View source for Astronomy:HR 178

{{Short description|Likely binary star in the constellation Andromeda}}
{{Starbox begin 
| name = HD 3883 
}}
{{Starbox observe 
| epoch = J2000 
| ra = {{RA|00|41|36.0370}}<ref name=Gaia>{{cite DR2|2806529032199025536}}</ref>
| dec = {{DEC|+24|37|44.43}}<ref name=Gaia/> 
| appmag_v = 6.046<ref name=TYCHO/>
| constell = [[Astronomy:Andromeda (constellation)|Andromeda]] 
}}
{{Starbox character 
| class = kA5hF1mF2<ref name=abt/>
| b-v = 0.287<ref name=TYCHO/>
| variable = suspected<ref name=AAVSO/>
}}
{{Starbox astrometry 
| radial_v = {{val|-15.60|0.9}}<ref name=Gontcharov2006/>
| prop_mo_ra = {{val|106.272|0.499}}<ref name=Gaia/> 
| prop_mo_dec = {{val|-12.324|0.306}}<ref name=Gaia/> 
| parallax = 8.0963 
| p_error = 0.2630
| parallax_footnote = <ref name=Gaia/> 
<!--| absmag_v = 6.326 unsourced -->
}}
{{Starbox orbit
| reference = <ref name=Malkov2012/>
| period = 21.26
| eccentricity = 0.5
| axis = 0.126
}}
{{Starbox detail
| source                 =   <!--[source url]-->
| component1             =   <!--Name of the first component-->
| mass                   =   2.44<ref name=Hui>{{Cite journal |last=Hui-Bon-Hoa |first=A. |date=June 2000 |title=Metal abundances of field A and Am stars |url=http://aas.aanda.org/10.1051/aas:2000207 |journal=Astronomy and Astrophysics Supplement Series |volume=144 |issue=2 |pages=203–209 |bibcode=2000A&AS..144..203H |doi=10.1051/aas:2000207 |issn=0365-0138 |s2cid=123151702|doi-access=free }}</ref>
| radius                 =   3.82<ref name=Gaia/>
| luminosity             =   45<ref name=Gaia/>
| luminosity_bolometric  =   <!--Luminosity (in solar luminosities), bolometric-->
| luminosity_visual      =   <!--Luminosity (in solar luminosities), visual (V)-->
| habitable_inner        =   <!--Inner limit to the star's habitable zone, where temperatures are 100˚ C-->
| habitable_outer        =   <!--Outer limit to the star's habitable zone, where temperatures are 0˚ C-->
| gravity                =   {{val|3.80|0.14}}<ref name=PASTEL/>
| temperature            =   {{val|7,800|200}}<ref name=PASTEL/>
| metal_fe               =   {{val|0.53|0.13}}<ref name=PASTEL/>
| rotation               =   <!--Rotation (no units provided by template)-->
| rotational_velocity    =   18<ref name=abt/>
| age                    =   <!--Age (in years)-->
| age_myr                =   <!--Age (in millions of years)-->
| age_gyr                =   <!--Age (in billions of years)-->
}}
{{Starbox catalog 
| names = [[Astronomy:Hipparcos#Published catalogues|HIP]] 3269, HD 3883, [[Astronomy:Durchmusterung|BD]]+23°94, [[Astronomy:Smithsonian Astrophysical Observatory Star Catalog|SAO]] 74200. 
}}
{{Starbox reference 
| Simbad = HD+3883 
}}
{{Starbox end}}
'''HR 178''' is a probable [[Astronomy:Binary star|binary star]] in the constellation [[Astronomy:Andromeda (constellation)|Andromeda]]. Located approximately {{convert|124|pc|ly}} distant, it is an evolved [[Astronomy:Am star|Am star]]<ref name="Buckhart"/> with a combined apparent magnitude of 6.06, meaning that it can only be seen with the naked eye on dark, clear nights. The star is suspected of variability, possibly varying between magnitudes 6.04 and 6.06.<ref name=AAVSO/> The variable magnitude period of HD 3883 is about 9.17 min.<ref name=Chagnon>{{Cite thesis |last=Chagnon |first=François |date=2009 |title=Searching for northern roap stars: the UBC-OAN photometric survey |url=https://doi.library.ubc.ca/10.14288/1.0099308 |journal=University of British Columbia |language=en |doi=10.14288/1.0099308 |s2cid=124888408}}</ref>

The spectrum of HR 178 has been extensively studied for establishing element abundances in the evolved Am stars. It is given a spectral class of kA5hF1mF2, meaning its spectral type is A5, F1, or F2, depending on the particular [[Physics:Spectral line|spectral line]]s examined.  The evolutionary stage of the star, and its mass determined from comparison with theoretical evolutionary tracks, is not precisely determined.  However, it is very close to the end of its [[Astronomy:Main sequence|main sequence]] evolution and the margin of error in its mass is only about {{solar mass|0.1|link=y}}.<ref name="Buckhart"/>

HR 178 has been suspected of being a binary star since 1938 when its spectrum was interpreted as being composite.<ref name=hynek/>  The pair were resolved using [[Physics:Speckle interferometry|speckle interferometry]] in 1983.<ref name=mcalister/>  The companion is modelled to be between 1.5 and 3 magnitudes fainter than the primary star.<ref name=bonneau/>  Although there have since been several failed attempts to resolve the pair, a tentative orbit has been calculated with a period of 21.26 years and an eccentricity of 0.5.<ref name=Malkov2012/>

==References==
{{reflist|refs=

<ref name=mcalister>{{cite journal|bibcode=1983ApJS...51..309M|title=Speckle interferometric measurements of binary stars. VIII|journal=The Astrophysical Journal Supplement Series|volume=51|pages=309|last1=McAlister|first1=H. A.|last2=Hendry|first2=E. M.|last3=Hartkopf|first3=W. I.|last4=Campbell|first4=B. G.|last5=Fekel|first5=F. C.|year=1983|doi=10.1086/190851}}</ref>

<ref name=bonneau>{{cite journal|bibcode=1984A&AS...58..729B|title=Observations d'etoiles doubles par interferometrie des tavelures AU T2m du PIC du Midi|journal=Astronomy and Astrophysics Supplement Series|volume=58|pages=729|last1=Bonneau|first1=D.|last2=Carquillat|first2=J. M.|last3=Vidal|first3=J. L.|year=1984}}</ref>

<ref name=hynek>{{cite journal|bibcode=1938CoPer...1...10H|title=A survey of stars with composite spectra|journal=Contributions of Perkins Observatory|volume=1|pages=10|last1=Hynek|first1=J. A.|year=1938}}</ref>

<ref name=TYCHO>{{citation
 | last1=Høg | first1=E. | last2=Fabricius | first2=C.
 | last3=Makarov | first3=V. V. | last4=Urban | first4=S.
 | last5=Corbin | first5=T. | last6=Wycoff | first6=G.
 | last7=Bastian | first7=U. | last8=Schwekendiek | first8=P.
 | last9=Wicenec | first9=A.
 | title=The Tycho-2 catalogue of the 2.5 million brightest stars 
 | journal=Astronomy & Astrophysics
 | volume=355 | pages=L27–L30 | year=2000
 | bibcode=2000A&A...355L..27H | postscript=. }}</ref>

<ref name=Gontcharov2006>{{citation
 | title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system
 | last1=Gontcharov | first1=G. A.
 | journal=Astronomy Letters
 | volume=32 | issue=11 | pages=759–771 | date=2006
 | bibcode=2006AstL...32..759G | doi=10.1134/S1063773706110065
 | arxiv=1606.08053 | s2cid=119231169 | postscript=. }}</ref>

<ref name=AAVSO>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=38882 |title=NSV 258 |author=VSX|date=18 January 2010|work=AAVSO Website|publisher=[[Organization:American Association of Variable Star Observers|American Association of Variable Star Observers]]|access-date=15 June 2013}}</ref>

<ref name="Buckhart">{{Cite journal | doi = 10.1051/0004-6361:20040467| title = The field Am and ρ Puppis-like stars: Lithium and heavier elements| journal = Astronomy and Astrophysics| volume = 429| issue = 3| pages = 1043| year = 2005| last1 = Burkhart | first1 = C.| last2 = Coupry | first2 = M. F.| last3 = Faraggiana | first3 = R.| last4 = Gerbaldi | first4 = M.|bibcode = 2005A&A...429.1043B | doi-access = free}}</ref>

<ref name=PASTEL>{{citation
 | last1=Soubiran | first1=Caroline | last2=Le Campion | first2=Jean-François
 | last3=Brouillet | first3=Nathalie | last4=Chemin | first4=Laurent
 | title=The PASTEL catalogue: 2016 version
 | journal=Astronomy & Astrophysics | display-authors=1
 | volume=591 | pages=A118 | year=2016
 | bibcode=2016A&A...591A.118S | doi=10.1051/0004-6361/201628497
 | arxiv=1605.07384 | s2cid=119258214 | postscript=. }}</ref>

<ref name=Malkov2012>{{cite journal| doi=10.1051/0004-6361/201219774| title=Dynamical masses of a selected sample of orbital binaries| journal=Astronomy & Astrophysics| volume =546| pages=5| year =2012| last1 =Malkov | first1 = O. Yu.| last2 = Tamazian | first2 =V. S.| last3 = Docobo | first3 = J. A.| last4 = Chulkov | first4 = D. A.|bibcode=2012A&A...546A..69M| doi-access =free}}</ref>

<ref name=abt>{{cite journal|bibcode=1995ApJS...99..135A|title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars|journal=The Astrophysical Journal Supplement Series|volume=99|pages=135|last1=Abt|first1=Helmut A.|last2=Morrell|first2=Nidia I.|year=1995|doi=10.1086/192182|doi-access=free}}</ref>

}}

{{Stars of Andromeda}}

[[Category:Andromeda (constellation)]]
[[Category:Henry Draper Catalogue objects|003883]]
[[Category:Am stars]]
[[Category:Bright Star Catalogue objects|0178]]
[[Category:Suspected variables]]
[[Category:Hipparcos objects|003269]]
[[Category:Durchmusterung objects]]

{{Sourceattribution|HR 178}}