Astronomy:Upsilon Aquarii

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Upsilon Aquarii
Aquarius IAU.svg
Red circle.svg
Location of υ Aquarii (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquarius
Right ascension  22h 34m 41.63670s[1]
Declination –20° 42′ 29.5745″[1]
Apparent magnitude (V) +5.21[2]
Characteristics
Spectral type F7 V[3]
B−V color index +0.44[2]
Astrometry
Radial velocity (Rv)−2.28±0.51[1] km/s
Proper motion (μ) RA: +220.383[1] mas/yr
Dec.: –147.225[1] mas/yr
Parallax (π)43.5816 ± 0.1436[1] mas
Distance74.8 ± 0.2 ly
(22.95 ± 0.08 pc)
Absolute magnitude (MV)+3.44[4]
Details
A
Mass1.4[5] M☉
Radius1.49+0.04
−0.06[1] R☉
Luminosity3.581±0.17[1] L☉
Surface gravity (log g)4.11[6] cgs
Temperature6,514±118[1] K
Metallicity [Fe/H]0.08[5] dex
Rotational velocity (v sin i)34.9[7] km/s
Age900 Ma[4]
250+750
−50[5] Myr
Other designations
υ Aqr, 59 Aquarii, BD−21 6251, FK5 849, HD 213845, HIP 111449, HR 8592, SAO 191235[8]
Database references
SIMBADdata

Upsilon Aquarii, Latinized from υ Aquarii, is the Bayer designation for a binary star[9] system in the equatorial constellation of Aquarius. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.21.[2] Parallax measurements give a distance estimate of 74.8 light-years (22.9 parsecs) from Earth.[1] This is a high proper-motion star[8] that is drifting closer to the Sun with a radial velocity of –2.3 km/s.[1] It is part of the Hercules-Lyra association.[9]

The primary component is an F-type main sequence star with a stellar classification of F7 V.[3] It is less than a billion[4][5] years old and is spinning with a projected rotational velocity of 35 km/s.[7] The star has 1.4[5] times the mass of the Sun and 1.5[1] times the Sun's radius. It is radiating 3.6[1] times the Sun's luminosity from its photosphere at an effective temperature of 6,597 K,[6] giving it the yellow-white hue of an F-type star.[10]

The star displays an excess of near infrared radiation, suggesting it has a circumstellar disk of dusty debris.[11] This disk has a mean temperature of 75±17 K and is orbiting at an estimated radius of 84±41 astronomical unit|AU.[12] A faint stellar companion was detected in 2007 at the Gemini Observatory, with a separation of 6.09″±0.03″ from the primary.[9] This is equivalent to a physical projected separation of 139 astronomical unit|AU, which yields an estimated orbital period of ~1,330 years.[13] The debris disk is orbiting close to the dynamically unstable region of this system.[12]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J. 
  3. ↑ 3.0 3.1 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode: 1988mcts.book.....H. 
  4. ↑ 4.0 4.1 4.2 Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics 418: 989–1019, doi:10.1051/0004-6361:20035959, Bibcode: 2004A&A...418..989N. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Vigan, A. et al. (July 2017), "The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits. IV. Gravitational instability rarely forms wide, giant planets", Astronomy & Astrophysics 603: 19, doi:10.1051/0004-6361/201630133, A3, Bibcode: 2017A&A...603A...3V. 
  6. ↑ 6.0 6.1 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G. 
  7. ↑ 7.0 7.1 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", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode: 2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 [yes|permanent dead link|dead link}}]
  8. ↑ 8.0 8.1 "* ups Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+ups+Aqr. 
  9. ↑ 9.0 9.1 9.2 Lafrenière, David et al. (2007), "The Gemini Deep Planet Survey", The Astrophysical Journal 670 (2): 1367–1390, doi:10.1086/522826, Bibcode: 2007ApJ...670.1367L. 
  10. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-07-02. 
  11. ↑ Ertel, S. et al. (October 2014), "A near-infrared interferometric survey of debris-disk stars. IV. An unbiased sample of 92 southern stars observed in H band with VLTI/PIONIER", Astronomy & Astrophysics 570: 20, doi:10.1051/0004-6361/201424438, A128, Bibcode: 2014A&A...570A.128E. 
  12. ↑ 12.0 12.1 Yelverton, Ben; Kennedy, Grant M.; Su, Kate Y. L.; Wyatt, Mark C. (2019), "A statistically significant lack of debris discs in medium separation binary systems", Monthly Notices of the Royal Astronomical Society 488 (3): 3588–3606, doi:10.1093/mnras/stz1927, Bibcode: 2019MNRAS.488.3588Y. 
  13. ↑ Rodriguez, David R. et al. (May 2015), "Stellar multiplicity and debris discs: an unbiased sample", Monthly Notices of the Royal Astronomical Society 449 (3): 3160–3170, doi:10.1093/mnras/stv483, Bibcode: 2015MNRAS.449.3160R. 

External links



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