Theta Pyxidis

{{Short description|Star in the constellation Pyxis}}

{{Starbox begin}}

{{Starbox image

| image =

{{Location mark

| image=Pyxis IAU.svg

| float=center | width=250 | position=right

| mark=Red circle.svg | mark_width=10 | mark_link=θ Pyx

| x%=35.5 | y%=41.9

}}

| caption=Location of θ Pyxidis (circled)

}}

{{Starbox observe

| epoch = J2000

| ra = {{RA|09|21|29.60}}

| dec = {{DEC|–25|57|55.5}}

| appmag_v = 4.718{{citation | display-authors=1 | last1=Gutierrez-Moreno | first1=Adelina | last2=Moreno | first2=H. | last3=Stock | first3=J. | last4=Torres | first4=C. | last5=Wroblewski | first5=H. | title=A System of photometric standards | journal=Publications of the Department of Astronomy University of Chile | publisher=Publicaciones Universidad de Chile, Department de Astronomy | volume=1 | pages=1–17 | year=1966 | bibcode=1966PDAUC...1....1G | postscript=. }}

| constell = Pyxis

}}

{{Starbox character

| class = {{nowrap|M0.5 III Ba0.5}}{{cite journal|bibcode=1989ApJS...71..245K|title=The Perkins catalog of revised MK types for the cooler stars|journal=Astrophysical Journal Supplement Series|volume=71|pages=245|last1=Keenan|first1=Philip C.|last2=McNeil|first2=Raymond C.|year=1989|doi=10.1086/191373}}

| b-v = +1.651

| u-b = +1.984

| variable = semiregular variable{{cite journal | title=Long-term photometry and periods for 261 nearby pulsating M giants | last1=Tabur |first1 =V. |last2=Bedding |first2=T.R. |date=2009 |journal=Monthly Notices of the Royal Astronomical Society |volume= 400 | issue =4 |pages= 1945–61 |doi=10.1111/j.1365-2966.2009.15588.x | doi-access=free |arxiv = 0908.3228 |bibcode = 2009MNRAS.400.1945T | s2cid=15358380 }}

}}

{{Starbox astrometry

| radial_v = {{Val|+20.0|2.8}}{{citation | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}

| prop_mo_ra = –12.24 ± 0.40

| prop_mo_dec = –9.29 ± 0.37

| parallax = 6.49

| p_error = 0.45

| parallax_footnote = {{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}

| absmag_v = −1.22{{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=. }}

}}

{{Starbox detail

| mass =

| radius = 54

| luminosity = 970

| temperature = 3,825

| metal_fe =

| rotation =

| rotational_velocity =

| gravity =

| age =

}}

{{Starbox catalog

| names= {{odlist | B=θ Pyx, Theta Pyx | FK5=1243 | CPD=−25° 4152 | HD=80874 | HIP=45902 | HR=3718 | SAO=177322 | GC=12916 | PPM=256035 }}

}}

{{Starbox reference|Simbad=tet+Pyx}}

{{Starbox end}}

Theta Pyxidis, Latinized from θ Pyxidis, is a red M-type giant in the constellation Pyxis. It is approximately 500 ± 30 light years from Earth. It is of spectral type M1III and semi-regular variable with two measured periods of 13 and 98.3 days, and an average visual magnitude of 4.71, It shines with a luminosity approximately 970 times that of the Sun and has a surface temperature of 3825 K.{{cite journal|author=McDonald, I.|author2=Zijlstra, A. A.|author3=Boyer, M. L.|date=2012|title=Fundamental Parameters and Infrared Excesses of Hipparcos Stars|journal=Monthly Notices of the Royal Astronomical Society|volume=427|issue=1|pages=343–57|bibcode=2012MNRAS.427..343M|arxiv = 1208.2037 |doi = 10.1111/j.1365-2966.2012.21873.x |doi-access=free |s2cid=118665352}} It has a diameter around 54 times that of the Sun.{{cite journal|author=Pasinetti Fracassini, L. E.|author2=Pastori, L.|author3=Covino, S.|author4=Pozzi, A.|date=2001|title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics|journal=Astronomy & Astrophysics|volume=367|issue=2|pages=521–24|bibcode=2001A&A...367..521P|doi=10.1051/0004-6361:20000451|arxiv = astro-ph/0012289 |s2cid=425754}}

Theta Pyxidis is moving through the Galaxy at a speed of 22.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 21,200 and 24,700 light years from the center of the Galaxy. It came closest to the Sun 5.8 million years ago when it had brightened to magnitude 3.12 from a distance of 241 light years.{{citation needed|date=July 2017}}