16 Lacertae
{{Short description|Triple star system in the constellation Lacerta}}
{{Starbox begin
| name = 16 Lacertae
}}
{{Starbox image
| image = 250px
| caption = A light curve for EN Lacertae, plotted from TESS data
}}
{{Starbox observe
| epoch = J2000.0
| constell = Lacerta
| dec = {{DEC|+41|36|13.9482}}
| appmag_v = {{val|5.587|0.015}}
}}
{{Starbox character
| class = {{nowrap|B2 IV + F6–7 + F0}}
| b-v =
| u-b =
}}
{{Starbox astrometry
| radial_v = {{Val|−12.45|0.04}}
| parallax = 2.0692
| p_error = 0.0865
| absmag_v = {{Val|−2.67|0.14}}
}}
{{Starbox orbit
| period_unitless = 12.0969 d
| eccentricity = {{Val|0.0539|0.0026}}
| periastron = {{Val|61.4|2.1}}
| k1 = {{Val|23.85|0.05}}
}}
{{Starbox detail
| component1 = 16 Lac A
| mass = {{Val|9.5|0.03}}
| radius = {{Val|5.6|0.4}}
| luminosity = {{Val|7762|1151|1002|fmt=commas}}
| temperature = {{Val|23000|200|fmt=commas}}
| gravity = {{Val|3.95|0.05}}
| rotational_velocity = {{Val|12|1}}
| metal_fe = {{Val|0.00|0.08}}
| age_myr =
}}
{{Starbox catalog
| names = {{odlist | V=EN Lac | F=16 Lac | BD=+40°4949 | FK5= | HD=216916 | HIP=113281 | HR=8725 | SAO=52512 }}
}}
{{Starbox reference
| Simbad = *+16+Lac
}}
{{Starbox end}}
16 Lacertae is a triple star system in the northern constellation of Lacerta, located about 1,580 light years from the Sun. It has the variable star designation EN Lacertae; 16 Lacertae is the Flamsteed designation. This system is visible to the naked eye as a faint blue-white hued star with a maximum apparent visual magnitude of +5.587. It is moving closer to the Earth with a heliocentric radial velocity of –12 km/s.
The binary nature of the brighter component was discovered in 1910 by astronomer Oliver J. Lee at Yerkes Observatory. The first orbital elements were published by Otto Struve and Nicholay T. Bobrovnikov in 1925. This is a single-lined spectroscopic binary with an orbital period of 12.1 days and a small eccentricity of 0.05. It forms an eclipsing binary variable, although only the eclipse of the primary component has been detected. This component is a Beta Cephei variable star with three dominant pulsation modes having frequencies of around six per day. It has a stellar classification of B2 IV, matching a B-type subgiant star with 9.5 times the mass of the Sun and 5.6 times the Sun's radius.
The unseen secondary is an F-type star of class F6–7. The tertiary component is a magnitude 11.4 star with a class of F0. As of 2008, it was located at an angular separation of {{Val|27.6|ul=arcsecond}} from the primary.
References
{{reflist|refs=
{{cite simbad | title=16 Lac | access-date=2019-02-02 }}
{{cite DR2|1931240295282530688}}
| title=General Catalogue of Variable Stars
| display-authors=1 | last1=Samus | first1=N. N.
| last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V.
| last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.
| version=5.1 | journal=Astronomy Reports
| year=2017 | volume=61 | issue=1 | pages=80–88
| doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869 }}
| last=Lesh | first=Janet Rountree
| title=The Kinematics of the Gould Belt: an Expanding Group?
| journal=Astrophysical Journal Supplement
| volume=17 | page=371 | date=December 1968
| doi=10.1086/190179 | bibcode=1968ApJS...17..371L | doi-access=free }}
| title=Orbit of the spectroscopic binary 16 Lacertae
| last1=Struve | first1=O. | last2=Bobrovnikoff | first2=N. T.
| journal=Astrophysical Journal
| volume=62 | pages=139–143 | date=September 1925
| doi=10.1086/142919 | bibcode=1925ApJ....62..139S }}
| title=A new analysis of the radial velocity variations of the eclipsing and spectroscopic binary EN Lacertae
| display-authors=1 | last1=Lehmann | first1=H.
| last2=Harmanec | first2=P. | last3=Aerts | first3=C.
| last4=Božić | first4=H. | last5=Eenens | first5=P.
| last6=Hildebrandt | first6=G. | last7=Holmgren | first7=D.
| last8=Mathias | first8=P. | last9=Scholz | first9=G.
| last10=Šlechta | first10=M. | last11=Yang | first11=S.
| journal=Astronomy and Astrophysics
| volume=367 | pages=236–249 | date=February 2001
| doi=10.1051/0004-6361:20000344 | bibcode=2001A&A...367..236L | doi-access=free }}
| last1=Nieva | first1=M.-F. | last2=Przybilla | first2=N.
| title=Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
| journal=Astronomy & Astrophysics
| volume=539 | pages=A143 | year=2012
| bibcode=2012A&A...539A.143N | arxiv=1203.5787
| doi=10.1051/0004-6361/201118158 | s2cid=119206639 }}
| title=The 2003–2004 multisite photometric campaign for the β Cephei and eclipsing star 16 (EN) Lacertae with an appendix on 2 Andromedae, the variable comparison star
| last1=Jerzykiewicz | first1=M. | last2=Handler | first2=G.
| last3=Daszyńska-Daszkiewicz | first3=J. | last4=Pigulski | first4=A.
| last5=Poretti | first5=E. | last6=Rodríguez | first6=E.
| last7=Amado | first7=P. J. | last8=Kołaczkowski | first8=Z.
| last9=Uytterhoeven | first9=K. | last10=Dorokhova | first10=T. N.
| last11=Dorokhov | first11=N. I. | last12=Lorenz | first12=D.
| last13=Zsuffa | first13=D. | last14=Kim | first14=S.-L.
| last15=Bourge | first15=P.-O. | last16=Acke | first16=B.
| last17=De Ridder | first17=J. | last18=Verhoelst | first18=T.
| last19=Drummond | first19=R. | last20=Movchan | first20=A. I.
| last21=Lee | first21=J.-A. | last22=Stȩślicki | first22=M.
| last23=Molenda-Żakowicz | first23=J. | last24=Garrido | first24=R.
| last25=Kim | first25=S.-H. | last26=Michalska | first26=G.
| last27=Paparó | first27=M. | last28=Antoci | first28=V.
| last29=Aerts | first29=C. | display-authors=1
| journal=Monthly Notices of the Royal Astronomical Society
| volume=454 | issue=1 | pages=724–740 | year=2015
| arxiv=1508.05250 | bibcode=2015MNRAS.454..724J
| doi=10.1093/mnras/stv1958 | doi-access=free | s2cid=119220117 }}
| last1=Nieva | first1=María-Fernanda | last2=Przybilla | first2=Norbert
| title=Fundamental properties of nearby single early B-type stars
| journal=Astronomy & Astrophysics
| volume=566 | pages=A7 | year=2014
| doi=10.1051/0004-6361/201423373
| bibcode=2014A&A...566A...7N | arxiv=1412.1418 | s2cid=119227033 }}
| display-authors=1 | last1=Pourbaix | first1=D.
| last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H.
| last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I.
| last6=Levato | first6=H. | last7=Morrell | first7=N. I.
| last8=Torres | first8=G. | last9=Udry | first9=S.
| year=2004 | pages=727–732 | volume=424
| title=SB9: The Ninth Catalogue of Spectroscopic Binary Orbits
| journal=Astronomy & Astrophysics
| bibcode=2004A&A...424..727P | doi=10.1051/0004-6361:20041213 | arxiv=astro-ph/0406573 | s2cid=119387088 }}
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
| title=A catalogue of multiplicity among bright stellar systems
| journal=Monthly Notices of the Royal Astronomical Society
| volume=389 | issue=2 | pages=869–879 | date=September 2008
| doi=10.1111/j.1365-2966.2008.13596.x
| doi-access=free | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}
}}
{{Stars of Lacerta}}
{{DEFAULTSORT:16 Lacertae}}
Category:Beta Cephei variables
Category:Spectroscopic binaries