Confirmed Exoplanet Discovered 2020

HATS-48 A b

A neptune-like orbiting the k-type orange HATS-48 A, located approximately 859.8 light-years from Earth.

Key parameters at a glance

  • A radius of 8.97 Earth radii
  • A mass of 77.23 Earth masses
  • Surface gravity around 0.96 g
  • An orbital period of 3.132 days
  • Semi-major axis 0.0377 AU
  • Equilibrium temperature 955 K (681 °C)
  • Distance from Earth 859.78 light-years
  • Earth Similarity Index 0.156
  • Travel time at Voyager 1 speed 15,162,159 years
  • Almost certainly tidally locked to its host star given the close orbit

HATS-48 A b Planet Profile

Physical Specs

Radius
8.97 R⊕
Radius (Jupiter)
0.800 R♃
Mass
77.23 M⊕
Mass (Jupiter)
0.243 M♃
Density
0.59 g/cm³
Surface Gravity
0.96 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.156
HZ Position Inner
Controversial No

Discovery

Year 2020
Method Transit
Facility HATSouth
Telescope 0.18 m Takahashi Epsilon Astrograph

Size rank in cohort

Rank by radius

#93of 574

top 16.0%

This planet

8.97R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth HATS-48 A b Jupiter
Radius (R⊕)1.008.9711.21
Mass (M⊕)1.0077.23317.83
Density (g/cm³)5.510.591.33
Surface Gravity (g)1.000.962.53
Insolation (S⊕)1.00137.600.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 77.233 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 201642601

Gaia DR2

Gaia DR2 6638412919991750912

Gaia DR3

Gaia DR3 6638412919991750912

System

HATS-48

Percentile among Neptune-like cohort

Radius 8.967 R⊕ · percentile 84 / cohort 574
Mass 77.233 M⊕ · percentile 88 / cohort 574
Orbital period 3.13 d · percentile 4 / cohort 524
Distance 263.61 pc · percentile 45 / cohort 572
ESI 0.156 · percentile 16 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
3.132 days
Semi-major axis
0.0377 AU
Eccentricity
0.162
Inclination
89.58 °

Year Length

A year here lasts approximately 3.13 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0377 AU.

Transit Fingerprint

Depth

1.492 %

Duration

2.346 h

Impact parameter b

0.083

Rp / R★

0.114800

Transit midpoint (BJD)

2,457,100.5502

Photometric dip

Transit produces a flux drop of 14,916 ppm lasting ≈ 2.35 h.

Extended Orbital Architecture

Planet / star radius ratio

0.114800

Semi-major axis / stellar radius

11.330

Impact parameter (b)

0.083

RV semi-amplitude (K)

41.800 m/s

Transit mid-time (BJD)

2,457,100.5502

Angular separation (arcsec)

0.14300

Eq. Temperature

955K

(681 °C)

Insolation (S⊕)

137.60

Earth = 1.00

Earth Similarity (ESI)

0.156

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

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

Hartman et al. 2020

Instrument

Apogee 4K CCD Sensor

Publication

2020-04

Observation locale

Ground

Host System: HATS-48 A

Spectral Class

K-type orange

Effective Temperature

4,546 K — cooler than the Sun (5,778 K)

Estimated Age

11.97 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.715 R☉

Stellar Mass

0.728 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

4.591 dex

Stellar density

2.804 g/cm³

Systemic radial velocity

-22.46 km/s

Rotational v·sin i

0.73 km/s

Metallicity ratio

[Fe/H]

Distance
263.61 parsec
Light-years 859.78 ly
V-band magnitude
14.23 mag
Voyager-speed travel 15,162,159 yr

Multi-band Host Photometry — 14 bands

8.915.615.57B14.23V13.90Gaia13.17TESS14.94Sloan g13.82Sloan r13.69Sloan i12.16J11.59H11.43K11.36W111.46W211.35W38.94W4

Astrometric Data

Parallax

3.765 mas

Total Proper Motion

6.895 mas/yr

PM Right Ascension

3.12 mas/yr

PM Declination

6.15 mas/yr

Galactic Cartesian (pc)

x = 0.162 · y = -0.480 · z = -0.862

Equatorial (J2000)

RA 288.67200° · Dec -59.57935°

Galactic ℓ, b

337.030° · -26.030°

Ecliptic λ, β

281.691° · -36.896°

HTM-20 index

-1049856634

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