The V342 Peg system

V342 Peg is an F0+VkA5mA5 yellow-white star in Pegasus, 128.5 ly away, with 4 known planets. Their orbits run from 16 to 68 AU. All of them were detected by imaging.

HR 8799 dHR 8799 cHR 8799 bHR 8799 e · SOMEWHERE ON THIS ORBIT20 AU
28 AUG 2026 00:04 UTC
ACROSS
Seen from above the orbital plane, on a linear scale — the star is at a focus of every ellipse rather than in the middle of it, and on any other radial scale these would stop being ellipses. This is not the view from Earth: from here the system is edge-on, which for most of them is how they were found. The planets turn anticlockwise. 3 of the 4 planets are at the position their published period and epoch give for the instant on the clock, to within the 8.3 minutes by which a barycentric date and a wall clock can differ. 2 have an eccentricity published only as a bound, which is not a shape. One has a measured eccentricity and no published argument of periastron, so the shape is known and the direction it points is not. That is also the angle a position would be measured from, so those orbits are drawn as circles and carry no planet. The green band is where a planet would receive between 0.53 and 1.1 times the sunlight Earth does. It is a distance, not a verdict.
HR 8799 e16HR 8799 d24HR 8799 c38HR 8799 b68V342 PEG
Distances are semi-major axes in astronomical units on a linear axis. Planet discs are on their own scale, by cube root of radius, because at the orbital scale every one of them is smaller than a pixel.
[

THE PLANETS

] 4, INNERMOST FIRST
PLANET
ORBIT (AU)
PERIOD
RADIUS
MASS
EQUILIBRIUM T
HR 8799 e
16
56.99 yr
13.11 R⊕
3180 M⊕
1150 K
HR 8799 d
24
101.3 yr
13.00 R⊕
3000 M⊕
1300 K
HR 8799 c
38
188.9 yr
13.00 R⊕
3000 M⊕
1200 K
HR 8799 b
68
465.4 yr
13.00 R⊕
2000 M⊕
1200 K
[

WHAT THIS PAGE IS

] AND IS NOT

Every figure here is the NASA Exoplanet Archive’s composite parameter for that planet — one consistent set per world, not the best number for each column from a different paper. Semi-major axes are orbits about the star, not distances from Earth; the system as a whole is 128.5 ly away.

The band on the diagram is a distance and not a verdict. It is where a planet would receive between 0.53 and 1.1 times the sunlight Earth does, from a luminosity of 5.54 L☉. It says nothing about whether anything in it has an atmosphere, water, a magnetic field or a stable star.

Discovery order and orbital order are different things. Planets are lettered b, c, d in the order they were found, and this table is ordered by semi-major axis instead — which is why the letters on many of these pages are out of sequence.

The plan view at the top puts the planets where their published elements say they are, and there is one thing it deliberately cannot show: which way the whole system is tilted. The inclinations the archive publishes are measured against the plane of the sky, one per planet, and there is no longitude of the ascending node for any planet in this catalogue — so the view perpendicular to the orbits is the only one that needs nothing invented. What that costs is the view from Earth, which for most of these systems is very nearly edge-on, because a system seen any other way does not transit and would never have been found.