Ross 154

Star

Ross 154 — a red dwarf (M3.5V) 9.7 light-years away in Sagittarius, and one of the more active flare stars near the Sun: it brightens sharply several times a day as magnetic energy is released. About 17% of the Sun's mass. No planets are confirmed.

Open in 3D viewSee Ross 154 in the live, interactive 3D map

Key facts

Mass

3.38 × 10²⁹ kg

0.17 M☉

Radius

166,968 km

24% of the Sun's radius

Surface temperature

3,248 K (2,975 °C)

Luminosity

1.45 × 10²⁴ W

Spectral type

M3.5V (red dwarf; variable V1216 Sagittarii)

Science

Physical

Mass: 3.38 × 10²⁹ kg · 0.17 M☉
Radius: 166,968 km · 24% of the Sun's radius
Density: 17,341 kg/m³ · 17× water; Computed from mass and radius
Spectral type: M3.5V (red dwarf; variable V1216 Sagittarii)

Motion through space

Proper motion: 0.668 arcseconds per year · its drift across our sky; SIMBAD — 2020yCat.1350....0G, 2018A&A...616A...7S
Radial velocity: -10.5 km/s · approaching the Sun; SIMBAD — 2020yCat.1350....0G, 2018A&A...616A...7S
Speed across our line of sight: 9.43 km/s; Computed from proper motion and parallax
Speed through space, relative to the Sun: 14.1 km/s; Computed from proper motion, parallax and radial velocity

Composition

By mass: A red dwarf about 17% of the Sun's mass, comparatively young and magnetically very active — it flares several times a day, releasing bursts of ultraviolet and X-ray light.

Temperature

Surface: 3,248 K (2,975 °C)

Radiation & temperature

Luminosity: 1.45 × 10²⁴ W · 0.0038 L☉
Surface temperature: 3,248 K (2,975 °C)
Peak wavelength: 892 nm · near-infrared (mostly invisible to the eye); Computed (Wien's law) from the surface temperature

Discovery & history

Discovered: 1925
By: Frank Elmore Ross
Method: Telescope
Name: Named for the American astronomer Frank Elmore Ross and its number in his list; its variable-star name is V1216 Sagittarii.

Catalogued by Frank Elmore Ross in 1925 from his proper-motion survey (entry 154). Its frequent flaring earned it the variable-star name V1216 Sagittarii. No planet has been confirmed around it.

Images

Where to find it — in Sagittarius, the Archer (IAU constellation chart). It is an unresolved point of light; its surface has never been imaged. — IAU / Sky & Telescope, R. Sinnott & R. Fienberg (CC BY 3.0) · Wikimedia Commons

Images from open archives · credit shown per image