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Star · Hercules

101 Herculis

Knowledge graph101 HerHR 6794HD 166230HIP 88899

Scientific overview

101 Herculis is a star in the constellation Hercules (Herculis), lying about 328.8 light-years from Earth.

Class A. White stars with strong hydrogen lines. Many of the brightest stars in the sky are class A. Such stars have surface temperatures around 7,500–10,000 K and appear white to the eye.

Physical properties

Spectral typeA8III
Luminosity classIII
Apparent magnitude5.1
Absolute magnitude0.08
Luminosity (Sun = 1)80.686
Colour index (B−V)0.176
Distance328.8 ly (100.81 pc)

Values are real catalogue data; fields without a reliable value are omitted, never estimated.

Precision measurements

Astrometry and astrophysics from SIMBAD and Gaia DR3 · Gaia DR3 4527896021146097408

Parallax9.5493 ± 0.0851 masSIMBAD · measured
Distance104.4 pcGaia · estimated
Proper motion (RA)9.056 mas/yrSIMBAD · measured
Proper motion (Dec)-20.83 mas/yrSIMBAD · measured
Radial velocity-16.3 ± 0.9 km/sSIMBAD · measured
Spectral typeA8IIISIMBAD · catalogued
Effective temperature8580.6 KGaia · modeled
Radius4.8949 R_sunGaia · modeled
Surface gravity (log g)3.4911 log(cm/s^2)Gaia · modeled
Metallicity [M/H]0.0889 dexGaia · modeled
Right ascension (ICRS)272.2 degSIMBAD · measured
Declination (ICRS)20.0452 degSIMBAD · measured
Full field-level provenance
  • Parallax: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · plx_value · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
  • Distance: ESA Gaia astrometric survey · Gaia EDR3 · Bailer-Jones (2021) · external.gaiaedr3_distance · r_med_geo · row 4527896021146097408 · Bayesian estimate · retrieved 2026-07-11
  • Proper motion (RA): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · pmra · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
  • Proper motion (Dec): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · pmdec · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
  • Radial velocity: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · rvz_radvel · 1979IAUS...30...57E · direct catalogue measurement · retrieved 2026-07-11
  • Spectral type: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · sp_type · catalogue identifier/value · retrieved 2026-07-11
  • Effective temperature: ESA Gaia astrometric survey · Gaia DR3 · gaiadr3.astrophysical_parameters · teff_gspphot · row 4527896021146097408 · model output · retrieved 2026-07-11
  • Radius: ESA Gaia astrometric survey · Gaia DR3 · gaiadr3.astrophysical_parameters · radius_gspphot · row 4527896021146097408 · model output · retrieved 2026-07-11
  • Surface gravity (log g): ESA Gaia astrometric survey · Gaia DR3 · gaiadr3.astrophysical_parameters · logg_gspphot · row 4527896021146097408 · model output · retrieved 2026-07-11
  • Metallicity [M/H]: ESA Gaia astrometric survey · Gaia DR3 · gaiadr3.astrophysical_parameters · mh_gspphot · row 4527896021146097408 · model output · retrieved 2026-07-11
  • Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
  • Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11

measured = direct catalogue value · estimated = Bayesian inference (Bailer-Jones distance) · modeled = model output (Gaia GSP-Phot). Fields a source did not provide are omitted, never invented.

Location in the sky

Constellation
Hercules
Hemisphere
Northern
Best seen
Summer (N. evening sky)
RA / Dec
18.148h / 20.0452°

Knowledge connections

  • In constellationHercules

Sources

The primary and reference sources this topic draws on.

  • HYG DatabaseHYG Database (Hipparcos + Yale Bright Star + Gliese), by D. Nash / astronexus

    Aggregated, openly-licensed star catalogue combining Hipparcos, the Yale Bright Star Catalogue, and the Gliese Catalogue of Nearby Stars.

  • HipparcosESA Hipparcos space astrometry mission

    High-precision parallax, magnitude, and position for ~118,000 stars.