

μ_δ

sy_pmdec

-20.1772000±0.0434263

μ_α

sy_pmra

313.9180000±0.0388128

π

sy_plx

10.5900000±0.0281131

Distance

sy_dist

94.1719+0.2518-0.2506

Set Parameters

R_✶

st_rad

1.0691907+0.0459909-0.1165975

T_eff

st_teff

5493.5+326.5-114.5

HD 219666 Overview

HD 219666 Architecture & Discovery Information

HD 219666