HR 8799 / STELLAR DOSSIER

HR 8799

134.68 light-years from Sol

A pale star surrounded by four directly imaged giant planets and dusty debris.

Stellar view ↗

01
Artist’s impression of HR 8799
A/F-type · planet host

A young system we can watch in motion.

Stellar conditions ↗

02
EFFECTIVE TEMPERATURE7,193 K

Light from the outer layers.

HR 87997,193 K
Sol5,770 K
Shared scale 0–10,000 K · effective, not core temperature

Evolution ↗

03
CURRENT PHASE

Main sequence.

  1. NOWMain sequence
  2. PROCESSChanging internal structure
  3. OUTLOOKModel-dependent evolution
A physical sequence, not a lifetime scale or a countdown.

Photosphere & activity ↗

05
Artist’s impression. The curved luminous layers and detailed gas texture are illustrative, not a measured surface map.Across the luminous edge ↗ ARTIST’S IMPRESSION · 3 VIEWS

Diameter comparison ↗

06
1.44 × Sol

Luminosity ↗

07
≈ 5.01 × Sol

Total energy emitted · all wavelengths

Estimated from size and temperature
Sources ↗
HR 8799

Instrument detail

Artist’s impression of HR 8799

Artist’s impression · structure and color are illustrative.

Four points beside their star.

The giant planets b, c and d were reported through direct imaging in 2008; the inner planet e followed in 2010. Their light can be separated from the host, enabling spectra and repeated position measurements.

Young planets glow for themselves.

The planets remain warm from formation and contraction. Infrared observations therefore detect their own thermal radiation, not merely reflected starlight. Brightness still requires atmospheric and evolutionary models to become a mass estimate.

A system beyond its planets.

Dust belts trace material outside and inside the giant-planet region. The scene shows an illustrative belt rather than the measured geometry. Dust emission helps reveal a system whose small bodies cannot be individually resolved.

STELLAR PROFILESIZE · TEMPERATURE · EVOLUTION

A star in perspective.

DIAMETER / SOL1.44 ×

About 44% wider than our Sun.

Circles compare diameter, not mass or luminosity. Radius 1.44 ± 0.06 solar radii from the Baines et al. (2012) interferometric solution. The map separately uses the archive’s newer parallax.

EFFECTIVE TEMPERATURE

Light from the outer layers.

  • HR 8799≈ 7,193 K
  • Sol≈ 5,770 K

Shared scale: 0–10,000 K. Effective temperature describes total emitted energy per unit surface area; it is not the core temperature. Effective temperature 7,193 ± 87 K from Baines et al. (2012).

LIFE PHASE

Main sequence.

  1. NOWMain sequence
  2. PROCESSChanging internal structure
  3. OUTLOOKModel-dependent evolution

A physical sequence, not a lifetime scale or a countdown.

Research · size and temperature ↗
LIFE & HUMAN SURVIVAL / THE STAR ITSELF
POSSIBILITY FOR LIFEIncompatible with known life

The star’s hot gaseous layers cannot provide the cool, stable environment required by life as we know it. Conditions on any orbiting worlds are a separate question.

WITHOUT PROTECTIONNot survivable

No breathable air or solid ground. Extreme heat and radiation make a close encounter lethal; a meaningful survival timer depends on where you are.

NASA · stellar structure and evolution ↗

Main sequence.

  1. NOWMain sequence
  2. PROCESSChanging internal structure
  3. OUTLOOKModel-dependent evolution

A physical sequence, not a lifetime scale or a countdown.

Research ↗

How much energy leaves the star?

≈ 5.01 × Sol

This compares total radiant power across all wavelengths, not just visible light or apparent brightness in our sky. The beams on the dashboard share a linear length scale.

The estimate combines this log’s diameter ratio (1.44 × Sol) and effective temperature (7,193 K): luminosity scales with radius squared and temperature to the fourth power. It is derived from rounded values, not an independent luminosity measurement.

Radius 1.44 ± 0.06 solar radii from the Baines et al. (2012) interferometric solution. The map separately uses the archive’s newer parallax.

Effective temperature 7,193 ± 87 K from Baines et al. (2012).

Swinburne University · Stefan–Boltzmann law ↗

Four points beside their star.

The giant planets b, c and d were reported through direct imaging in 2008; the inner planet e followed in 2010. Their light can be separated from the host, enabling spectra and repeated position measurements.

Young planets glow for themselves.

The planets remain warm from formation and contraction. Infrared observations therefore detect their own thermal radiation, not merely reflected starlight. Brightness still requires atmospheric and evolutionary models to become a mass estimate.

A system beyond its planets.

Dust belts trace material outside and inside the giant-planet region. The scene shows an illustrative belt rather than the measured geometry. Dust emission helps reveal a system whose small bodies cannot be individually resolved.

Artist’s impression. The curved luminous layers and detailed gas texture are illustrative, not a measured surface map.

Across the luminous edge

Artist’s impression. The curved luminous layers and detailed gas texture are illustrative, not a measured surface map.

Artist’s impression of the host and a debris belt. Belt geometry, brightness and stellar scale are illustrative; the planets are not shown.

A dusty planetary system

Artist’s impression of the host and a debris belt. Belt geometry, brightness and stellar scale are illustrative; the planets are not shown.

Artist’s impression. The expanded field places the object in an imagined setting. Exposure and apparent scale are adjusted for clarity.

A wider view

Artist’s impression. The expanded field places the object in an imagined setting. Exposure and apparent scale are adjusted for clarity.

Stellar images are artistic interpretations, not resolved photographs of this star.