View source for Sigma Andromedae

{{Starbox begin
 | name=Sigma Andromedae
}}
{{Starbox image
 | image = 
     <div style="position: relative">[[File:Andromeda IAU.svg|250px|alt=Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings]]
     <div style="position: absolute; left: 57.2%; top: 49.5%;">[[File:Cercle rouge 100%.svg|12px]]</div>
     </div>
 | caption=Location of σ Andromedae (circled)
}}
{{Starbox observe
 | epoch       = [[J2000.0]]
 | ra          = {{RA|00|18|19.65745}}<ref name=aaa474_2_653/>
 | dec         = {{DEC|+36|47|06.8107}}<ref name=aaa474_2_653/>
 | appmag_v    = +4.51<ref name=scfs/>
 | constell    = [[Andromeda (constellation)|Andromeda]]
}}
{{Starbox character
 | class       = A2&nbsp;V<ref name=aj74_375/>
 | b-v         = +0.05<ref name=clpl4_99/>
 | u-b         = +0.07<ref name=clpl4_99/>
 | variable    = 
}}
{{Starbox astrometry
 | radial_v    = –8.0<ref name=scfs/>
 | prop_mo_ra  = –65.67<ref name=aaa474_2_653/>
 | prop_mo_dec = -42.00<ref name=aaa474_2_653/>
 | parallax    = 24.20
 | p_error     = 0.21
 | parallax_footnote=<ref name=aaa474_2_653/>
 | absmag_v    = 1.33<ref name=aj125_4_1980/>
}}
{{Starbox detail
 | component1  = 
 | mass        = 
 | radius      = 2.1<ref name=lang2006/>
 | luminosity  = 26<ref name=apjss176_1_276/>
 | temperature = 8,929<ref name=aj125_4_1980/>
 | metal_fe    = 
 | gravity     = 4.02<ref name=aj125_4_1980/>
 | age_myr     = 450<ref name=aj143_6_135/>
 | rotational_velocity = 123<ref name=aaa463_2_671/>
}}
{{Starbox catalog
 | names=25&nbsp;Andromeda, [[Star catalogue#BD.2FCD.2FCPD|BD]]+35°44, [[FK5]]&nbsp;1005, [[Henry Draper Catalogue|HD]]&nbsp;1404, [[Hipparcos catalogue|HIP]]&nbsp;1473, [[Star catalogue#BS, BSC, HR|HR]]&nbsp;68, [[Star catalogue#SAO|SAO]]&nbsp;53798.<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad=sig+And
}}
{{Starbox end}}
'''Sigma Andromedae''' (σ And, σ Andromedae) is the [[Bayer designation]] for a [[star]] in the northern [[constellation]] of [[Andromeda (constellation)|Andromeda]]. It has an [[apparent visual magnitude]] of +4.5,<ref name=scfs/> which is bright enough to be seen with the naked eye from [[Bortle Dark-Sky Scale|most locations]]. [[Parallax]] measurements made during the [[Hipparcos]] mission place it at a distance of about {{Convert|135|ly|pc|abbr=off|lk=on}}.<ref name=aaa474_2_653/> The magnitude of the star is diminished by 0.08 from [[Extinction (astronomy)|extinction]] caused by intervening gas and dust.<ref name=apjss176_1_276/>

This star has a [[stellar classification]] of A2&nbsp;V,<ref name=aj74_375/> which matches the [[stellar spectrum|spectrum]] of an [[A-type main sequence star]]. It is about 450 million years old<ref name=aj143_6_135/> and is spinning rapidly with a [[projected rotational velocity]] of 123&nbsp;km/s.<ref name=aaa463_2_671/> The [[interferometry]]-measured [[angular diameter]] of this star is 0.465&nbsp;[[milliarcseconds|mas]],<ref name=apjss176_1_276/> which, at its estimated distance, equates to a physical radius of about 2.1 times the [[Solar radius|radius of the Sun]].<ref name=lang2006/> It is radiating 26<ref name=apjss176_1_276/> times the luminosity of the Sun from its [[stellar atmosphere|outer atmosphere]] at a temperature of 8,929&nbsp;K,<ref name=aj125_4_1980/> giving it the white-hued glow of an [[A-type star]].<ref name=csiro/>

In the past, [[radial velocity]] variations have been reported, but this remains unconfirmed.{{citation needed|date=September 2018}} The star does not show any significant [[variable star|photometric variations]] and is used as a [[UBV photometric system|ubvy standard star]].<ref name=aaa300_783/> A [[debris disk]] of warm dust around this star has been detected by [[Spitzer Space Telescope]].<ref name=apj699_2_2009/>

Sigma Andromedae is a candidate for membership in the stream of stars associated with the [[Ursa Major Moving Group]]. This is a set of stars that share a common motion through space, which suggests they originated together.<ref name=aj125_4_1980/>

==Naming==
In [[Chinese astronomy|Chinese]], {{lang|zh|天廄}} ({{lang|zh-Latn|Tiān Jiù}}), meaning ''[[Wall (Chinese constellation)|Celestial Stable]]'', refers to an asterism consisting of σ Andromedae, [[Theta Andromedae|θ Andromedae]] and [[Rho Andromedae|ρ Andromedae]]. Consequently, the [[Chinese star names|Chinese name]] for σ Andromedae itself is {{lang|zh|天廄三}} ({{lang|zh-Latn|Tiān Jiù sān}}, {{lang-en|the Third Star of Celestial Stable}}.)<ref>{{zh icon}} [http://aeea.nmns.edu.tw/2006/0605/ap060518.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日]</ref>

==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=aj74_375>{{citation | display-authors=1 | last1=Cowley | first1=A. | last2=Cowley | first2=C. | last3=Jaschek | first3=M. | last4=Jaschek | first4=C. | title=A study of the bright A stars. I. A catalogue of spectral classifications | journal=Astronomical Journal | volume=74 | pages=375–406 |date=April 1969 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C | postscript=. }}</ref>

<ref name=scfs>{{citation | display-authors=1 | title=Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions | journal=Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg | volume=35 | 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 | pages=1 | date=1999 | bibcode=1999VeARI..35....1W | postscript=. }}</ref>

<ref name=aaa463_2_671>{{citation | last1=Royer | first1=F. | last2=Zorec | first2=J. | last3=Gómez | first3=A. E. | title=Rotational velocities of A-type stars. III. Velocity distributions | journal=Astronomy and Astrophysics | volume=463 | issue=2 | pages=671–682 |date=February 2007 | doi=10.1051/0004-6361:20065224 | bibcode=2007A&A...463..671R | arxiv=astro-ph/0610785 | postscript=. }}</ref>

<ref name=clpl4_99>{{citation | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | date=1966 | bibcode=1966CoLPL...4...99J | postscript=. }}</ref>

<ref name=aj143_6_135>{{citation | last1=Vican | first1=Laura | title=Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey | journal=The Astronomical Journal | volume=143 | issue=6 | page=135 |date=June 2012 | doi=10.1088/0004-6256/143/6/135 | bibcode=2012AJ....143..135V | postscript=. |arxiv = 1203.1966 }}</ref>

<ref name=apjss176_1_276>{{citation | display-authors=1 | last1=van Belle | first1=G. T. | last2=van Belle | first2=G. | last3=Creech-Eakman | first3=M. J. | last4=Coyne | first4=J. | last5=Boden | first5=A. F. | last6=Akeson | first6=R. L. | last7=Ciardi | first7=D. R. | last8=Rykoski | first8=K. M. | last9=Thompson | first9=R. R. | title=The Palomar Testbed Interferometer Calibrator Catalog | journal=The Astrophysical Journal Supplement Series | volume=176 | issue=1 | pages=276–292 |date=May 2008 | doi=10.1086/526548 | bibcode=2008ApJS..176..276V | postscript=. |arxiv = 0711.4194 }}</ref>

<ref name=lang2006>{{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 }}. The radius (R<sub>*</sub>) is given by:
:<math>\begin{align} 2\cdot R_*
 & = \frac{(41.3\cdot 0.465\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
 & \approx 4.13\cdot R_{\bigodot}
\end{align}</math></ref>

<ref name=aj125_4_1980>{{citation | display-authors=1 | last1=King | first1=Jeremy R. | last2=Villarreal | first2=Adam R. | last3=Soderblom | first3=David R. | last4=Gulliver | first4=Austin F. | last5=Adelman | first5=Saul J. | title=Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group | journal=The Astronomical Journal | volume=125 | issue=4 | pages=1980–2017 |date=April 2003 | doi=10.1086/368241 | bibcode=2003AJ....125.1980K | postscript=. }}</ref>

<ref name=SIMBAD>{{cite simbad | title=sig And | accessdate=2012-06-24 | postscript=. }}</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=2012-06-24 | postscript=. }}</ref>

<ref name=aaa300_783>{{citation | display-authors=1 | last1=Lehmann | first1=H. | last2=Scholz | first2=G. | last3=Hildebrandt | first3=G. | last4=Klose | first4=S. | last5=Panov | first5=K. P. | last6=Reimann | first6=H.-G. | last7=Woche | first7=M. | last8=Ziener | first8=R. | title=Variability investigations of possible Maia stars | journal=Astronomy and Astrophysics | volume=300 | page=783 |date=August 1995 | bibcode=1995A&A...300..783L }}</ref>

<ref name=apj699_2_2009>{{citation| display-authors=1 | last1=Morales | first1=F.Y. | last2= Werner | first2=M.W. | last3=Bryden | first3=G. | last4=Plavchan | first4=P. | last5=Stapelfeldt | first5=K.R. | last6=Rieke | first6=G.H. | last7=Su | first7=K.Y.L. | last8=Beichman | first8=C.A. | title=Spitzer Mid-IR Spectra of Dust Debris Around A and Late B Type Stars: Asteroid Belt Analogs and Power-Law Dust Distributions | journal=The Astrophysical Journal | volume=699 | issue=2 | page=1067–1086 |date=July 2009 | bibcode=2009ApJ...699.1067M | doi=10.1088/0004-637X/699/2/1067| url=https://authors.library.caltech.edu/15348/1/Morales2009p4714Astrophys_J.pdf }}</ref>

}}

{{Stars of Andromeda}}
<!-- Properties -->
[[Category:A-type main-sequence stars]]
[[Category:Ursa Major Moving Group]]
<!-- Identifiers -->
[[Category:Bayer objects|Andromedae, Sigma]]
[[Category:Andromeda (constellation)]]
[[Category:Durchmusterung objects]]
[[Category:Flamsteed objects|Andromedae, 25]]
[[Category:Henry Draper Catalogue objects|001404]]
[[Category:Hipparcos objects|001473]]
[[Category:HR objects|0068]]