---
license: cc-by-4.0
pretty_name: "Pluto Atmospheric Profiles (New Horizons)"
language:
  - en
description: "Pluto atmospheric profiles from the New Horizons flyby (July 2015). Temperature, pressure, composition (N2, CH4, C2H2), and haze from REX and Alice."
task_categories:
  - tabular-regression
tags:
  - space
  - pluto
  - atmosphere
  - new-horizons
  - planetary-science
  - nasa
  - pds
  - open-data
  - tabular-data
  - parquet
size_categories:
  - n<1K
configs:
  - config_name: rex_profiles
    data_files:
      - split: train
        path: data/rex_profiles.parquet
    default: true
  - config_name: alice_composition
    data_files:
      - split: train
        path: data/alice_composition.parquet
    default: false
  - config_name: haze_profiles
    data_files:
      - split: train
        path: data/haze_profiles.parquet
    default: false
---

# Pluto Atmospheric Profiles (New Horizons)

<div align="center">
  <img src="banner.jpg" alt="Saturn and its rings, captured by the Cassini spacecraft" width="400">
  <p><em>Credit: NASA/JPL-Caltech/SSI</em></p>
</div>

*Part of the [Solar System Datasets](https://huggingface.co/collections/juliensimon/solar-system-datasets-69c6fa681978de62dff2f347) collection on Hugging Face.*

The only direct measurements of **Pluto's atmosphere**, obtained during NASA's New Horizons flyby on July 14, 2015. This dataset includes vertical profiles of temperature, pressure, and number density from the REX radio occultation experiment, atmospheric composition (N2, CH4, C2H2, C2H4, C2H6, haze) from the Alice UV spectrometer, and haze brightness profiles from imaging.

## Dataset description

When New Horizons flew past Pluto at 13.78 km/s, it performed two critical atmospheric experiments. The **REX** (Radio Science Experiment) instrument used radio occultation — measuring how the spacecraft's radio signal was refracted by Pluto's atmosphere — to derive temperature and pressure as a function of altitude. This produced entry and exit profiles covering the lower atmosphere from the surface (~1,190 km radius) to ~115 km altitude.

The **Alice** ultraviolet spectrometer observed solar and stellar occultations through Pluto's atmosphere, measuring the absorption signatures of nitrogen (N2), methane (CH4), acetylene (C2H2), ethylene (C2H4), ethane (C2H6), and photochemical haze. These observations revealed a complex atmospheric chemistry driven by UV photolysis of methane, producing hydrocarbon species that condense into the extensive haze layers visible in New Horizons' departure images.

Pluto's atmosphere is tenuous (surface pressure ~1 Pa, vs. Earth's 101,325 Pa) and primarily composed of nitrogen, with trace methane and carbon monoxide. It undergoes dramatic seasonal changes as Pluto's eccentric orbit (perihelion 29.7 AU, aphelion 49.3 AU) causes surface ices to sublime and refreeze over its 248-year orbital period.

## Data tables

| Config | Rows | Description |
|--------|-----:|-------------|
| `rex_profiles` | 55 | Temperature, pressure, and number density vs. altitude (entry + exit occultations) |
| `alice_composition` | 1785 | Atmospheric mixing ratios and number densities of N2, CH4, C2H2, C2H4, C2H6, haze |
| `haze_profiles` | 29 | Azimuthally averaged haze I/F brightness vs. altitude |

## Quick stats (REX)

- Altitude range: 1 -- 115 km above surface
- Temperature range: 39 -- 107 K
- Two profiles: entry (ingress) and exit (egress) occultation

## Usage

```python
from datasets import load_dataset

# Load REX temperature/pressure profiles
rex = load_dataset("juliensimon/pluto-atmosphere", "rex_profiles", split="train")
df = rex.to_pandas()

# Plot Pluto's atmospheric temperature profile
import matplotlib.pyplot as plt
entry = df[df["profile"] == "rex_entry"]
exit_ = df[df["profile"] == "rex_exit"]
plt.plot(entry["temperature_k"], entry["altitude_km"], label="Entry")
plt.plot(exit_["temperature_k"], exit_["altitude_km"], label="Exit")
plt.xlabel("Temperature (K)")
plt.ylabel("Altitude (km)")
plt.title("Pluto Atmospheric Temperature Profile (New Horizons REX)")
plt.legend()
plt.show()

# Load composition data
alice = load_dataset("juliensimon/pluto-atmosphere", "alice_composition", split="train")
```

## Data source

New Horizons Derived Pluto System Atmospherics, PDS Small Bodies Node:
[doi:10.26007/z5wm-yt67](https://doi.org/10.26007/z5wm-yt67)

- Hinson et al. (2017), *Radio occultation measurements of Pluto's neutral atmosphere with New Horizons*, Icarus 290. [doi:10.1016/j.icarus.2017.02.031](https://doi.org/10.1016/j.icarus.2017.02.031)
- Young et al. (2018), *Structure and composition of Pluto's atmosphere from the New Horizons solar ultraviolet occultation*, Icarus 300. [doi:10.1016/j.icarus.2017.09.006](https://doi.org/10.1016/j.icarus.2017.09.006)

## Related datasets

- [Huygens Titan Atmosphere](https://huggingface.co/datasets/juliensimon/huygens-titan-atmosphere) — Titan atmospheric profiles (Cassini-Huygens)
- [Galileo Jupiter Atmosphere](https://huggingface.co/datasets/juliensimon/galileo-jupiter-atmosphere) — Jupiter atmospheric profiles (Galileo probe)
- [Solar System Moons](https://huggingface.co/datasets/juliensimon/solar-system-moons) — Physical properties of all known moons

## Pipeline

Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)

## Support

If you find this dataset useful, please give it a ❤️ on the [dataset page](https://huggingface.co/datasets/juliensimon/pluto-atmosphere) and share feedback in the Community tab! Also consider giving a ⭐ to the [space-datasets](https://github.com/juliensimon/space-datasets) repo.

## Citation

```bibtex
@dataset{pluto_atmosphere,
  author = {Simon, Julien},
  title = {Pluto Atmospheric Profiles (New Horizons)},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/pluto-atmosphere},
  note = {Based on New Horizons derived data, PDS Small Bodies Node}
}
```

## License

[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)