Ross 687
Scientific overview
Ross 687 is a red dwarf in the constellation Hydra (Hydrae), lying about 68.3 light-years from Earth.
Class M. Cool red stars. The most common type in the galaxy, ranging from red dwarfs to red giants. Such stars have surface temperatures around 2,400–3,700 K and appear red to the eye.
Physical properties
| Spectral type | M4 |
| Apparent magnitude | 12.37 |
| Absolute magnitude | 10.77 |
| Luminosity (Sun = 1) | 0.004 |
| Colour index (B−V) | 1.455 |
| Distance | 68.3 ly (20.94 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 583257319006770176 · elevated RUWE
| Parallax | 45.1497 ± 0.0375 mas | SIMBAD · measured |
| Distance | 22.138 pc | Gaia · estimated |
| Proper motion (RA) | -255.4 mas/yr | SIMBAD · measured |
| Proper motion (Dec) | -207.2 mas/yr | SIMBAD · measured |
| Radial velocity | -37.0223 ± 4.394e-3 km/s | SIMBAD · measured |
| Spectral type | M3.0V | SIMBAD · catalogued |
| Right ascension (ICRS) | 135.2 deg | SIMBAD · measured |
| Declination (ICRS) | 5.2415 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
- Distance: ESA Gaia astrometric survey · Gaia EDR3 · Bailer-Jones (2021) · external.gaiaedr3_distance · r_med_geo · row 583257319006770176 · 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 · 2020AJ....160..120J · direct catalogue measurement · retrieved 2026-07-11
- Spectral type: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · sp_type · 2013AJ....145..102L · 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 red dwarf is a small, cool, low-mass main-sequence star. Red dwarfs burn their fuel so slowly that they can shine for tens of billions of years — far longer than the present age of the universe.
Location in the sky
Knowledge connections
- In constellationHydra
- System includesRoss 686
Related stars in Hydra
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.