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)	8.94/9.70
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 K
Metallicity [Fe/H]	-0.49 ± 0.17 dex
Struve 2398 B
Mass	0.30 M☉
Radius	0.54 R☉
Luminosity	0.021 L☉
Temperature	3,000 K
Orbit
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

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

References

^ ^a ^b ^c Rojas-Ayala, Bárbara; et al. (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. {{cite journal}}: Unknown parameter |month= ignored (help) See Table 3.
^ Baize, P. (1976). "Orbital elements of eighteen visual double stars". Astronomy and Astrophysics, Supplemental Series. 26: 177–193. Bibcode:1976A&AS...26..177B. {{cite journal}}: Unknown parameter |month= ignored (help) Listed as ADS 11632.
^ Mitchell Charity. What color are the stars?
^ "Struve 2398 AB". Retrieved 2010-10-22.
^ Schmitt, J. H. M. M.; Fleming, T. A.; Giampapa, M. S. (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. {{cite journal}}: Missing pipe in: |issue= (help); Unknown parameter |month= ignored (help)

External links

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[apj748_2_934-1] Rojas-Ayala, Bárbara; et al. (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. {{cite journal}}: Unknown parameter |month= ignored (help) See Table 3.

[aaass26-2] Baize, P. (1976). "Orbital elements of eighteen visual double stars". Astronomy and Astrophysics, Supplemental Series. 26: 177–193. Bibcode:1976A&AS...26..177B. {{cite journal}}: Unknown parameter |month= ignored (help) Listed as ADS 11632.

[3] Mitchell Charity. What color are the stars?

[SolStation-4] "Struve 2398 AB". Retrieved 2010-10-22.

[Schmitt-5] Schmitt, J. H. M. M.; Fleming, T. A.; Giampapa, M. S. (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. {{cite journal}}: Missing pipe in: |issue= (help); Unknown parameter |month= ignored (help)

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Observation data Epoch J2000 Equinox J2000
Constellation	Draco
Right ascension	18^h 42^m 46.7/46.9^s
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 (R_v)	–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 (M_V)	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

X-ray source

See also

References

External links