Alpha Lacertae

{{Starbox begin

| name = α Lacertae

}}

{{Starbox image

| image = 250px

| caption = α Lacertae in optical light

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| constell = Lacerta

| ra = {{RA|22|31|17.50131}}

| dec = {{DEC|+50|16|56.9682}}

| appmag_v = 3.76

}}

{{Starbox character

| class = A1 V

| u-b = 0.00

| b-v = {{Val|0.031|0.003}}

| r-i = −0.03

}}

{{Starbox astrometry

| radial_v = {{Val|−4.5|0.9}}

| prop_mo_ra = 137.51

| prop_mo_dec = 17.01

| parallax = 31.79

| p_error = 0.12

| parallax_footnote =

| absmag_v = 1.27

}}

{{Starbox detail

| source =

| mass = 2.194

| radius = {{val|2.1432|0.0737}}

| luminosity = {{val|27.6750|0.2138}}

| temperature = {{val|9050|157|fmt=commas}}

| gravity = {{Val|4.27|0.14}}

| rotational_velocity = 128

| age_myr = 400

}}

{{Starbox catalog

| names={{odlist | name=Stellio | B=α Lac | F=7 Lac | ADS=16021 A | BD=+49°3875 | CCDM=J22313+5017A | FK5=848 | GC=31471 | HD=213558 | HIP=111169 | HR=8585 | SAO=34542 | WDS=J22139+3943 }}

}}

{{Starbox reference

| Simbad=alf+lac

}}

Alpha Lacertae, Latinised from α Lacertae, also named Stellio, is a single white-hued star in the constellation of Lacerta, located 103 light-years from the Sun. It is the brightest star in Lacerta with an apparent visual magnitude of 3.76. The star is moving closer to the Earth with a heliocentric radial velocity of −4.5 km/s.

This is an ordinary A-type main-sequence star with a stellar classification of A1 V, which indicates it is generating energy through hydrogen fusion at its core. It is around 400 million years old with a relatively high rate of spin, showing a projected rotational velocity of 128 km/s. The star has 2.2 times the mass of the Sun and 2.1 times the Sun's radius. It is radiating 28 times the Sun's luminosity from its photosphere at an effective temperature of {{val|9050|ul=K|fmt=commas}}.

Alpha Lacertae has a visual companion, CCDM J22313+5017B, of spectral type A and apparent visual magnitude 11.8, approximately 36 arcseconds away. The companion is optical, a chance line-of-sight coincidence.

Naming

Alpha Lacertae is the Bayer designation for this star; it has the Flamsteed designation 7 Lacertae. In Chinese, {{lang|zh|螣蛇}} ({{lang|zh-Latn|Téng Shé}}), meaning Flying Serpent, refers to an asterism consisting of α Lacertae, 4 Lacertae, π² Cygni, π¹ Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, the Chinese name for α Lacertae itself is {{lang|zh|螣蛇一}} ({{lang|zh-Latn|Téng Shé yī}}, {{langx|en|the First Star of Flying Serpent}}).{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060707.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日] {{Webarchive|url=https://web.archive.org/web/20110521232711/http://aeea.nmns.edu.tw/2006/0607/ap060707.html |date=2011-05-21 }}

The IAU Working Group on Star Names approved the name Stellio for this star on 29 August 2024 and it is now so entered in the IAU Catalog of Star Names. Stellio is an obsolete historical name for the constellation Lacerta, named after the lizard Laudakia stellio, the starred agama or stellion.

References

{{Reflist|refs=

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{{citation | display-authors=1

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| title=A study of the bright A stars. I. A catalogue of spectral classifications

| journal=Astronomical Journal | postscript=.

| volume=74 | pages=375–406 | date=April 1969

| doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}

{{citation

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| bibcode=2007A&A...474..653V | arxiv=0708.1752

| doi=10.1051/0004-6361:20078357 | s2cid=18759600

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{{citation

| title=XHIP: An extended hipparcos compilation

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

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| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015

| s2cid=119257644 | postscript=. }}

[http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=8585 HR 8585], database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID [http://vizier.u-strasbg.fr/viz-bin/Cat?V/50 V/50]. Accessed on line September 3, 2008.

Entry 22313+5017, discoverer code BU 703,

[http://ad.usno.navy.mil/wds/wdsnewframe4.html The Washington Double Star Catalog] {{webarchive |url=https://web.archive.org/web/20080908010456/http://ad.usno.navy.mil/wds/wdsnewframe4.html |date=September 8, 2008 }},

United States Naval Observatory. Accessed on line September 3, 2008.

{{citation

| display-authors=1

| last1=Boyajian | first1=Tabetha S. | last2=von Braun | first2=Kaspar

| last3=van Belle | first3=Gerard | last4=Farrington | first4=Chris

| last5=Schaefer | first5=Gail | last6=Jones | first6=Jeremy

| last7=White | first7=Russel | last8=McAlister | first8=Harold A.

| last9=ten Brummelaar | first9=Theo A. | last10=Ridgway | first10=Stephen

| last11=Gies | first11=Douglas | last12=Sturmann | first12=Laszlo

| last13=Sturmann | first13=Judit | last14=Turner | first14=Nils H.

| last15=Goldfinger | first15=P. J. | last16=Vargas | first16=Norm

| title=Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations

| journal=The Astrophysical Journal | volume=771

| issue=1 | id=40 | pages=31 | date=July 2013

| arxiv=1306.2974 | doi=10.1088/0004-637X/771/1/40

| bibcode=2013ApJ...771...40B | s2cid=14911430 | postscript=.

}} See Table 3.

{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=22 February 2025}}

{{cite web |last=Ridpath |first=Ian |author-link=Ian Ridpath |title=Star Tales - Lacerta |url=http://www.ianridpath.com/startales/lacerta.html |access-date=6 May 2025}}

}}

External links

{{citation

| first1=James B. | last1=Kaler | work=STARS

| title=Alpha Lac | publisher=University of Illinois

| url=http://stars.astro.illinois.edu/sow/alphalac.html

| accessdate=2019-02-04 | postscript=. }}

Category:A-type main-sequence stars

Category:Double stars