{{short description|Variable star in the constellation Taurus}} {{Starbox begin}} {{Starbox image | image = 250px | caption = A light curve for V1133 Tauri, plotted from ''TESS'' data.<ref name=MAST/> The 1.53 day period is marked in red. }} {{Starbox observe | epoch = J2000.0 | ra = {{RA|04|03|44.60445}}<ref name=dr3/> | dec = {{DEC|+05|26|08.2258}}<ref name=dr3/> | appmag_v = +5.33<ref name="Ducati2002"/> | constell = Taurus }} {{Starbox character | type = main sequence<ref name=dr3/> | class = B3V<ref name=lesh1968/> | b-v = | u-b = | variable = Slowly pulsating B<ref name="IVSI"/> }} {{Starbox astrometry | radial_v = | prop_mo_ra = {{val|1.271|0.275}}<ref name=dr3/> | prop_mo_dec = {{val|-7.216|0.201}}<ref name=dr3/> | parallax = 4.5161 | p_error = 0.2637 | parallax_footnote = <ref name=dr3/> | absmag_v = −1.2<ref name=schulz2019/> }} {{Starbox detail | source = <ref name="Sódor2014"/> | component1 = Primary | mass = 4.6 | radius = 2.4{{efn|name=radius}} | luminosity = {{val|560|530|270}} | temperature = {{val|fmt=commas|16850|800}} | metal_fe = −0.3 | gravity = {{val|4.2|0.2}} | rotational_velocity = {{val|21.5|1.5}} | rotation = {{val|5.9|2|ul=days}} | age_gyr = | component2 = Secondary | mass2 = 4.2 | radius2 = 2.9{{efn|name=radius}} | luminosity2 = {{val|420|540|230}} | temperature2 = {{val|fmt=commas|16250|1000}} | gravity2 = {{val|4.25|0.25}} | rotational_velocity2 = {{val|35|4}} | rotation2 = {{val|1.2|0.6|ul=days}} | metal_fe2 = −0.3 | age_myr2 = 40-55 }} {{Starbox catalog | names = 40 Tauri, V1133&nbsp;Tau, BD+05&nbsp;584, HIP&nbsp;18957, HR&nbsp;1253, SAO&nbsp;111585<ref name=SIMBAD/> }} {{Starbox reference | Simbad = 40+Tau }} {{Starbox end}}

'''HD 25558''', also known as '''V1133 Tauri''' and by its Flamsteed designation '''40 Tauri''', is a star located about 700 light years from the Earth, in the constellation Taurus.<ref name=dr3/> Its apparent magnitude is about 5.3,<ref name="Ducati2002"/> making it faintly visible to the naked eye of an observer far from city lights. It is a variable star, ranging in brightness from ''Hipparcos'' magnitude 5.28 to 5.32 over a period of 1.53232423 days.<ref name="IVSI"/>

In 1998, HD 25558 was discovered to be a variable star by Christoffel Waelkens ''et al.'' who analyzed the ''Hipparcos'' photometric data for hundreds of stars, and classified HD 25558 as a slowly pulsating B star with a period of 1.53 days.<ref name="Waelkens1998"/>

Beginning in 2008, HD 25558 was the subject of an observing campaign by Ádám Sódor ''et al.'' who gathered data collected from 17 observatories on the ground and in space. This star was chosen for the project because it is relatively bright, located near the celestial equator (and thus observable from almost anywhere on Earth), and the slow rotation indicated in earlier studies would simplify the interpretation of spectra. The investigators concluded that HD 25558 is a spectroscopic binary with a period of about 8.9 years, but not enough data was available to derive a full description of the orbit. Both components of the binary show detectable stellar pulsations. The primary star rotates with a period of about 6 days, and the secondary rotates in just 1.2 days. The primary has no detectable magnetic field, but the secondary's field strength is at least a few hundred gauss. The dominant 1.53 day pulsation period arises from the primary star and those pulsations were coherent over the 20 year period spanned by the data used in the study.<ref name="Sódor2014"/>

==Notes== {{notelist|refs= {{efn|name=radius|The paper derives the period from the rotational velocity and the radius, but does not show the radius. The radius found can be calculated from the period and equatorial rotational velocity.}} }}

==References== {{Reflist|30em|refs=

<ref name=schulz2019>{{cite journal | title=The magnetic early B-type Stars II: stellar atmospheric parameters in the era of Gaia | last1=Shultz | first1=M. E. | last2=Wade | first2=G. A. | last3=Rivinius | first3=Th | last4=Alecian | first4=E. | last5=Neiner | first5=C. | last6=Petit | first6=V. | last7=Wisniewski | first7=J. P. | last8=BinaMIcS Collaboration | display-authors=1 | journal=Monthly Notices of the Royal Astronomical Society | volume=485 | issue=2 | pages=1508–1527 | date=May 2019 | doi=10.1093/mnras/stz416 | doi-access=free | arxiv=1902.02713 | bibcode=2019MNRAS.485.1508S }}</ref>

<ref name=lesh1968>{{cite journal | last=Lesh | first=Janet Rountree |date=December 1968 | title=The Kinematics of the Gould Belt: an Expanding Group? | journal=Astrophysical Journal Supplement | volume=17 | page=371 | doi=10.1086/190179 | bibcode=1968ApJS...17..371L | doi-access=free }}</ref>

<ref name=MAST>{{cite web | title=MAST: Barbara A. Mikulski Archive for Space Telescopes | url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html | publisher=Space Telescope Science Institute |access-date=16 January 2023}}</ref>

<ref name=dr3>{{cite Gaia DR3|3272902041766301184}}</ref>

<ref name="Ducati2002">{{cite journal | last1=Ducati | first1=J. R. | title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system | url=https://cdsarc.cds.unistra.fr/viz-bin/cat/II/237#/browse | journal=Vizier Online Data Catalog | year=2002 | volume=2237 | bibcode=2002yCat.2237....0D | publisher=Strasbourg astronomical Data Center | access-date=17 January 2023}}</ref>

<ref name="IVSI">{{cite web | title=V1133 Tau | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=36150 | website=International Variable Star Index | publisher=AAVSO | access-date=17 January 2023}}</ref>

<ref name=SIMBAD>{{cite simbad | title=40 Tau -- Double or Multiple Star | access-date=2023-01-16}}</ref>

<ref name="Waelkens1998">{{cite journal | last1=Waelkens | first1=C. | last2=Aerts | first2=C. | last3=Kestens | first3=E. |last4=Grenon | first4=M. | last5=Eyer | first5=L. | title=Study of an unbiased sample of B stars observed with Hipparcos: the discovery of a large amount of new slowly pulsating B stars | journal=Astronomy and Astrophysics | date=February 1998 | volume=330 | pages=215–221 | bibcode=1998A&A...330..215W }}</ref>

<ref name="Sódor2014">{{cite journal | last1=Sódor | first1=Á. | last2=De Cat | first2=P. | last3=Wright | first3=D. J. | last4=Neiner | first4=C. | last5=Briquet | first5=M. | last6=Lampens | first6=P. | last7=Dukes | first7=R. J. | last8=Henry | first8=G. W. | last9=Williamson | first9=M. H. | last10=Brunsden | first10=E. | last11=Pollard | first11=K. R. | last12=Cottrell | first12=P. L. | last13=Maisonneuve | first13=F. | last14=Kilmartin | first14=P. M. | last15=Matthews | first15=J. | last16=Kallinger | first16=T. |last17=Beck | first17=P. G. | last18=Kambe | first18=E. | last19=Engelbrecht | first19=C. A. | last20=Czanik | first20=R. J. | last21=Yang | first21=S. | last22=Hashimoto | first22=O. | last23=Honda | first23=S. | last24=Fu | first24=J. N. | last25=Castanheira | first25=B. | last26=Lehmann | first26=H. | last27=Bognár | first27=Zs. | last28=Behara | first28=N. | last29=Scaringi | first29=S. | last30=Van Winckel | first30=H. | last31=Menu | first31=J. | last32=Lobel | first32=A. | last33=Mathias | first33=P. | last34=Saesen | first34=S. | last35=Vučković | first35=M. | last36=the MiMeS collaboration | title=Extensive study of HD 25558, a long-period double-lined binary with two SPB components | journal=Monthly Notices of the Royal Astronomical Society | date=March 2014 | volume=438 | issue=4 | pages=3535–3556 | doi=10.1093/mnras/stt2466 | arxiv=1312.6307 | bibcode=2014MNRAS.438.3535S | doi-access=free }}</ref>

}}

{{Stars of Taurus}}

Category:Slowly pulsating B-type stars Category:Taurus (constellation) 18957 25558 Category:Durchmusterung objects Tauri, V1133 Tauri, 40 Category:B-type main-sequence stars