Key parameters at a glance

A radius of 1.80 Earth radii
A mass of 3.90 Earth masses
Surface gravity around 1.20 g
An orbital period of 98.211 days
Semi-major axis 0.4600 AU
Distance from Earth 1,956.94 light-years
Earth Similarity Index 0.824
Travel time at Voyager 1 speed 34,510,564 years

Context from the literature

PSR B1257+12 C, alternatively designated PSR B1257+12 d and also named Phobetor, is a super-Earth exoplanet orbiting the pulsar Lich approximately 2,315 light-years away from Earth in the constellation of Virgo. It was one of the first planets ever discovered outside the Solar System. It was discovered using the pulsar timing method, where the regular pulses of a pulsar are measured to determine if there is a planet causing variations in the data.

Excerpted from Wikipedia · full article

2 siblings around PSR B1257+12

PSR B1257+12 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
PSR B1257+12 b	Rocky Terrestrial	0.34	0.02	25.262	—	1994
PSR B1257+12 c	Super-Earth	1.91	4.30	66.542	—	1992
PSR B1257+12 d this	Super-Earth	1.80	3.90	98.211	—	1992

PSR B1257+12 d Planet Profile

Physical Specs

Radius

1.80 R⊕

Radius (Jupiter)

0.161 R♃

Mass

3.90 M⊕

Mass (Jupiter)

0.012 M♃

Density

3.67 g/cm³

Surface Gravity

1.20 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.824

HZ Position Unknown

Controversial No

Discovery

Year 1992

Method Pulsar Timing

Facility Arecibo Observatory

Telescope 305 m Arecibo Radio Telescope

Size rank in cohort

Rank by radius

#253of 1176

top 21.4%

This planet

1.80R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-11 b 1.80 R⊕ Kepler-148 b 1.80 R⊕ Kepler-296 f 1.80 R⊕

Metric	Earth	PSR B1257+12 d	Jupiter
Radius (R⊕)	1.00	1.80	11.21
Mass (M⊕)	1.00	3.90	317.83
Density (g/cm³)	5.51	3.67	1.33
Surface Gravity (g)	1.00	1.20	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	3.900 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	2.800 M⊕	Lower bound from radial-velocity fitting.

Percentile among Super-Earth cohort

Radius 1.800 R⊕ · percentile 77 / cohort 1176

Mass 3.900 M⊕ · percentile 71 / cohort 1176

Orbital period 98.21 d · percentile 98 / cohort 1164

Distance 600.00 pc · percentile 54 / cohort 1171

ESI 0.824 · percentile 91 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

98.211 days

Semi-major axis

0.4600 AU

Eccentricity

0.026

Inclination

47.00 °

Year Length

A year here lasts approximately 98.21 Earth days (26.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.4600 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.824

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Wolszczan et al. 1992

Instrument

Arecibo Radio Reciever

Publication

1992-01

Observation locale

Ground

Host System: PSR B1257+12

Spectral Class

Unknown

Effective Temperature

—

Estimated Age

3.00 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

—

Stellar Mass

1.400 M☉

Metallicity [Fe/H]

—

Distance

600.00 parsec

Light-years 1,956.94 ly

V-band magnitude

— mag

Voyager-speed travel 34,510,564 yr

Wikipedia → Image: Wikimedia Commons · Tyrogthekreeper (talk) · CC BY-SA 3.0

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