Epsilon Sagittae (ε Sge) is a star designated with the Bayer letter ε in the constellation Sagitta. It appears in several major astronomical catalogs, including the Henry Draper Catalogue (HD 184606) and the Hipparcos catalogue (HIP 96230).
Observational characteristics
- Apparent magnitude: Approximately 5.6 mag, rendering the star faintly visible to the naked eye under good dark‑sky conditions.
- Spectral type: Classified as a K‑type giant (commonly reported as K2 III), indicating an evolved, orange–hued star that has left the main sequence.
- Color index: The B–V color index is around +1.0, consistent with its cool temperature relative to the Sun.
Physical properties
- Luminosity: As a giant star, ε Sge radiates several tens of times the Sun’s luminosity.
- Radius: Its radius is larger than the Sun’s, typical for K‑type giants.
- Distance: Parallax measurements from the Hipparcos mission place the star at a distance of roughly 150–200 parsecs (≈ 500–650 light‑years), though exact values depend on the adopted reduction of the data.
Kinematic data
- Proper motion: ε Sge exhibits a modest proper motion across the sky, measurable in milliarcseconds per year.
- Radial velocity: Spectroscopic observations give a small radial velocity relative to the Solar System, indicating a modest motion toward or away from the Sun.
Catalog identifiers
- Bayer designation: ε Sagittae
- Flamsteed designation: 13 Sagittae (occasionally used)
- Henry Draper Catalogue: HD 184606
- Hipparcos catalogue: HIP 96230
- Bright Star Catalogue: HR 7345
Location
Epsilon Sagittae lies near the northern edge of the narrow constellation Sagitta, the Arrow. Its celestial coordinates (J2000) are approximately Right Ascension 19ʰ 40ᵐ 22ˢ and Declination +18° 38′ 00″.
Notes
The star is not known to possess any confirmed stellar companions, planetary system, or unusual variability. It is primarily of interest as a typical K‑type giant used in studies of stellar evolution and as a reference point for amateur observations of the Sagitta region.