Furuhjelm 46

Furuhjelm 46
Observation data; Epoch J2000 Equinox J2000
Constellation	Hercules
Right ascension	17h 12m 07.91s
Declination	+45° 39′ 57.2″
Apparent magnitude (V)	10.02/10.25
Characteristics
Spectral type	M3 + M3.5
Astrometry
Radial velocity (Rv)	–19 ± 5 km/s
Proper motion (μ)	RA: +348.59 ± 5.68 mas/yr ; Dec.: –1624.84 ± 6.80 mas/yr
Parallax (π)	156.66 ± 1.37[1] mas
Distance	20.8 ± 0.2 ly ; (6.38 ± 0.06 pc)
Orbit[2]
Period (P)	12.9512 ± 0.0096 yr
Semi-major axis (a)	0.7620 ± 0.0015″
Eccentricity (e)	0.7430 ± 0.008
Inclination (i)	149.14 ± 0.25°
Longitude of the node (Ω)	160.0 ± 1.3°
Periastron epoch (T)	1991.032 ± 0.011[3]
Argument of periastron (ω); (secondary)	99.0 ± 1.0°
Details
Temperature	3,272 ± 28[4] K
Metallicity [Fe/H]	–0.31 ± 0.17[4] dex
Other designations
	BD+45° 2505, HD 155876, HIP 84140, WDS 17121+5450, KUI 79
	Gl 661 A: LFT 1326, LTT 15095, LHS 433, NLTT 44362
	Gl 661 B: LFT 1327, LTT 15096, LHS 434, NLTT 44363
Database references
SIMBAD	The system
	A
	B

Furuhjelm 46, also known as HD 155876 and Gliese 661, is a nearby binary star system, consisting of two very similar red dwarfs, located in the constellation Hercules.

Furuhjelm 46 is the nearest "true" (i. e. not brown dwarf) star system in Hercules, however, there is brown dwarf in this constellation, located closer: WISE 1741+2553.

References

Söderhjelm, Staffan (1999). "HIP 84140". Visual binary orbits and masses post Hipparcos.
From the Sixth Catalog of Orbits of Visual Binary Stars, based upon Hartkopf, W. I.; Mason, B. D.; McAlister, H. A. (1996), "Binary star orbits from speckle interferometry. VIII. Orbits of 37 close visual systems", Astronomical Journal, 111: 370–392, Bibcode:1996AJ....111..370H, doi:10.1086/117790
Fractional Besselian year.
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" (PDF). The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93. S2CID 41902340.

External links

Diagram of orbit from U.S.Naval Obs. site

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[Söderhjelm1999-1] Söderhjelm, Staffan (1999). "HIP 84140". Visual binary orbits and masses post Hipparcos.

[aj111_370-2] From the Sixth Catalog of Orbits of Visual Binary Stars, based upon Hartkopf, W. I.; Mason, B. D.; McAlister, H. A. (1996), "Binary star orbits from speckle interferometry. VIII. Orbits of 37 close visual systems", Astronomical Journal, 111: 370–392, Bibcode:1996AJ....111..370H, doi:10.1086/117790

[3] Fractional Besselian year.

[apj748_2_934-4] 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" (PDF). The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93. S2CID 41902340.