| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h 39m 34.61613s [1] |
| Declination | +10° 44′ 46.5827″ [1] |
| Apparent magnitude (V) | 5.57 [2] (6.35 + 6.47) [3] |
| Characteristics | |
| Evolutionary stage | Main sequence [4] [5] |
| Spectral type | F0V [6] |
| U−B color index | +0.045 [7] |
| B−V color index | +0.33 [7] |
| Astrometry | |
| Radial velocity (Rv) | −25.9±1.9 [8] km/s |
| Proper motion (μ) |
RA: −114.96
[1]
mas/
yr Dec.: −11.74 [1] mas/ yr |
| Parallax (π) | 16.67 ± 0.58 mas [1] |
| Distance | 196 ± 7
ly (60 ± 2 pc) |
| Absolute magnitude (MV) | +2.40 [9] |
| Orbit [10] | |
| Period (P) | 22.460±0.019 yr |
| Semi-major axis (a) | 0.19983±0.00055″ |
| Eccentricity (e) | 0.5450±0.0022 |
| Inclination (i) | 43.50±0.40° |
| Longitude of the node (Ω) | 34.58±0.52° |
| Periastron epoch (T) | B 1929.850±0.024 |
|
Argument of periastron (ω) (secondary) | 359.93±0.79° |
| Details | |
| A | |
| Mass | 1.89±0.03 M☉
[5] 1.41 [11] M☉ |
| Luminosity | 18.5 [5] L☉ |
| Surface gravity (log g) | 3.97 [11] cgs |
| Temperature | 7,080±241 [11] K |
| Rotational velocity (v sin i) | 144 [5] km/s |
| Age | 718 [11] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 118889 is a binary star system in the northern constellation of Boötes. It is faintly visible to the naked eye as a point of light with an apparent visual magnitude of 5.57. [2] The system is located at a distance of approximately 196 light years from the Sun based on stellar parallax, [1] but is drifting closer with a radial velocity of −26 km/s. [8]
The binary components of this system were first measured by S. W. Burnham in 1878 and it was given the discovery code BU 612. [12] The pair are orbiting each other with a period of 22.46 years with an eccentricity (ovalness) of 0.545. The primary component is a magnitude 6.35 [3] star with a stellar classification of F0V, [6] matching an F-type main-sequence star. It is an estimated 718 [11] million years old and is spinning rapidly with a projected rotational velocity of 144 [5] km/s. The star has 1.4–1.9 times the mass of the Sun. The secondary is slightly fainter at magnitude 6.47. [3]
References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752, Bibcode: 2007A&A...474..653V, doi: 10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971, Bibcode: 2012AstL...38..331A, doi: 10.1134/S1063773712050015, S2CID 119257644
- ^ a b c Malkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy & Astrophysics, 546: 5, Bibcode: 2012A&A...546A..69M, doi: 10.1051/0004-6361/201219774, A69
- ^ Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode: 2009A&A...493.1099S, doi: 10.1051/0004-6361:200810377[ permanent dead link]
- ^ a b c d e Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv: 1201.2052, Bibcode: 2012A&A...537A.120Z, doi: 10.1051/0004-6361/201117691, S2CID 55586789
- ^ a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv: astro-ph/0610785, Bibcode: 2007A&A...463..671R, doi: 10.1051/0004-6361:20065224, S2CID 18475298
- ^ a b Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode: 1986EgUBV........0M
- ^ a b Holmberg, J.; et al. (2007), "The Geneva-Copenhagen survey of the Solar neighbourhood. II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk", Astronomy & Astrophysics, 475 (2): 519–537, arXiv: 0707.1891, Bibcode: 2007A&A...475..519H, doi: 10.1051/0004-6361:20077221, S2CID 119054949
- ^ Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv: astro-ph/0509399, Bibcode: 2006A&A...446..267R, doi: 10.1051/0004-6361:20053911, S2CID 8642707
- ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 2021-04-01.
- ^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv: 1501.03154, Bibcode: 2015ApJ...804..146D, doi: 10.1088/0004-637X/804/2/146, S2CID 33401607
- ^ Mason, Brian D.; et al. (February 1999). "Binary Star Orbits from Speckle Interferometry. I. Improved Orbital Elements of 22 Visual Systems". The Astronomical Journal. 117 (2): 1023–1036. Bibcode: 1999AJ....117.1023M. doi: 10.1086/300748. S2CID 122382211.
External links
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h 39m 34.61613s [1] |
| Declination | +10° 44′ 46.5827″ [1] |
| Apparent magnitude (V) | 5.57 [2] (6.35 + 6.47) [3] |
| Characteristics | |
| Evolutionary stage | Main sequence [4] [5] |
| Spectral type | F0V [6] |
| U−B color index | +0.045 [7] |
| B−V color index | +0.33 [7] |
| Astrometry | |
| Radial velocity (Rv) | −25.9±1.9 [8] km/s |
| Proper motion (μ) |
RA: −114.96
[1]
mas/
yr Dec.: −11.74 [1] mas/ yr |
| Parallax (π) | 16.67 ± 0.58 mas [1] |
| Distance | 196 ± 7
ly (60 ± 2 pc) |
| Absolute magnitude (MV) | +2.40 [9] |
| Orbit [10] | |
| Period (P) | 22.460±0.019 yr |
| Semi-major axis (a) | 0.19983±0.00055″ |
| Eccentricity (e) | 0.5450±0.0022 |
| Inclination (i) | 43.50±0.40° |
| Longitude of the node (Ω) | 34.58±0.52° |
| Periastron epoch (T) | B 1929.850±0.024 |
|
Argument of periastron (ω) (secondary) | 359.93±0.79° |
| Details | |
| A | |
| Mass | 1.89±0.03 M☉
[5] 1.41 [11] M☉ |
| Luminosity | 18.5 [5] L☉ |
| Surface gravity (log g) | 3.97 [11] cgs |
| Temperature | 7,080±241 [11] K |
| Rotational velocity (v sin i) | 144 [5] km/s |
| Age | 718 [11] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 118889 is a binary star system in the northern constellation of Boötes. It is faintly visible to the naked eye as a point of light with an apparent visual magnitude of 5.57. [2] The system is located at a distance of approximately 196 light years from the Sun based on stellar parallax, [1] but is drifting closer with a radial velocity of −26 km/s. [8]
The binary components of this system were first measured by S. W. Burnham in 1878 and it was given the discovery code BU 612. [12] The pair are orbiting each other with a period of 22.46 years with an eccentricity (ovalness) of 0.545. The primary component is a magnitude 6.35 [3] star with a stellar classification of F0V, [6] matching an F-type main-sequence star. It is an estimated 718 [11] million years old and is spinning rapidly with a projected rotational velocity of 144 [5] km/s. The star has 1.4–1.9 times the mass of the Sun. The secondary is slightly fainter at magnitude 6.47. [3]
References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752, Bibcode: 2007A&A...474..653V, doi: 10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971, Bibcode: 2012AstL...38..331A, doi: 10.1134/S1063773712050015, S2CID 119257644
- ^ a b c Malkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy & Astrophysics, 546: 5, Bibcode: 2012A&A...546A..69M, doi: 10.1051/0004-6361/201219774, A69
- ^ Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode: 2009A&A...493.1099S, doi: 10.1051/0004-6361:200810377[ permanent dead link]
- ^ a b c d e Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv: 1201.2052, Bibcode: 2012A&A...537A.120Z, doi: 10.1051/0004-6361/201117691, S2CID 55586789
- ^ a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv: astro-ph/0610785, Bibcode: 2007A&A...463..671R, doi: 10.1051/0004-6361:20065224, S2CID 18475298
- ^ a b Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode: 1986EgUBV........0M
- ^ a b Holmberg, J.; et al. (2007), "The Geneva-Copenhagen survey of the Solar neighbourhood. II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk", Astronomy & Astrophysics, 475 (2): 519–537, arXiv: 0707.1891, Bibcode: 2007A&A...475..519H, doi: 10.1051/0004-6361:20077221, S2CID 119054949
- ^ Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv: astro-ph/0509399, Bibcode: 2006A&A...446..267R, doi: 10.1051/0004-6361:20053911, S2CID 8642707
- ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 2021-04-01.
- ^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv: 1501.03154, Bibcode: 2015ApJ...804..146D, doi: 10.1088/0004-637X/804/2/146, S2CID 33401607
- ^ Mason, Brian D.; et al. (February 1999). "Binary Star Orbits from Speckle Interferometry. I. Improved Orbital Elements of 22 Visual Systems". The Astronomical Journal. 117 (2): 1023–1036. Bibcode: 1999AJ....117.1023M. doi: 10.1086/300748. S2CID 122382211.
External links
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