{{Short description|Star system in the constellation Taurus}} {{Starbox begin | name = LkCa 15 }} {{Starbox image | image = 250px | caption = LkCa 15 protoplanetary disk | credit = <!--credit for image if the image's use requires them (optional)--> }} {{Starbox observe | epoch = J2000.0 | constell = Taurus<ref>{{cite constellation|LkCa 15}}</ref> | ra = {{RA|04|39|17.796}}<ref name=SIMBAD>{{cite simbad|title=EM* LkCa 15}}</ref> | dec = {{DEC|+22|21|03.48}}<ref name=SIMBAD/> | appmag_v = +11.91<ref name=EU>{{cite encyclopedia|url=https://exoplanet.eu/catalog/lkca_15_b--1017/|title=Notes on LKCA 15 b|date=1995 |encyclopedia=Extrasolar Planets Encyclopaedia|access-date=26 December 2016}}</ref> }} {{Starbox character | class = K5V<ref name=EU/> | variable = T Tauri<ref name=SIMBAD/> }} {{Starbox astrometry | prop_mo_ra = 10.572<ref name=DR3/> | prop_mo_dec = -17.527<ref name=DR3/> | parallax = 6.3619 | p_error = 0.0264 | parallax_footnote = <ref name=DR3>{{cite Gaia DR3|144936836795636864}}</ref> | dist_ly = <!--Distance (in light years)--> | dist_pc = <!--Distance (in parsecs)--> | absmag_v = <!--Absolute magnitude (Johnson-Cousins V system)--> | absmag_bol = <!--Absolute bolometric magnitude (accounts for emissions across all spectra of light)--> }} {{Starbox detail | source = | age_myr = 2<ref name=EU/> | mass = 0.97 ± 0.03<ref name=EU/> | radius=1.2<ref name=Currie2019/> | temperature = 4730<ref name=Currie2019/> | luminosity = 1.22<ref name=Thalmann/> }} {{Starbox catalog | names = V1079 Tau, GSC 01278-00193, TYC 1278-193-1, 2MASS J04391779+2221034<ref name=SIMBAD/> }} {{Starbox reference | Simbad = EM*+LkCa+15 }} {{Starbox end }}
[[File:V1079TauLightCurve.png|thumb|left|A light curve for V1079 Tauri, adapted from Alencar ''et al.'' (2018)<ref name="Alencar"/>]] '''LkCa 15''' is a T Tauri star in the Taurus Molecular Cloud. These types of stars are relatively young pre-main-sequence stars that show irregular variations in brightness.<ref name=dd>{{cite web|url=http://www.daviddarling.info/encyclopedia/T/TTauri.html|title=Encyclopedia of Science: T Tauri star|accessdate=17 January 2017|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127063304/https://www.daviddarling.info/encyclopedia/T/TTauri.html|url-status=dead}}</ref> It has a mass that is about 97% of the Sun,<ref name=EU/> an effective temperature of 4370 K,<ref name=Thalmann>{{Cite journal|doi=10.1051/0004-6361/201322915|bibcode=2014A&A...566A..51T|arxiv=1402.1766|title=The architecture of the Lk ''Ca'' 15 transitional disk revealed by high-contrast imaging|journal=Astronomy & Astrophysics|volume=566|pages=A51|year=2014|last1=Thalmann|first1=C.|last2=Mulders|first2=G. D.|last3=Hodapp|first3=K.|last4=Janson|first4=M.|last5=Grady|first5=C. A.|last6=Min|first6=M.|last7=De Juan Ovelar|first7=M.|last8=Carson|first8=J.|last9=Brandt|first9=T.|last10=Bonnefoy|first10=M.|last11=McElwain|first11=M. W.|last12=Leisenring|first12=J.|last13=Dominik|first13=C.|last14=Henning|first14=T.|last15=Tamura|first15=M.|s2cid=34485844}}</ref> and is slightly cooler than the Sun. Its apparent magnitude is 11.91,<ref name=EU/> meaning it is not visible to the naked eye. Its name stems from an older survey.<ref>{{Cite journal|doi=10.1086/114039|bibcode=1986AJ.....91..575H|title=A spectroscopic survey of the Taurus-Auriga dark clouds for pre-main-sequence stars having CA II H, K emission|journal=The Astronomical Journal|volume=91|pages=575|year=1986|last1=Herbig|first1=G. H.|last2=Vrba|first2=F. J.|last3=Rydgren|first3=A. E.|doi-access=free}}</ref>
In 1993, Jérôme Bouvier ''et al.'' announced that LkCa 15 is a variable star.<ref name="AnA1993"/> It was given its variable star designation, V1079 Tauri, in 1995.<ref name="IBVS1995"/>
==Planetary system== LkCa 15 is surrounded by a protoplanetary disk, typical of many T Tauri stars.<ref name=dd/> The disk around the star is about 55 times more massive than Jupiter,<ref>{{Cite journal|doi=10.1086/432712|title=Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective|journal=The Astrophysical Journal|volume=631|issue=2|pages=1134–1160|year=2005|last1=Andrews|first1=Sean M.|last2=Williams|first2=Jonathan P.|arxiv = astro-ph/0506187 |bibcode = 2005ApJ...631.1134A |s2cid=17583379}}</ref> and consists of three major belts (components).<ref name=Currie2019/> Small changes in the observed brightness of the disk may be due to a planetary companion; the star was believed to have a protoplanetary object or exoplanet orbiting it, known as LkCa 15 b.<ref name="Kraus2012">{{Cite journal|doi=10.1088/0004-637x/745/1/5|title=LkCa 15: A Young Exoplanet Caught at Formation?|journal=The Astrophysical Journal|volume=745|pages=5|year=2012|last1=Kraus|first1=Adam L.|last2=Ireland|first2=Michael J.|issue=1|arxiv = 1110.3808 |bibcode = 2012ApJ...745....5K |s2cid=73598684}}</ref><ref name="SallumFollette2015">{{Cite journal|bibcode=2015Natur.527..342S|arxiv=1511.07456|title=Accreting protoplanets in the Lk ''Ca'' 15 transition disk|journal=Nature|volume=527|issue=7578|pages=342–4|last1=Sallum|first1=S.|last2=Follette|first2=K. B.|last3=Eisner|first3=J. A.|last4=Close|first4=L. M.|last5=Hinz|first5=P.|last6=Kratter|first6=K.|author6-link=Kaitlin Kratter|last7=Males|first7=J.|last8=Skemer|first8=A.|last9=MacIntosh|first9=B.|last10=Tuthill|first10=P.|last11=Bailey|first11=V.|last12=Defrère|first12=D.|last13=Morzinski|first13=K.|last14=Rodigas|first14=T.|last15=Spalding|first15=E.|last16=Vaz|first16=A.|last17=Weinberger|first17=A. J.|year=2015|doi=10.1038/nature15761|pmid=26581290|s2cid=916170}}</ref><ref>{{cite news |author=Irene Klotz |date=18 November 2015 |title=Astronomers see planet still growing in its stellar womb |url=http://newsdaily.com/2015/11/astronomers-see-planet-still-growing-in-its-stellar-womb/ |url-status=dead |archive-url=https://web.archive.org/web/20151119140655/http://newsdaily.com/2015/11/astronomers-see-planet-still-growing-in-its-stellar-womb/ |archive-date=19 November 2015 |access-date=20 November 2015 |publisher=News Daily |agency=Reuters}}</ref> Later, the existence of up to three planets was suspected. The planets' existence was refuted in 2019 as higher resolution imaging became available.<ref name=Currie2019>{{citation|arxiv=1905.04322|year=2019|title=No Clear, Direct Evidence for Multiple Protoplanets Orbiting Lk ''Ca'' 15: Lk ''Ca'' 15 BCD are Likely Inner Disk Signals|doi=10.3847/2041-8213/ab1b42 |last1=Currie |first1=Thayne |last2=Marois |first2=Christian |last3=Cieza |first3=Lucas |last4=Mulders |first4=Gijs D. |last5=Lawson |first5=Kellen |last6=Caceres |first6=Claudio |last7=Rodriguez-Ruiz |first7=Dary |last8=Wisniewski |first8=John |last9=Guyon |first9=Olivier |last10=Brandt |first10=Timothy D. |last11=Kasdin |first11=N. Jeremy |last12=Groff |first12=Tyler D. |last13=Lozi |first13=Julien |last14=Chilcote |first14=Jeffrey |last15=Hodapp |first15=Klaus |last16=Jovanovic |first16=Nemanja |last17=Martinache |first17=Frantz |last18=Skaf |first18=Nour |last19=Lyra |first19=Wladimir |last20=Tamura |first20=Motohide |last21=Asensio-Torres |first21=Ruben |last22=Dong |first22=Ruobing |last23=Grady |first23=Carol |last24=Gerard |first24=Benjamin |last25=Fukagawa |first25=Misato |last26=Hand |first26=Derek |last27=Hayashi |first27=Masahiko |last28=Henning |first28=Thomas |last29=Kudo |first29=Tomoyuki |last30=Kuzuhara |first30=Masayuki |journal=The Astrophysical Journal |volume=877 |issue=1 |pages=L3 |bibcode=2019ApJ...877L...3C |s2cid=152282903 |display-authors=1 |doi-access=free }}</ref>
{{OrbitboxPlanet begin | name = LkCa 15 | table_ref = |period_unit=day }} {{OrbitboxPlanet disk | disk = Protoplanetary disk component 1 | periapsis = 0.12 | apoapsis = 3<ref name=Currie2019/> | inclination = 50<ref name=Currie2019/> }} {{OrbitboxPlanet disk | disk = Protoplanetary disk component 2 | periapsis = 20 | apoapsis = 40<ref name=Currie2019/> | inclination = 51.5<ref name=Currie2019/> }} {{OrbitboxPlanet disk | disk = Protoplanetary disk component 3 | periapsis = 55 | apoapsis = 160<ref name=Currie2019/> | inclination = 50<ref name=Currie2019/> }} {{Orbitbox end}}
==References== {{Reflist|refs=
<ref name="Alencar">{{cite journal |last1=Alencar |first1=S. H. P. |last2=Bouvier |first2=J. |last3=Donati |first3=J.-F. |last4=Alecian |first4=E. |last5=Folsom |first5=C. P. |last6=Grankin |first6=K. |last7=Hussain |first7=G. A. J. |last8=Hill |first8=C. |last9=Cody |first9=A.-M. |last10=Carmona |first10=A. |last11=Dougados |first11=C. |last12=Gregory |first12=S. G. |last13=Herczeg |first13=G. |last14=Ménard |first14=F. |last15=Moutou |first15=C. |last16=Malo |first16=L. |last17=Takami |first17=M. |last18=collaboration |first18=MaTYSSE |title=Inner disk structure of the classical T Tauri star LkCa 15 |journal=Astronomy and Astrophysics |date=December 2018 |volume=620 |pages=A195 |doi=10.1051/0004-6361/201834263 |arxiv=1811.04806 |bibcode=2018A&A...620A.195A |doi-access=free }}</ref>
<ref name="AnA1993">{{cite journal |last1=Bouvier |first1=J. |last2=Cabrit |first2=S. |last3=Fernandez |first3=M. |last4=Martin |first4=E. L. |last5=Matthews |first5=J. M. |title=COYOTES I : the photometric variability and rotational evolution of T Tauri stars |journal=Astronomy and Astrophysics |date=May 1993 |volume=272 |pages=176-206 |bibcode=1993A&A...272..176B |url=https://articles.adsabs.harvard.edu/pdf/1993A%26A...272..176B |access-date=1 September 2025}}</ref>
<ref name="IBVS1995">{{cite journal |last1=Kazarovets |first1=E. V. |last2=Samus |first2=N. N. |title=The 72nd Name-List of Variable Stars |journal=Information Bulletin on Variable Stars |date=January 1995 |volume=4140 |pages=1-28 |url=https://articles.adsabs.harvard.edu/pdf/1995IBVS.4140....1K |access-date=1 September 2025 |bibcode=1995IBVS.4140....1K }}</ref>
}}
{{Stars of Taurus}}
Category:Pre-main-sequence stars Category:K-type main-sequence stars Category:T Tauri stars Tauri, V1079 F04363+2215 Category:Hypothetical planetary systems Category:Circumstellar disks Category:Taurus (constellation)