Inverse (mathematics)

2013-12-15T23:00:55Z

71.116.229.228: Undid revision 586255593 by 71.116.229.228 (talk)

{{Starbox begin
| name = 98 Aquarii
}}
{{Starbox image
| image =
<div style="position: relative">[[File:Aquarius IAU.svg|250px|alt=Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings]]
<div style="position: absolute; left: 27.6%; top: 57.6%">[[File:Cercle rouge 100%.svg|12px]]</div>
</div>
| caption = Location of 98 Aquarii (circled)
}}
{{Starbox observe
| epoch = J2000
| ra = {{RA|23|22|58.22606}}<ref name=aaa474_2_653/>
| dec = {{DEC|–20|06|02.0963}}<ref name=aaa474_2_653/>
| appmag_v = +3.97<ref name=mnras172_667/>
| constell = [[Aquarius (constellation)|Aquarius]]
}}
{{Starbox character
| class = K0 III<ref name=houk1978/>
| b-v = +1.089<ref name=mnras172_667/>
| u-b = +0.948<ref name=mnras172_667/>
| variable =
}}
{{Starbox astrometry
| radial_v = –6.5<ref name=scfs/>
| prop_mo_ra = –121.28<ref name=aaa474_2_653/>
| prop_mo_dec = –97.59<ref name=aaa474_2_653/>
| parallax = 19.96
| p_error = 0.23
| parallax_footnote = <ref name=aaa474_2_653/>
| absmag_v =
}}
{{Starbox detail
| mass = 2.1<ref name=aaa439_1_227/>
| radius = 14<ref name=lang2006/>
| luminosity =
| gravity = 2.4<ref name=aaa439_1_227/>
| temperature = 4,630<ref name=aaa439_1_227/>
| metal_fe = –0.30<ref name=aaa439_1_227/>
| rotational_velocity =
| age_gyr =
}}
{{Starbox catalog
| names= b<sup>1</sup> Aquarii, [[Star catalogue#BD.2FCD.2FCPD|BD]]–20 6587, [[FK5]] 1612, [[Henry Draper Catalogue|HD]] 220321, [[Hipparcos catalogue|HIP]] 115438, [[Star catalogue#BS, BSC, HR|HR]] 8892, [[Star catalogue#SAO|SAO]] 191858.<ref name=SIMBAD/>
}}
{{Starbox end}}
'''98 Aquarii''' is the [[Flamsteed designation]] for a [[star]] in the [[celestial equator|equatorial]] [[constellation]] [[Aquarius (constellation)|Aquarius]]. The [[Bayer designation]] for this star is b<sup>1</sup> Aquarii. It is visible to the naked eye with an [[apparent visual magnitude]] of +3.97.<ref name=mnras172_667/> The distance to this star, {{Convert|163|ly|pc|abbr=off|lk=on}}, is known from [[parallax]] measurements made with the [[Hipparcos]] spacecraft.<ref name=aaa474_2_653/>

With over double the mass of the Sun,<ref name=aaa439_1_227/> this is an [[stellar evolution|evolved]] [[giant star]] that has a [[stellar classification]] of K0 III.<ref name=houk1978/> The measured [[angular diameter]] of this star is {{nowrap|2.54 ± 0.13 [[milliarcsecond|mas]]}}.<ref name=aaa431_773/> At the estimated distance of 98 Aquarii,<ref name=aaa474_2_653/> this yields a physical size of about 14 times the [[Solar radius|radius of the Sun]].<ref name=lang2006/> The expanded outer envelope has an [[effective temperature]] of 4,630 K,<ref name=aaa439_1_227/> giving it the orange glow of a [[K-type star]].<ref name=csiro/>

==References==
{{reflist|refs=

<ref name=aaa474_2_653>{{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | postscript=. |arxiv = 0708.1752 }}</ref>

<ref name=aaa439_1_227>{{citation | display-authors=1 | last1=Melo | first1=C. H. F. | last2=de Laverny | first2=P. | last3=Santos | first3=N. C. | last4=Israelian | first4=G. | last5=Randich | first5=S. | last6=Do Nascimento | first6=J. D., Jr. | last7=de Medeiros | first7=J. R. | title=On the nature of lithium-rich giant stars. Constraints from beryllium abundances | journal=Astronomy and Astrophysics | volume=439 | issue=1 | pages=227–235 |date=August 2005 | doi=10.1051/0004-6361:20041805 | bibcode=2005A&A...439..227M | arxiv=astro-ph/0504133 | postscript=. }}</ref>

<ref name=houk1978>{{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 | year=1978 | bibcode=1988mcts.book.....H | postscript=. }}</ref>

<ref name=scfs>{{citation | display-authors=1 | title=Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions | last1=Wielen | first1=R. | last2=Schwan | first2=H. | last3=Dettbarn | first3=C. | last4=Lenhardt | first4=H. | last5=Jahreiß | first5=H. | last6=Jährling | first6=R. | publisher=Astronomisches Rechen-Institut Heidelberg | issue=35 | year=1999 | bibcode=1999VeARI..35....1W | postscript=. }}</ref>

<ref name=mnras172_667>{{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=. }}</ref>

<ref name=SIMBAD>{{citation | title=98 Aqr -- Star | work=SIMBAD Astronomical Object Database | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=98+Aquarii | accessdate=2006-11-05 | postscript=. }}</ref>

<ref name=aaa431_773>{{citation | last1=Richichi | pages=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=. }}</ref>

<ref name=lang2006>{{citation | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3 | publisher=Birkhäuser | year=2006 | isbn=3-540-29692-1 | url=http://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 | postscript=. }}. The radius (R<sub>*</sub>) is given by:
:<math>\begin{align} 2\cdot R_*
& = \frac{(50.1\cdot 2.54\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 27.4\cdot R_{\bigodot}
\end{align}</math></ref>

<ref name=csiro>{{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=. }}</ref>

}}
{{Stars of Aquarius}}

[[Category:Flamsteed objects|Aquarii, 98]]
[[Category:Aquarius (constellation)]]
[[Category:K-type giants]]

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Inverse (mathematics)