HD 130144

HD 130144 (or EK Boötis) is a semiregular variable star in the northern constellation of Boötes. The variation in luminosity has an amplitude of 0.38 in magnitude with no apparent periodicity. This is an X-ray source, and was possibly the first M-type giant star to have a magnetic field directly detected. It is considered to be a single star,[3] although there is nearby companion at an angular separation of 0.2023″ along a position angle of 82.2° (as of 2010.4812).[7]

HD 130144
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension  14h 46m 05.94566s[1]
Declination +15° 07′ 54.4332″[1]
Apparent magnitude (V) 5.82[2]
Characteristics
Spectral type M5III[3]
U−B color index +1.26[2]
B−V color index +1.50[2]
Variable type Lb[4]
Astrometry
Radial velocity (Rv)−22.52±0.65[5] km/s
Proper motion (μ) RA: −85.49[1] mas/yr
Dec.: +18.86[1] mas/yr
Parallax (π)4.04 ± 0.38[1] mas
Distance810 ± 80 ly
(250 ± 20 pc)
Details
Radius210±21[3] R☉
Luminosity5,587[6] L☉
Temperature3,333[6] K
Rotational velocity (v sin i)11[3] km/s
Other designations
EK Boötis, BD+15° 2758, FK5 3168, HD 130144, HIP 72208, HR 5512, SAO 101200.
Database references
SIMBADdata

References
  1. 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
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
  3. Konstantinova-Antova, R.; Aurière, M.; Charbonnel, C.; Drake, N. A.; Schröder, K.-P.; Stateva, I.; Alecian, E.; Petit, P.; Cabanac, R. (December 2010), "Direct detection of a magnetic field in the photosphere of the single M giant EK Bootis. How common is magnetic activity among M giants?", Astronomy and Astrophysics, 524: 9, arXiv:1009.2001, Bibcode:2010A&A...524A..57K, doi:10.1051/0004-6361/201014503, A57
  4. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  5. Famaey, B.; et al. (2009), "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698
  6. McDonald, I.; Zijlstra, A. A; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–57. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  7. Horch, Elliott P.; et al. (February 2011), "Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June" (PDF), The Astronomical Journal, 141 (2): 13, Bibcode:2011AJ....141...45H, doi:10.1088/0004-6256/141/2/45, 45


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