Hatysa
Iota Orionis
Scientific overview
Hatysa is a blue giant in the constellation Orion (Orionis), lying about 2,329.7 light-years from Earth.
Class O. Extremely hot, luminous blue stars. They are massive, short-lived, and rare, pouring out ultraviolet light. Such stars have surface temperatures around ≥ 30,000 K and appear blue to the eye.
Physical properties
| Spectral type | O9III |
| Luminosity class | III |
| Apparent magnitude | 2.75 |
| Absolute magnitude | -6.52 |
| Luminosity (Sun = 1) | 35,286 |
| Colour index (B−V) | -0.21 |
| Distance | 2,329.7 ly (714.29 pc) |
Values are real catalogue data; fields without a reliable value are omitted, never estimated.
Precision measurements
Astrometry and astrophysics from SIMBAD
| Parallax | 1.9969 ± 0.7299 mas | SIMBAD · measured |
| Proper motion (RA) | -2.816 mas/yr | SIMBAD · measured |
| Proper motion (Dec) | -1.693 mas/yr | SIMBAD · measured |
| Radial velocity | 27.6 ± 0.3 km/s | SIMBAD · measured |
| Spectral type | O9IIIvar | SIMBAD · catalogued |
| Right ascension (ICRS) | 83.8583 deg | SIMBAD · measured |
| Declination (ICRS) | -5.9099 deg | SIMBAD · 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
- 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 · 1970ApJS...19..387A · direct catalogue measurement · retrieved 2026-07-11
- Spectral type: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · sp_type · 2011ApJS..193...24S · 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 blue giant is a hot, massive, highly luminous star that has evolved off the main sequence. Such stars are short-lived on cosmic timescales.
Location in the sky
Knowledge connections
- In constellationOrion
Related stars in Orion
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.