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词条 99 Aquarii
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  1. References

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{{about|b2 Aquarii|other star systems with this Bayer designation|b Aquarii}}{{Starbox begin
| name = 99 Aquarii
}}{{Starbox image
| image =

| caption = Location of 99 Aquarii (circled)
}}{{Starbox observe
| epoch = J2000
| ra = {{RA|23|26|02.78566}}
| dec = {{DEC|–20|38|31.251}}
| appmag_v = 4.37[3]
| constell = Aquarius
}}{{Starbox character
| class = K4 III[4]
| b-v = +1.431[3]
| u-b = +1.815[3]
| variable = Suspected[7]
}}{{Starbox astrometry
| radial_v = +15.7[8]
| prop_mo_ra = –50.72
| prop_mo_dec = –64.22
| parallax = 11.51
| p_error = 0.21
| parallax_footnote =
| absmag_v =
}}{{Starbox detail
| mass =
| radius = 33[12]
| luminosity =
| temperature = 3980[13]
| metal_fe = –0.20[13]
| gravity = 1.66[13]
| rotational_velocity =
| age_myr =
}}{{Starbox catalog
| names= BD–21 6420, HD 220704, HIP 115669, HR 8906, NSV 14554, SAO 191900.[16]
}}{{Starbox reference|Simbad=99+Aqr}}{{Starbox end}}99 Aquarii (abbreviated 99 Aqr) is a star in the equatorial constellation of Aquarius. 99 Aquarii is the Flamsteed designation, although it also bears the Bayer designation b2 Aquarii. It is visible to the naked eye with an apparent visual magnitude of 4.38;[3] according to the Bortle Dark-Sky Scale this is bright enough to be seen even from city skies under ideal viewing conditions. Based upon parallax measurements, the distance to this star is around {{Convert|283|ly|pc|abbr=off|lk=on}}.

This is a giant star with a stellar classification of K4 III.[4] It is a suspected variable star that apparently ranges in magnitude between 4.35 and 4.45.[7] The measured angular diameter of this star is {{nowrap|3.55 ± 0.21 mas}}.[21] At the estimated distance of Delta Ophiuchi, this yields a physical size of about 33 times the radius of the Sun.[12] The outer atmosphere has an effective temperature of 3980 K,[13] giving it the orange-hued glow of a cool, K-type star.[25]

This star was a candidate member of the Ursa Major Moving Group based on the work of American astronomer Nancy Roman, but this membership is now in question.[26]

References

1. ^1 2 3 4 {{citation | last1=McWilliam | first1=Andrew | title=High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances | journal=Astrophysical Journal Supplement Series | volume=74 | pages=1075–1128 |date=December 1990 | doi=10.1086/191527 | bibcode=1990ApJS...74.1075M | postscript=. }}
2. ^1 2 {{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=4 | publication-place=Ann Arbor | publisher=Dept. of Astronomy, University of Michigan | date=1978 | bibcode=1988mcts.book.....H | postscript=. }}
3. ^1 {{citation | last=Wilson | first=Ralph Elmer | date=1953 | title=General Catalogue of Stellar Radial Velocities | publisher=Carnegie Institution of Washington | location=Washington | bibcode=1953GCRV..C......0W | postscript=. }}
4. ^1 2 3 4 {{citation | last1=Jennens | first1=P. A. | last2=Helfer | first2=H. L. | title=A new photometric metal abundance and luminosity calibration for field G and K giants. | journal=Monthly Notices of the Royal Astronomical Society | volume=172 | pages=667–679 |date=September 1975 | bibcode=1975MNRAS.172..667J | postscript=. | doi=10.1093/mnras/172.3.667}}
5. ^1 {{cite simbad | title=* 99 Aqr | accessdate=2012-07-11 | postscript=. }}
6. ^1 {{citation | last1=Richichi | first1=A. | last2=Percheron | first2=I. | last3=Khristoforova | first3=M. | title=CHARM2: An updated Catalog of High Angular Resolution Measurements | journal=Astronomy and Astrophysics | volume=431 | pages=773–777 |date=February 2005 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | postscript=. }}
7. ^1 2 {{citation | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3rd | publisher=Birkhäuser | date=2006 | isbn=3-540-29692-1 | url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 | postscript=. }}. The radius (R*) is given by::
8. ^1 {{citation|title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |accessdate=2012-01-16 |postscript=. |deadurl=yes |archiveurl=https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archivedate=March 10, 2012 }}
9. ^1 2 {{citation | display-authors=1 | last1=Samus | first1=N. N. | last2=Durlevich | first2=O. V. | last3=Kazarovets | first3=E. V. | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N. | last6=Zharova | first6=A .V. | title=NSV 14554 | work=General Catalog of Variable Stars |date=March 2012 | url=http://www.sai.msu.su/gcvs/cgi-bin/ident.cgi?cat=HD++&num=220704 | accessdate=2012-07-12 | postscript=. }}
10. ^1 {{citation | last1=Chupina | first1=N. V. | last2=Reva | first2=V. G. | last3=Vereshchagin | first3=S. V. | title=Kinematic structure of the corona of the Ursa Major flow found using proper motions and radial velocities of single stars | journal=Astronomy and Astrophysics | volume=451 | issue=3 | pages=909–916 |date=June 2006 | doi=10.1051/0004-6361:20054009 | bibcode=2006A&A...451..909C | postscript=. }} See table 7.
[1][2][3][4][5][6][7][8][9][10]
}}

External links

  • Image 99 Aquarii
{{Stars of Aquarius}}

10 : K-type giants|Suspected variables|Ursa Major Moving Group|Aquarius (constellation)|Bayer objects|Durchmusterung objects|Flamsteed objects|Henry Draper Catalogue objects|Hipparcos objects|HR objects
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