Key parameters at a glance

A radius of 13.85 Earth radii
A mass of 266.02 Earth masses
Surface gravity around 1.39 g
An orbital period of 1.915 days
Semi-major axis 0.0312 AU
Equilibrium temperature 1,746 K (1473 °C)
Distance from Earth 2,083.16 light-years
Earth Similarity Index 0.071
Travel time at Voyager 1 speed 36,736,496 years

HATS-9 b Planet Profile

Physical Specs

Radius

13.85 R⊕

Radius (Jupiter)

1.236 R♃

Mass

266.02 M⊕

Mass (Jupiter)

0.837 M♃

Density

0.63 g/cm³

Surface Gravity

1.39 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.071

HZ Position Inner

Controversial No

Discovery

Year 2015

Method Transit

Facility HATSouth

Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#507of 1771

top 28.6%

This planet

13.85R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Kepler-731 b 13.88 R⊕ HATS-68 b 13.81 R⊕ WASP-25 b 13.81 R⊕

Metric	Earth	HATS-9 b	Jupiter
Radius (R⊕)	1.00	13.85	11.21
Mass (M⊕)	1.00	266.02	317.83
Density (g/cm³)	5.51	0.63	1.33
Surface Gravity (g)	1.00	1.39	2.53
Insolation (S⊕)	1.00	2,292.08	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	266.024 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 12611594

Gaia DR2

Gaia DR2 4083159643769233408

Gaia DR3

Gaia DR3 4083159643769233408

System

HATS-9

Percentile among Gas Giant cohort

Radius 13.850 R⊕ · percentile 71 / cohort 1771

Mass 266.024 M⊕ · percentile 29 / cohort 1747

Orbital period 1.92 d · percentile 6 / cohort 1533

Distance 638.70 pc · percentile 79 / cohort 1759

ESI 0.071 · percentile 13 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

1.915 days

Semi-major axis

0.0312 AU

Eccentricity

0.075

Inclination

88.94 °

Year Length

A year here lasts approximately 1.92 Earth days (0.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0312 AU.

Transit Fingerprint

Depth

0.847 %

Duration

3.508 h

Impact parameter b

0.160

Rp / R★

0.081400

Transit midpoint (BJD)

2,457,311.7514

Photometric dip

Transit produces a flux drop of 8,470 ppm lasting ≈ 3.51 h.

Extended Orbital Architecture

Planet / star radius ratio

0.081400

Semi-major axis / stellar radius

4.440

Impact parameter (b)

0.160

RV semi-amplitude (K)

133.500 m/s

Transit mid-time (BJD)

2,457,311.7514

Angular separation (arcsec)

0.04880

Eq. Temperature

1,746K

(1473 °C)

Insolation (S⊕)

2,292.08

Earth = 1.00

Earth Similarity (ESI)

0.071

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Brahm et al. 2015

Instrument

Apogee 4K CCD Sensor

Publication

2015-07

Observation locale

Ground

Discovery cohort

Planets confirmed in 2015 at HATSouth (6 shown).

HATS-6 b · Gas Giant HATS-7 b · Neptune-like HATS-14 b · Gas Giant HATS-10 b · Gas Giant HATS-13 b · Gas Giant HATS-8 b · Neptune-like

Host System: HATS-9

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,599 K — cooler than the Sun (5,778 K)

Estimated Age

10.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.560 R☉

Stellar Mass

1.100 M☉

Metallicity [Fe/H]

0.38

Extended Stellar Properties

Surface gravity (log g)

4.100 dex

Stellar density

0.451 g/cm³

Systemic radial velocity

-10.64 km/s

Rotational v·sin i

4.58 km/s

Metallicity ratio

[Fe/H]

Distance

638.70 parsec

Light-years 2,083.16 ly

V-band magnitude

13.26 mag

Voyager-speed travel 36,736,496 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Parallax

1.538 mas

Total Proper Motion

11.058 mas/yr

PM Right Ascension

8.57 mas/yr

PM Declination

-6.99 mas/yr

Galactic Cartesian (pc)

x = 0.333 · y = -0.877 · z = -0.345

Equatorial (J2000)

RA 290.81017° · Dec -20.16638°

Galactic ℓ, b

18.018° · -15.828°

Ecliptic λ, β

289.488° · 1.876°

HTM-20 index

-355968132