NN Ser d
The parameters of this planet are disputed or ambiguous in the scientific literature.
NN Ser d is a cold gas giant orbiting the WD star NN Ser in the constellation Serpens. It lies about 1,682 light-years from Earth and was discovered in 2010 using the eclipse timing variations method.
Is NN Ser d in the Habitable Zone?
The position of NN Ser d relative to the habitable zone of NN Ser cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on NN Ser d — one full orbit around NN Ser — lasts 2,880.0 Earth days, longer than an Earth year. Its orbit is mildly elliptical (eccentricity 0.24).
How Was NN Ser d Discovered?
NN Ser d was discovered in 2010 using the eclipse timing variations method, with observations from Multiple Observatories.
Eclipse timing variations detect a planet orbiting an eclipsing pair of stars: the planet's gravity shifts the precise moments when the stars eclipse each other.
How Far Away Is NN Ser d?
NN Ser d is 1,682.4 light-years (515.8 parsecs) from Earth. Light arriving here tonight left the planet about 1,682 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 29,610,240 years to make the journey.
The Host Star: NN Ser
NN Ser d is a circumbinary planet — it orbits around two stars at once, like Tatooine in Star Wars.
NN Ser
- Spectral type
- WD
- Mass
- 0.54 M☉
The NN Ser Planetary System
NN Ser d is one of 2 known planets in the NN Ser system. Its siblings:
- NN Ser c (Cold Gas Giant)
NN Ser d — Complete Data
| Mass (best estimate) | 696.04 Earth masses |
|---|---|
| Orbital period | 2,880.00 days |
| Eccentricity | 0.240 |
| Distance from Earth | 1,682.4 light-years (515.8 parsecs) |
| Constellation | Serpens |
| Discovery method | Eclipse Timing Variations |
| Discovery facility | Multiple Observatories |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2025-12-18. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About NN Ser d
Is NN Ser d habitable?
NN Ser d is not known to orbit within the habitable zone of NN Ser, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is NN Ser d?
NN Ser d is about 1,682 light-years from Earth in the constellation Serpens. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 29,610,240 years to get there.
How long is a year on NN Ser d?
One orbit around NN Ser takes 2,880.0 Earth days.
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