U Aquilae

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U Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 29m 21.3603s[1]>
Declination −07° 02′ 38.710″[1]
Apparent magnitude (V) 6.61[2]
Characteristics
Spectral type F5-G1I-II[3] + B9.8V[4]
U−B color index 0.70[2]
B−V color index 1.10[2]
Variable type classical Cepheid[5]
Astrometry
Radial velocity (Rv) -6.5[1] km/s
Proper motion (μ) RA: -0.99[1] mas/yr
Dec.: -9.14[1] mas/yr
Parallax (π) 3.63 ± 0.96[1] absmag_v=-0.79 mas
Distance approx. 900 ly
(approx. 280 pc)
Details
Mass 7/2[6] M
Radius 55/2.1[6] R
Luminosity 2,570[4] L
Surface gravity (log g) 1.3[7] cgs
Temperature 5,440-6,640[7] K
Metallicity [Fe/H] 0.17[8] dex
Orbit
Companion U Aquilae B
Period (P) 1856[6] days
Semi-major axis (a) 1.311[6]"
Eccentricity (e) 0.17[6]
Inclination (i) 74[6]°
Longitude of the node (Ω) 190[6]°
Other designations
GCRV 11912, IDS 19240-0715 AB, TYC 5143-1372-1, KUI 91AB, IRAS 19266-0708, UBV M 23815, ADS 12503 AB, GSC 05143-01372, LS IV -07 35, UBV 21626, ALS 10306, HD 183344, 2MASS J19292135-0702387, uvby98 100183344 ABV, BD-07° 4968, HERZ 2291, PLX 4556, YZ 97 6771, CCDM J19294-0703AB, HIC 95820, PPM 202954, AAVSO 1924-07, CSI-07 4968 1, HIP 95820, SAO 143454, GC 26905, HR 7402.
Database references
SIMBAD data
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

U Aquilae is a binary star system[4] in the constellation Aquila. Located approximately 275 parsecs (900 ly) distant, the primary is a classical Cepheid variable ranging between magnitudes 6.08 and 6.86 over a period of 7.02 days,[5] while the secondary is a blue main-sequence star.[4]

References[edit]

  1. ^ a b c d e f Van Leeuwen, F. (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.  edit
  2. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237: 0. Bibcode:2002yCat.2237....0D. 
  3. ^ Simpson, P. (2012). "The Eagle and its Errands". Guidebook to the Constellations. Patrick Moore's Practical Astronomy Series. p. 373. doi:10.1007/978-1-4419-6941-5_9. ISBN 978-1-4419-6940-8.  edit
  4. ^ a b c d Evans, Nancy Remage (2013). "BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M ☉ BINARIES". The Astronomical Journal 146 (4): 93. doi:10.1088/0004-6256/146/4/93.  edit
  5. ^ a b Kiss, L. L. (1998). "A photometric and spectroscopic study of the brightest northern Cepheids -- I. Observations". Monthly Notices of the Royal Astronomical Society 297 (3): 825. doi:10.1046/j.1365-8711.1998.01559.x.  edit
  6. ^ a b c d e f g Welch, D. L.; Evans, N. R.; Lyons, R. W.; Harris, H. C.; Barnes, T. G. , I. I.; Slovak, M. H.; Moffett, T. J. (1987). "The orbit of the classical Cepheid U Aquilae". Publications of the Astronomical Society of the Pacific 99: 610. doi:10.1086/132022.  edit
  7. ^ a b Kiss, L. L.; Szatmary, K. (1998). "A photometric and spectroscopic study of the brightest northern Cepheids -- II. Fundamental physical parameters". Monthly Notices of the Royal Astronomical Society 300 (2): 616. doi:10.1046/j.1365-8711.1998.01943.x.  edit
  8. ^ Groenewegen, M. A. T. (2013). "Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity". Astronomy & Astrophysics 550: A70. doi:10.1051/0004-6361/201220446.  edit