Struve 2398

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)286.1 ± 1.8[2] mas
Distance11.40 ± 0.07 ly
(3.50 ± 0.02 pc)
Absolute magnitude (MV)11.20/11.96
Details
Struve 2398 A
Mass0.36 M☉
Radius0.55 R☉
Luminosity0.039 L☉
Temperature3,680 ± 18[1] K
Metallicity [Fe/H]-0.49 ± 0.17[1] dex
Struve 2398 B
Mass0.30 M☉
Radius0.54 R☉
Luminosity0.021 L☉
Temperature3,000 K
Orbit[3]
CompanionStruve 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
SIMBADdata
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
SIMBADdata

Struve 2398 (Gliese 725[4]) 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,[5] 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.

Distance

Struve 2398 distance estimates

Source Parallax, mas Distance, pc Distance, ly Distance, Pm Ref.
Woolley et al. (1970) 284±3 3.52±0.04 11.48±0.12 108.7+1.2
−1.1		 [6]
Gliese & Jahreiß (1991) 286.1±1.8 3.495±0.022 11.4±0.07 107.9±0.7 [2]
van Altena et al. (1995) 285.2±2.5 3.506+0.031
−0.03		 11.44±0.1 108.2+1
−0.9		 [7]
Perryman et al. (1997) (A) (Hipparcos) 280.28±2.57 3.57±0.03 11.64±0.11 110.1±1 [8]
Perryman et al. (1997) (B) (Hipparcos) 284.48±5.01 3.52±0.06 11.47+0.21
−0.2		 108.5±1.9 [8]
Perryman et al. (1997) (A) (Tycho) 348.70±22.70 2.87+0.2
−0.18		 9.4+0.7
−0.6		 88.5+6.2
−5.4		 [9]
Perryman et al. (1997) (B) (Tycho) 304.50±35.50 3.3+0.4
−0.3		 10.7+1.4
−1.1		 101.3+13.4
−10.6		 [9]
van Leeuwen (2007) (A) 280.18±2.18 3.569±0.028 11.64±0.09 110.1±0.9 [10]
van Leeuwen (2007) (B) 289.48±3.21 3.45±0.04 11.27+0.13
−0.12		 106.6±1.2 [10]
RECONS TOP100 (2009) 283.00±1.69[note 1] 3.534±0.021 11.52±0.07 109+0.7
−0.6		 [11]
RECONS TOP100 (2012) 283.83±1.46[note 2] 3.523±0.018 11.49±0.06 108.7±0.6 [12]

Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.

X-ray source

Gliese 725 A and B are sources of X-rays.[13]

See also

References

  1. ↑ 1.0 1.1 1.2 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. ↑ 2.0 2.1 Gliese, W. and Jahreiß, H. (1991). "Gl 725". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-10-20.
  3. ↑ 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.
  4. ↑ Mitchell Charity. What color are the stars?
  5. ↑ "Struve 2398 AB". Retrieved 2010-10-22.
  6. ↑ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 725". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-10-20.
  7. ↑ Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 4330". The General Catalogue of Trigonometric Stellar Parallaxes (Fourth ed.). Retrieved 2014-10-20.
  8. ↑ 8.0 8.1 Perryman et al. (1997). "HIP 91768". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
  9. ↑ 9.0 9.1 Perryman et al. (1997). "HIP 91768". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
  10. ↑ 10.0 10.1 van Leeuwen F. (2007). "HIP 91768". Validation of the new Hipparcos reduction. Retrieved 2014-10-20.
  11. ↑
  12. ↑ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-10-20.
  13. ↑ 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.

Notes

  1. ↑ Weighted parallax based on parallaxes from van Altena et al. (1995) and Perryman (1997) for components A and B.
  2. ↑ Weighted parallax based on parallaxes from van Altena et al. (1995) and van Leeuwen (2007) for components A and B.

External links