Struve 2398
Template:Short description Template:Sky
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco[1][2] |
| Struve 2398 A | |
| Right ascension | Template:RA[3] |
| Declination | Template:DEC[3] |
| Apparent magnitude (V) | 8.94[4] |
| Struve 2398 B | |
| Right ascension | Template:RA[5] |
| Declination | Template:DEC[5] |
| Apparent magnitude (V) | 9.70[4] |
| Characteristics | |
| Spectral type | M3 V + M3.5 V[6] |
| U−B Template:Engvar | 1.11/1.14 |
| B−V Template:Engvar | 1.53/1.59 |
| Variable type | Flare star |
| Astrometry | |
| Struve 2398 A | |
| Radial velocity (Rv) | Script error: No such module "val".[3] km/s |
| Proper motion (μ) | RA: –1311.679 mas/yr[3] Dec.: +1792.325 mas/yr[3] |
| Parallax (π) | 283.8401±0.0220 mas[3] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | +11.18[1] |
| Struve 2398 B | |
| Radial velocity (Rv) | Script error: No such module "val".[5] km/s |
| Proper motion (μ) | RA: –1400.264 mas/yr[5] Dec.: +1862.525 mas/yr[5] |
| Parallax (π) | 283.8378±0.0287 mas[5] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | +12.01[2] |
| Orbit[7] | |
| Period (P) | Script error: No such module "val". years |
| Semi-major axis (a) | Script error: No such module "val".[8] |
| Eccentricity (e) | Script error: No such module "val". |
| Inclination (i) | Script error: No such module "val".° |
| Longitude of the node (Ω) | Script error: No such module "val".° |
| Periastron epoch (T) | Script error: No such module "val". |
| Argument of periastron (ω) (secondary) | Script error: No such module "val".° |
| Details[8] | |
| Struve 2398 A | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Luminosity | Script error: No such module "val". Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | Script error: No such module "val".[6] dex |
| Rotation | Script error: No such module "val".[9] days |
| Rotational velocity (v sin i) | < 2.5[10] km/s |
| Age | Script error: No such module "val". Gyr |
| Struve 2398 B | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Luminosity | 0.021 Template:Solar luminosity |
| Surface gravity (log g) | 4.41[5] cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | Script error: No such module "val".[6] dex |
| Rotation | Script error: No such module "val".[9] days |
| Rotational velocity (v sin i) | < 2.5[10] km/s |
| Age | 2.4[6] Gyr |
| Other designations | |
| Template:Odlist, GCTP 4330.00 A/B | |
| Struve 2398 A: Template:Odlist | |
| Struve 2398 B: Template:Odlist | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
| Exoplanet Archive | data |
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Struve 2398 (Gliese 725) is a binary star system in the northern constellation of Draco. Struve 2398 is star number 2398 in the Struve Double Star Catalog of Russian-German astronomer Friedrich Georg Wilhelm von Struve. The astronomer's surname, and hence the star identifier, is sometimes indicated by a Greek sigma, Σ; hence, this system can be listed with the identifier Σ 2398. Although the components are too faint to be viewed with the naked eye, this star system is among the closest to the Sun. Parallax measurements by the Gaia spacecraft give them an estimated distance of Script error: No such module "convert". away.
Both stars are small red dwarfs, with each having around a third the Sun's mass and radius. They each display the type of variability common to flare stars,[11] and their active surfaces are sources of X-ray emission.[12] They are orbiting with a period of about 871 years, at a separation of about 63 astronomical units with an orbital eccentricity of 0.29.[8]
The pair has a relatively high proper motion of 2.2 arc seconds per year. The system is on an orbit through the Milky Way that has an eccentricity of 0.05, carrying them as close as 8 kpc and as far as 9 kpc from the Galactic Center. The plane of their galactic orbit carries them as far as 463−489 pc away from the galactic plane.[13]
Planetary system
Struve 2398 A is known to host one planet, a likely super-Earth discovered in 2024 using the radial velocity method. This planet has a minimum mass 2.8 times that of Earth, and has a close orbit with a period of 11 days; it is too close to its star to be in the habitable zone. TESS observations show that the planet likely does not transit its host star.[8]
Struve 2398 B may also host planets. In 2016, an Earth-mass planet candidate on a 2.7-day orbit was proposed around Struve 2398 B based on radial velocity observations, although this could not be confirmed as a periodic signal.[14]
Template:OrbitboxPlanet begin Template:OrbitboxPlanet
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References
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