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AsteriaStar
Main-sequence star · Ara

Sigma Arae

Knowledge graphSigma Ara1 AraHR 6537HD 159217

Scientific overview

Sigma Arae is a main-sequence star in the constellation Ara (Arae), lying about 378.4 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 typeA0V
Luminosity classV
Apparent magnitude4.56
Absolute magnitude-0.76
Luminosity (Sun = 1)176
Colour index (B−V)-0.02
Distance378.4 ly (116.01 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 5949068676156098944

Parallax8.5285 ± 0.1394 masSIMBAD · measured
Distance116.8 pcGaia · estimated
Proper motion (RA)-25.046 mas/yrSIMBAD · measured
Proper motion (Dec)-39.43 mas/yrSIMBAD · measured
Radial velocity4.3 ± 2 km/sSIMBAD · measured
Spectral typeA0VSIMBAD · catalogued
Right ascension (ICRS)263.9 degSIMBAD · measured
Declination (ICRS)-46.5057 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 5949068676156098944 · 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 · 1953GCRV..C......0W · direct catalogue measurement · retrieved 2026-07-11
  • Spectral type: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · sp_type · 1978MSS...C02....0H · catalogue identifier/value · 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.

Evolution

A main-sequence star fuses hydrogen into helium in its core. It will remain on the main sequence for most of its life before evolving into a giant.

Location in the sky

Constellation
Ara
Hemisphere
Southern
Best seen
Summer (N. evening sky)
RA / Dec
17.5943h / -46.5057°

Knowledge connections

  • In constellationAra

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.