T Cephei

{{short description|Star in the constellation Cepheus}}

{{Starbox begin}}

{{Starbox image

| image=260px

| caption=Region of NGC 7023, T Cephei is marked with a green arrow

| credit=NASA, ESA and Digitized Sky Survey 2

}}

{{Starbox observe

| epoch=J2000

| ra={{RA|21|09|31.78348}}

| dec={{DEC|+68|29|27.2311}}

| appmag_v=5.2 - 11.3

| constell=Cepheus

}}

{{Starbox character

| type = AGB

| class=M6-9e{{cite journal|bibcode=1974ApJS...28..271K|title=Revised Catalog of Spectra of Mira Variables of Types ME and Se|journal=Astrophysical Journal Supplement|volume=28|pages=271|last1=Keenan|first1=Philip C.|last2=Garrison|first2=Robert F.|last3=Deutsch|first3=Armin J.|year=1974|doi=10.1086/190318|doi-access=free}}

| b-v=+1.49{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|last1=Ducati|first1=J. R.|year=2002}}

| u-b=+0.33

| variable=Mira{{cite journal|arxiv=1807.05144|doi=10.1051/0004-6361/201833317|title=Sulphur-bearing molecules in AGB stars|year=2018|last1=Danilovich|first1=T.|last2=Ramstedt|first2=S.|last3=Gobrecht|first3=D.|last4=Decin|first4=L.|last5=De Beck|first5=E.|last6=Olofsson|first6=H.|journal=Astronomy & Astrophysics|volume=617|pages=A132|s2cid=119225670}}

}}

{{Starbox astrometry

| radial_v=−8.03{{cite journal|bibcode=2005A&A...430..165F|title=Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters|journal=Astronomy and Astrophysics|volume=430|pages=165|last1=Famaey|first1=B.|last2=Jorissen|first2=A.|last3=Luri|first3=X.|last4=Mayor|first4=M.|last5=Udry|first5=S.|last6=Dejonghe|first6=H.|last7=Turon|first7=C.|year=2005|doi=10.1051/0004-6361:20041272|arxiv = astro-ph/0409579 |s2cid=17804304}}

| prop_mo_ra=−44.210

| prop_mo_dec=−44.921

| parallax=5.4400

| p_error=0.3476

| parallax_footnote={{cite Gaia DR3|2270451142963759744}}

| dist_pc=

| absmag_v=

}}

{{Starbox detail

| mass=0.55{{cite journal|doi=10.1086/170836|title=The mode of pulsation in Mira variables determined by the observed acceleration data|year=1991|last1=Tuchman|first1=Y.|journal=The Astrophysical Journal|volume=383|page=779|bibcode=1991ApJ...383..779T}}

| radius={{val|329|70|50}}{{cite book|series=Proc. SPIE |bibcode=2003SPIE.4838..181W|chapter=JHK-band spectro-interferometry of T Cep with the IOTA interferometer|volume=4838|pages=181–184|date=2003|doi=10.1117/12.458659|last1=Weigelt|first1=Gerd|title=Interferometry for Optical Astronomy II|last2=Beckmann|first2=Udo|last3=Berger|first3=Jean-Philippe|last4=Bloecker|first4=Thomas|last5=Brewer|first5=Michael K.|last6=Hofmann|first6=Karl-Heinz|last7=Lacasse|first7=Marc G.|last8=Malanushenko|first8=Victor|last9=Millan-Gabet|first9=Rafael|last10=Monnier|first10=John D.|last11=Ohnaka|first11=Keiichi|last12=Pedretti|first12=Ettore|last13=Schertl|first13=Dieter|last14=Schloerb|first14=F. Peter|last15=Scholz|first15=Michael|last16=Traub|first16=Wesley A.|last17=Yudin|first17=Boris|publisher=Society of Photo-optical Instrumentation Engineers (SPIE)|isbn=9780819446176|s2cid=123045204|url=https://resolver.caltech.edu/CaltechAUTHORS:20190115-111457389|editor1-first=Wesley A|editor1-last=Traub|display-authors=9}}

| luminosity=5,700{{cite journal|arxiv=1506.09065|bibcode=2015A&A...581A..60D|title=New observations and models of circumstellar CO line emission of AGB stars in the Herschel SUCCESS programme|journal=Astronomy & Astrophysics|volume=581|pages=A60|last1=Danilovich|first1=T.|last2=Teyssier|first2=D.|last3=Justtanont|first3=K.|last4=Olofsson|first4=H.|last5=Cerrigone|first5=L.|last6=Bujarrabal|first6=V.|last7=Alcolea|first7=J.|last8=Cernicharo|first8=J.|last9=Castro-Carrizo|first9=A.|last10=García-Lario|first10=P.|last11=Marston|first11=A.|year=2015|doi=10.1051/0004-6361/201526705|s2cid=55109956}}

| temperature=2,400 - 3,347{{cite journal |bibcode=2011ApJ...733...93G |title=A Temporal Study of the Oxygen-rich Pulsating Variable Asymptotic Giant Branch Star, T Cep: Investigation on Dust Formation and Dust Properties |last1=Guha Niyogi |first1=Suklima |last2=Speck |first2=Angela K. |last3=Onaka |first3=Takashi |journal=The Astrophysical Journal |year=2011 |volume=733 |issue=2 |page=93 |doi=10.1088/0004-637X/733/2/93 |arxiv=1103.5040 |s2cid=118332811 }}

| metal=

| rotation=

| age=

}}

{{Starbox catalog

| names= T Cephei, HR 8113, HD 202012, HIP 104451, BD+67°1291, GC 29611, SAO 19229, GSC 04460-02400

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{{Starbox reference

| Simbad = T+Cep

}}

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File:TCepLightCurve.png light curve of T Cephei, from AAVSO data]]

T Cephei is a Mira variable star in the constellation Cepheus. Located approximately {{convert|600|ly|pc|abbr=off}} distant, it varies between magnitudes 5.2 and 11.3 over a period of around 388 days.{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=8355 |title=T Cep|author=VSX|date=4 January 2010|work=AAVSO Website|publisher=American Association of Variable Star Observers|accessdate=1 July 2014}} When it is near its maximum brightness, it is faintly visible to the naked eye under good observing conditions.

Vitold Ceraski announced his discovery that the star is a variable star, in 1879. It appeared with its variable star designation, T Cephei, in Annie Jump Cannon's 1907 publication Second catalogue of variable stars. T Cephei is a red giant of spectral type M6-9e with an effective temperature 2,400 K, a radius of {{solar radius|329}}, a mass of {{solar mass|0.55}}, and a luminosity of {{solar luminosity|5,700}}. If it were in the place of the Sun, its photosphere would at least engulf the orbit of Mars. This star is believed to be in a late stage of its life, the asymptotic giant branch phase, blowing off its own atmosphere to form a white dwarf in a distant future.

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