Star · G2V main-sequence star (yellow dwarf)

The Sun

Type: G2V main-sequence star (yellow dwarf)
Diameter: 1,391,400 km
Mean temp.: 5505 °C

NASA/GSFC/Solar Dynamics Observatory · NASA media (public domain)

Overview

Scientific overview

The Sun is a g2v main-sequence star (yellow dwarf).

Physical characteristics

Mass: 1,989,000 ×10²⁴ kg
Diameter: 1,391,400 km
Radius: 696,340 km
Surface gravity: 273.77 m/s² · derived
Escape velocity: 617.5 km/s · derived
Mean temperature: 5505 °C

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

Escape velocity617.5 km/sderived
Formula & inputs
Formula: v = √(2GM / r) (v1.0.0, impl v1.0.0)
Inputs:
- mass1e24Kg = 1989000 ×10²⁴ kg · NASA
- radiusKm = 696340 km · NASA
Assumptions: G = 6.674e-11 m³ kg⁻¹ s⁻² (CODATA 2018)
Limitations: Assumes a spherical, non-rotating body.; Inputs carry no catalogued uncertainty, so none is propagated.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.
Surface gravity273.77 m/s²derived
Formula & inputs
Formula: g = GM / r² (v1.0.0, impl v1.0.0)
Inputs:
- mass1e24Kg = 1989000 ×10²⁴ kg · NASA
- radiusKm = 696340 km · NASA
Assumptions: G = 6.674e-11 m³ kg⁻¹ s⁻² (CODATA 2018)
Limitations: Assumes a spherical, non-rotating body.; Inputs carry no catalogued uncertainty, so none is propagated.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.

Scale

Compared to Earth

Earth

The Sun

The Sun is 109× Earth

1,391,400 km across · Earth is 12,742 km

Gallery

Image of Sun From NASA's Solar Dynamics Observatory
On Sept. 10, 2025, NASA's Solar Dynamics Observatory captured this image of the Sun. SDO is managed by NASA's Goddard Space Flight Center, Greenbelt, Maryland, for NASA's Science Mission Directorate in Washington. Its A…
2025
NASA/GSFC/Solar Dynamics Observatory · NASA media (public domain)
Source archive ↗

Observation

How this was captured

Observatory / instrument: Atmospheric Imaging Assembly
Mission: Solar Dynamics Observatory
Source: NASA
Observation date: 2025-09-10

Exploration

Sources

The primary and reference sources this topic draws on.

NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.

Quick facts

Type: G2V main-sequence star (yellow dwarf)

Provenance & sources

review 2026.1

Asteria Scientific Review Process · verification: sourced · accurate

High evidenceconfirmed
The Sun is a G-type main-sequence star (G2V) at the centre of the Solar System, containing about 99.86% of the system's mass; sunlight takes roughly 8.3 minutes to reach Earth.
Source: NASA (NSSDCA) — NASA Planetary Fact Sheet · Public domain (US Government work)
- NASA Planetary Fact Sheet, Planetary Fact Sheet

Reviewed by the internal Asteria Scientific Review Process — not an external institutional review. See the evidence framework and authority dashboard.

Scientific citations

Real, source-backed references — primary papers first, then datasets and institutional sources. Formatted through the citation engine; nothing is fabricated.

Institutional pageNOAA Solar Calculator

NOAA Global Monitoring Laboratory

Cite (APA / BibTeX)

NOAA Global Monitoring Laboratory (n.d.). NOAA Solar Calculator. NOAA Global Monitoring Laboratory. https://gml.noaa.gov/grad/solcalc/

@misc{cite:noaa-solar-calculator,
  title        = {NOAA Solar Calculator},
  organization = {NOAA Global Monitoring Laboratory},
  year         = {n.d.},
  url          = {https://gml.noaa.gov/grad/solcalc/},
  note         = {Public-domain solar-position algorithm — declination, equation of time, sunrise/sunset, and twilight — the method implemented by the computed Sun & Twilight times.}
}

Institutional pageSun — NASA Solar System Exploration

NASA

Cite (APA / BibTeX)

NASA (n.d.). Sun — NASA Solar System Exploration. NASA. https://science.nasa.gov/

@misc{cite:nasa-star-sun,
  title        = {Sun — NASA Solar System Exploration},
  organization = {NASA},
  year         = {n.d.},
  url          = {https://science.nasa.gov/},
  note         = {NASA overview of Sun.}
}

Institutional pageThe Sun — NASA Science

NASA

Cite (APA / BibTeX)

NASA (n.d.). The Sun — NASA Science. NASA. https://science.nasa.gov/sun/

@misc{cite:nasa-sun,
  title        = {The Sun — NASA Science},
  organization = {NASA},
  year         = {n.d.},
  url          = {https://science.nasa.gov/sun/},
  note         = {NASA overview of the Sun: our star, its structure, and its role in day, night, and the seasons.}
}

Institutional pageUSNO Astronomical Applications Department

United States Naval Observatory

Cite (APA / BibTeX)

United States Naval Observatory (n.d.). USNO Astronomical Applications Department. United States Naval Observatory. https://aa.usno.navy.mil/

@misc{cite:usno-astronomical-applications,
  title        = {USNO Astronomical Applications Department},
  organization = {United States Naval Observatory},
  year         = {n.d.},
  url          = {https://aa.usno.navy.mil/},
  note         = {Solar and lunar coordinates, phase, and rise/set/twilight/transit methodology (the Astronomical Almanac); the public-domain formulae behind the computed Moon phase, the computed Sun & twilight times, and the computed moonrise/moonset and lunar position.}
}

Quality & authority

Substantial

Reviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: Complete
Citation coverage: Complete
Image coverage: Complete

Data from the NASA Planetary Fact Sheet & JPL (public domain). See source quality.

The Sun

Scientific overview

Physical characteristics

Derived values

Compared to Earth

Gallery

How this was captured

Exploration

Parker Solar Probe

Solar Orbiter

Sources