U Aquilae
Observation data EpochJ2000EquinoxJ2000 | |
---|---|
Constellation | Aquila |
Right ascension | 19h29m21.3603s[2] |
Declination | −07° 02′ 38.710″[2] |
Apparent magnitude(V) | 6.61[3](6.08 - 6.86[4]) |
Characteristics | |
Spectral type | F5-G1 I-II[5]+ B9.8V[6] |
U−Bcolor index | 0.70[3] |
B−Vcolor index | 1.10[3] |
Variable type | δ Cep[4] |
Astrometry | |
Radial velocity(Rv) | -6.5[2]km/s |
Proper motion(μ) | RA:-0.99[2]mas/yr Dec.:-9.14[2]mas/yr |
Parallax(π) | 3.63 ± 0.96mas[2] |
Distance | 614[6]pc |
Absolute magnitude(MV) | −3.68[6] |
Orbit[7] | |
Period(P) | 1,856 |
Semi-major axis(a) | 1.311 " (6.1 AU) |
Eccentricity(e) | 0.165 |
Inclination(i) | 74° |
Longitude of the node(Ω) | 190° |
Details | |
A | |
Mass | 5.7[6]M☉ |
Radius | 55[7]R☉ |
Luminosity | 2,570[6]L☉ |
Surface gravity(logg) | 1.3[8]cgs |
Temperature | 5,440-6,640[8]K |
Metallicity[Fe/H] | 0.17[9]dex |
B | |
Mass | 2.3[6]M☉ |
Radius | 2.1[7]R☉ |
Temperature | 9,300[7]K |
Other designations | |
Database references | |
SIMBAD | data |
U Aquilaeis abinary starsystem in the constellationAquila,Located approximately 614 parsecs (2,000 ly) away from Earth.
The primary star (component A) is ayellow supergiantwith a radius of 55R☉and a luminosity of 2,570L☉.The secondary (component B) is ablue main-sequence star,twice the mass of the sun and around thirty times more luminous. It is hotter than the primary star at 9,300 K, but much smaller and fainter. The two stars orbit every five years and their separation varies from five to sevenastronomical unitsin a mildly eccentric orbit.
u Aql A is aclassical Cepheidvariable starranging between magnitudes 6.08 and 6.86 over a period of 7.02 days. It is an evolved star which has exhausted its core hydrogen and is now fusing helium into carbon.[10]
References
[edit]- ^Kiss, Laszlo L. (July 1998)."A photometric and spectroscopic study of the brightest northern Cepheids - I. Observations".Monthly Notices of the Royal Astronomical Society.297(3): 825.Bibcode:1998MNRAS.297..825K.doi:10.1046/j.1365-8711.1998.01559.x.
- ^abcdefVan 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.S2CID18759600.
- ^abcDucati, 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.
- ^abSamus, 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.
- ^Simpson, P. (2012). "The Eagle and its Errands".Guidebook to the Constellations.Patrick Moore's Practical Astronomy Series. pp. 373–399.doi:10.1007/978-1-4419-6941-5_9.ISBN978-1-4419-6940-8.
- ^abcdefEvans, Nancy Remage (2013). "Binary Cepheids: Separations and Mass Ratios in 5M☉Binaries".The Astronomical Journal.146(4): 93.arXiv:1307.7123.Bibcode:2013AJ....146...93E.doi:10.1088/0004-6256/146/4/93.S2CID34133110.
- ^abcdWelch, 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.Bibcode:1987PASP...99..610W.doi:10.1086/132022.
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:CS1 maint: multiple names: authors list (link) - ^abKiss, 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.Bibcode:1998MNRAS.300..616K.doi:10.1046/j.1365-8711.1998.01943.x.
- ^Groenewegen, M. A. T. (2013). "Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity".Astronomy & Astrophysics.550:A70.arXiv:1212.5478.Bibcode:2013A&A...550A..70G.doi:10.1051/0004-6361/201220446.S2CID118665355.
- ^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): 825–838.Bibcode:1998MNRAS.297..825K.doi:10.1046/j.1365-8711.1998.01559.x.