T Vulpeculae

{{Short description|Variable star in the constellation Vulpecula}}

{{Starbox begin

| name = T Vulpeculae

}}

{{Starbox image

| image = 250px

| caption = A visual band light curve for T Vulpeculae, adapted from Kiss (1998)

}}

{{Starbox observe

| epoch = J2000

| constell = Vulpecula

| ra = {{RA|20|51|28.23825}}

| dec = {{DEC|+28|15|01.8166}}

| appmag_v = 5.754 {{nowrap|(5.41 – 6.09)}}

}}

{{Starbox character

| type =

| class = {{nowrap|F5 Ib + A0.8 V}}

| b-v = {{Val|+0.616|0.049}}

| u-b =

| variable = δ Cep

}}

{{Starbox astrometry

| radial_v = {{Val|−2.6|0.6}}

| prop_mo_ra = +3.496

| prop_mo_dec = −15.087

| parallax = 1.6738

| p_error = 0.0891

| parallax_footnote =

| absmag_v = −3.19

}}

{{Starbox detail

| source =

| component1 = T Vul A

| mass = 4.9

| radius = {{Val|35.6|4.4}}

| luminosity = 1,620

| gravity = 1.75

| temperature = 6,220

| metal_fe = 0.01

| rotational_velocity =

| age_myr = 120

| component2 = T Vul B

| mass2 = 2.1

}}

{{Starbox catalog

| names={{odlist | V=T Vul | BD=+27° 3890 | FK5= | HD=198726 | HIP=102949 | HR=7988 | SAO=89216 | AAVSO=2047+27 }}

}}

{{Starbox reference

| Simbad = HD+198726

}}

T Vulpeculae is a possible binary star system in the northern constellation of Vulpecula, near the star Zeta Cygni, close to the pair 31 Vulpeculae and 32 Vulpeculae. It is visible to the naked eye with an apparent visual magnitude that ranges around 5.75. The distance to this system is around 1,900 light years, as determined from its annual parallax shift of {{Val|1.67|ul=mas}}.

A well-studied Classical Cepheid variable and one of the brightest known, the apparent magnitude of T Vulpeculae ranges from 5.41 to 6.09 over a period of 4.435 days. It is a yellow-white hued supergiant of spectral type F5 Ib. The variability of T Vul was discovered in 1885 by Edwin Sawyer. Observations between 1885 and 2003 shows a small but continuous decrease in the period of variability amounting to 0.25 seconds per year.

The companion star was detected in 1992; it is an A-type main-sequence star with a class of A0.8 V and 2.1 times the Sun's mass. Orbital periods of 738 and 1,745 days have been proposed for the pair, although, as of 2015, there remains doubt as to whether this is an actual binary system.

References

{{reflist|refs=

{{cite journal |last1=Kiss |first1=Laszlo L. |title=A photometric and spectroscopic study of the brightest northern Cepheids - I. Observations |journal=Monthly Notices of the Royal Astronomical Society |date=July 1998 |volume=297 |issue=3 |page=825 |doi=10.1046/j.1365-8711.1998.01559.x |bibcode=1998MNRAS.297..825K |doi-access=free }}

{{citation

| title=XHIP: An extended hipparcos compilation

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

| journal=Astronomy Letters

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

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

| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

{{cite journal

| title=On a new variable star in the Constellation Vulpecula

| last1=Sawyer | first1=E. F. | journal=Astronomische Nachrichten

| volume=113 | issue=16 | page=265 | year=1886

| bibcode=1886AN....113..265S | doi=10.1002/asna.18861131608 | url=https://zenodo.org/record/1424725 }}

{{cite web

| title=T Vulpeculae |date=4 January 2010

| last=BSJ | work=AAVSO Website

| publisher=American Association of Variable Star Observers

| url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=38178

| accessdate=24 January 2014 }}

{{cite journal | display-authors=4

| last1=Evans | first1=Nancy Remage | last2=Bond | first2=Howard E.

| last3=Schaefer | first3=Gail H. | last4=Mason | first4=Brian D.

| last5=Karovska | first5=Margarita | last6=Tingle | first6=Evan

| title=Binary Cepheids: Separations and Mass Ratios in 5M ⊙ Binaries

| journal=Astronomical Journal

| volume=146 | issue=4 | pages=93, 10 | date=2013

| arxiv=1307.7123v1 | doi=10.1088/0004-6256/146/4/93

| bibcode = 2013AJ....146...93E | s2cid=34133110 }}

{{cite journal

| title=Robust high-contrast companion detection from interferometric observations. The CANDID algorithm and an application to six binary Cepheids

| last1=Gallenne | first1=A. | last2=Mérand | first2=A.

| last3=Kervella | first3=P. | last4=Monnier | first4=J. D.

| last5=Schaefer | first5=G. H. | last6=Baron | first6=F.

| last7=Breitfelder | first7=J. | last8=Le Bouquin | first8=J. B.

| last9=Roettenbacher | first9=R. M. | last10=Gieren | first10=W.

| last11=Pietrzyński | first11=G. | last12=McAlister | first12=H.

| last13=ten Brummelaar | first13=T. | last14=Sturmann | first14=J.

| last15=Sturmann | first15=L. | last16=Turner | first16=N.

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| journal=Astronomy & Astrophysics | display-authors=1

| volume=579 | id=A68 | pages=12 | date=July 2015

| doi=10.1051/0004-6361/201525917 | arxiv=1505.02715 | bibcode=2015A&A...579A..68G | doi-access=free }}

{{cite journal

| title=Properties of the population of classical Cepheids in the Galaxy

| last3=Kovtyukh | first3=V. V. | last4=Mishenina | first4=T. V.

| volume=39 | issue=12 | pages=851 | year=2013

| bibcode=2013AstL...39..851M | doi=10.1134/S1063773713120050 | s2cid=119788977 }}

{{cite journal

| title=Mean angular diameters, distances, and pulsation modes of the classical Cepheids FF Aquilae and T Vulpeculae. CHARA/FLUOR near-infrared interferometric observations

| display-authors=1 | last1=Gallenne | first1=A.

| last2=Kervella | first2=P. | last3=Mérand | first3=A.

| last4=McAlister | first4=H. | last5=ten Brummelaar | first5=T.

| last6=Coudé du Foresto | first6=V. | last7=Sturmann | first7=J.

| last8=Sturmann | first8=L. | last9=Turner | first9=N.

| last10=Farrington | first10=C. | last11=Goldfinger | first11=P. J.

| journal=Astronomy & Astrophysics | arxiv=1203.6682

| volume=541 | id=A87 | pages=5 | date=May 2012

| doi=10.1051/0004-6361/201219102 | bibcode=2012A&A...541A..87G | s2cid=2424989 }}

{{cite journal

| title=T Vulpeculae: Maximum Times Covering 120 Years Show a Slight, Continuous Period Decrease

| last1=Meyer | first1=Ralf

| journal=Open European Journal on Variable Stars

| volume=46 | page=1 | date=August 2006

| bibcode=2006OEJV...46....1M }}

{{cite journal

| title=The luminosity of the classical Cepheid T VUL

| last1=Evans | first1=Nancy R.

| journal=Astronomical Journal

| volume=104 | issue=1 | date=July 1992 | pages=216–219

| doi=10.1086/116232 | bibcode=1992AJ....104..216E }}

{{cite journal

| title=Binary Properties from Cepheid Radial Velocities (CRaV)

| display-authors=1 | last1=Evans | first1=Nancy Remage

| last2=Berdnikov | first2=Leonid | last3=Lauer | first3=Jennifer

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| journal=The Astronomical Journal

| doi=10.1088/0004-6256/150/1/13 | bibcode=2015AJ....150...13E

| arxiv=1505.05823 | s2cid=54943097 }}

{{cite journal

| display-authors=1 | last1=Gray | first1=R. O.

| last2=Graham | first2=P. W. | last3=Hoyt | first3=S. R.

| title=The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. II. Basic Parameters of Program Stars and the Role of Microturbulence

| journal=The Astronomical Journal

| volume=121 | issue=4 | pages=2159 | year=2001

| bibcode=2001AJ....121.2159G | doi=10.1086/319957 | doi-access=free }}

{{citation

| title=Exploring the Night Sky with Binoculars

| first1=Patrick | last1=Moore

| publisher=Cambridge University Press

| year=2000 | isbn=978-0521793902 | page=147

| url=https://books.google.com/books?id=Jvbtl2Vyxm4C&pg=PA147 }}

}}

Category:Classical Cepheid variables

Category:F-type supergiants