Struve 2398

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Struve 2398 A/B
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 18h 42m 46.7/46.9s
Declination +59° 37′ 49/36″
Apparent magnitude (V) 8.94[1]/9.70
Characteristics
Spectral type M3 V/M3.5 V
U−B color index 1.11/1.14
B−V color index 1.53/1.59
Variable type Flare star
Astrometry
Radial velocity (Rv) –0.9 km/s
Proper motion (μ) RA: –1327 mas/yr
Dec.: +1802 mas/yr
Parallax (π) 283.00 ± 1.69 mas
Distance 11.52 ± 0.07 ly
(3.53 ± 0.02 pc)
Absolute magnitude (MV) 11.20/11.96
Details
Struve 2398 A
Mass 0.36 M
Radius 0.55 R
Luminosity 0.039 L
Temperature 3,680 ± 18[1] K
Metallicity [Fe/H] -0.49 ± 0.17[1] dex
Struve 2398 B
Mass 0.30 M
Radius 0.54 R
Luminosity 0.021 L
Temperature 3,000 K
Orbit[2]
Companion Struve 2398 B
Period (P) 294.7 yr
Semi-major axis (a) 10.50"
Eccentricity (e) 0.70
Inclination (i) 52.5°
Longitude of the node (Ω) 139.9°
Periastron epoch (T) 1778.0
Argument of periastron (ω)
(secondary)
203.8°
Database references
SIMBAD data
Other designations
Gl 725 A/B, ADS 11632, HD 173739/173740, GCTP 4330.00 A/B, LHS 58/59, G 227-046/227-047, HIP 91768/91772, A: BD +59°1915, Vyssotsky 184.
Database references
SIMBAD data

Struve 2398 (Gliese 725[3]) is a binary star system in the constellation Draco. Both stars are red dwarfs and both display variability common to flare stars. The orbital period for the pair is about 295 years, with an average distance of about 56 astronomical units,[4] and the eccentricity of the orbit is 0.70.

Struve 2398 is star number 2398 in the Struve Double Star Catalog of Baltic-German astronomer Friedrich Georg Wilhelm von Struve. The astronomer's surname, and hence the star identifier, is sometimes indicated by a Greek sigma, Σ.

X-ray source[edit]

Gliese 725 A and B are sources of X-rays.[5]

See also[edit]

References[edit]

  1. ^ a b c Rojas-Ayala, Bárbara et al. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs". The Astrophysical Journal 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93.  See Table 3.
  2. ^ Baize, P. (October 1976). "Orbital elements of eighteen visual double stars". Astronomy and Astrophysics, Supplemental Series 26: 177–193. Bibcode:1976A&AS...26..177B.  Listed as ADS 11632.
  3. ^ Mitchell Charity. What color are the stars?
  4. ^ "Struve 2398 AB". Retrieved 2010-10-22. 
  5. ^ Schmitt, J. H. M. M.; Fleming, T. A.; Giampapa, M. S. (September 1995). "The X-ray view of the low-mass stars in the solar neighborhood". The Astrophysical Journal 450 (9 pages=392–400). Bibcode:1995ApJ...450..392S. doi:10.1086/176149. 

External links[edit]