44 Boötis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 15h 03m 47.29565s[1] |
| Declination | +47° 39′ 14.6228″[1] |
| Apparent magnitude (V) | 4.75[2] (5.136 / 6.004)[3] |
| Characteristics | |
| Spectral type | G0Vnv[4] + (K0V + K4V)[5] |
| U−B color index | 0.09[2] |
| B−V color index | 0.65[2] |
| Variable type | W UMa |
| Astrometry | |
| Radial velocity (Rv) | -17.89[6] km/s |
| Proper motion (μ) | RA: -445.84[1] mas/yr Dec.: 19.86[1] mas/yr |
| Parallax (π) | 78.39 ± 1.03[7] mas |
| Distance | 41.6 ± 0.5 ly (12.8 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.211[7] |
| Orbit[8] | |
| Primary | 44 Boo A |
| Period (P) | 209.8 ± 3.3 yr |
| Semi-major axis (a) | 3.666 ± 0.021″ |
| Eccentricity (e) | 0.5111 ± 0.0065 |
| Inclination (i) | 83.55 ± 0.05° |
| Longitude of the node (Ω) | 57.14 ± 0.06° |
| Periastron epoch (T) | B 2012.04 ± 0.26 |
| Argument of periastron (ω) (secondary) | 39.86 ± 0.68° |
| Details | |
| 44 Boo A | |
| Mass | 1.04 ± 0.10[8] M☉ |
| Luminosity | 1.552[3] L☉ |
| Surface gravity (log g) | 4.33[9] cgs |
| Temperature | 5,877[9] K |
| Metallicity [Fe/H] | -0.24[9] dex |
| Age | 1.4–1.5[10] Gyr |
| 44 Boo B | |
| Mass | 1.28 ± 0.02[8] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
44 Boötis or i Boötis is a triple star system in the constellation Boötes. It is approximately 41.6 light years from Earth.
The primary component, 44 Boötis A, is a yellow-white G-type main sequence dwarf with a mean apparent magnitude of +4.83. The companion component, 44 Boötis B, is a W Ursae Majoris variable spectroscopic binary. The variability of this star system was discovered by English astronomer William Herschel.[12] The brightness of the binary varies from magnitude +5.8 to +6.40 with a period of 6.43 hours. The components of the eclipsing binary are separated by 0.008 astronomical units (au), roughly 3 times the distance of the Moon from Earth, and close enough to allow their stellar envelopes to overlap.
The 44 Boötis system is 42 light-years (13 parsecs) from Earth.[7] It also may show signs of an infrared excess, implying the existence of a dust disk that absorbs visible light and re-emits it as infrared light. The dust would have a blackbody temperature of about 23 K, situated up to 182 au from the parent star.[3]
References
- 1 2 3 4 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752
, doi:10.1051/0004-6361:20078357. - 1 2 3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M.
- 1 2 3 Montesinos, B.; et al. (September 2016), "Incidence of debris discs around FGK stars in the solar neighbourhood", Astronomy & Astrophysics, 593: 31, Bibcode:2016A&A...593A..51M, doi:10.1051/0004-6361/201628329, A51.
- ↑ Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
- ↑ Zasche, P.; Wolf, M.; Hartkopf, W. I.; Svoboda, P.; Uhlař, R.; Liakos, A.; Gazeas, K. (2009). "A Catalog of Visual Double and Multiple Stars with Eclipsing Components". The Astronomical Journal. 138 (2): 664. Bibcode:2009AJ....138..664Z. arXiv:0907.5172 . doi:10.1088/0004-6256/138/2/664.
- ↑ Bilir, S.; et al. (February 2005), "Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation", Monthly Notices of the Royal Astronomical Society, 357 (2): 497–517, Bibcode:2005MNRAS.357..497B, arXiv:astro-ph/0411291 , doi:10.1111/j.1365-2966.2005.08609.x.
- 1 2 3 Eker, Z.; et al. (2009), "New absolute magnitude calibrations for W Ursa Majoris type binaries", Astronomische Nachrichten, 330 (1): 68–77, Bibcode:2009AN....330...68E, arXiv:0807.4989 , doi:10.1002/asna.200811041.
- 1 2 3 Zirm, Henry (2011). "The Rapid Convergence of 44 Boötis with Revised Orbit and Updated Ephemerides" (PDF). Journal of Double Star Observations. 7 (1): 24–36. Bibcode:2011JDSO....7...24Z.
- 1 2 3 Ramírez, I.; et al. (September 2012), "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets", The Astrophysical Journal, 756 (1): 46, Bibcode:2012ApJ...756...46R, arXiv:1207.0499 , doi:10.1088/0004-637X/756/1/46.
- ↑ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, Bibcode:2008ApJ...687.1264M, arXiv:0807.1686 , doi:10.1086/591785.
- ↑ "i Boo -- Eclipsing binary of W UMa type (contact binary)", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2015-04-22.
- ↑ Percy, John R. (2007), Understanding Variable Stars, Cambridge University Press, p. 3, ISBN 1139463284.