UZ Pyxidis

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

{{Starbox begin

|name=UZ Pyxidis

}}

{{Starbox image

| image = 250px

| caption = A visual band light curve for UZ Pyxidis, plotted from ASAS data

}}

{{Starbox observe

|constell=Pyxis

|epoch=J2000

| ra = {{RA|08|46|36.3323}}

| dec = {{DEC|-29|43|41.203}}

| appmag_v= 6.99 - 7.63

}}

{{Starbox character

|class=C5₅J (R8){{cite web|url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=27220|title=VSX: Detail for UZ Pyx|author=Otero, Sebastian Alberto|date=15 April 2012|work=The International Variable Star Index|publisher=American Association of Variable Star Observers|access-date=18 January 2017}}

|b-v=+2.01{{cite journal|bibcode=2003A&A...397..997P|arxiv=astro-ph/0211048|title=Hipparcos red stars in the HpVT2 and VIC systems|journal=Astronomy and Astrophysics|volume=397|issue=3|pages=997–1010|last1=Platais|first1=I.|last2=Pourbaix|first2=D.|last3=Jorissen|first3=A.|last4=Makarov|first4=V. V.|last5=Berdnikov|first5=L. N.|last6=Samus|first6=N. N.|last7=Lloyd Evans|first7=T.|last8=Lebzelter|first8=T.|last9=Sperauskas|first9=J.|year=2003|doi=10.1051/0004-6361:20021589|s2cid=17382277}}

|u-b=+2.99

|variable=SRb{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

}}

{{Starbox astrometry

|radial_v=13.00{{cite journal|title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system|author=Gontcharov, G. A.|date=2006|journal=Astronomy Letters|volume=32|issue=11|pages=759–771|bibcode=2006AstL...32..759G|doi=10.1134/S1063773706110065|arxiv=1606.08053|s2cid=119231169}}

|prop_mo_ra=−5.767

|prop_mo_dec=1.674

|parallax=0.8949

|p_error=0.0183

|parallax_footnote={{cite Gaia EDR3|5642141242177662080}}

|absmag_v=−1.2{{cite journal |doi=10.1134/S1063773711090040 |title=The red giant branch in the Tycho-2 catalogue |year=2011 |last1=Gontcharov |first1=G. A. |journal=Astronomy Letters |volume=37 |issue=10 |pages=707–717 |arxiv=1607.00557 |bibcode=2011AstL...37..707G |s2cid=119272127 }}

}}

{{Starbox detail

|source=

|mass=2.1

|temperature=3,325{{cite journal|author1=Bergeat, J.|author2=Chevallier, L.|date=2005|title=The mass loss of C-rich giants|journal=Astronomy and Astrophysics|volume=429|pages=235–246|bibcode=2005A&A...429..235B|arxiv=astro-ph/0601366|doi=10.1051/0004-6361:20041280|s2cid=56424665}}

|luminosity=5,649

|radius=221{{Cite journal|display-authors=1|last1=Stassun|first1=Keivan G.|last2=Oelkers|first2=Ryan J.|last3=Paegert|first3=Martin|last4=Torres|first4=Guillermo|last5=Pepper|first5=Joshua|last6=De Lee|first6=Nathan|last7=Collins|first7=Kevin|last8=Latham|first8=David W.|last9=Muirhead|first9=Philip S.|last10=Chittidi|first10=Jay|last11=Rojas-Ayala|first11=Bárbara|date=2019-10-01|title=The Revised TESS Input Catalog and Candidate Target List|bibcode=2019AJ....158..138S|journal=The Astronomical Journal|volume=158|issue=4|pages=138|doi=10.3847/1538-3881/ab3467|arxiv=1905.10694 |hdl=1721.1/124721|s2cid=166227927|issn=0004-6256|hdl-access=free |doi-access=free }}

|gravity=−0.236{{cite journal |bibcode=2022yCat.1354....0A |title=VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022) |last1=Anders |first1=F. |last2=Khalatyan |first2=A. |last3=Queiroz |first3=A. B. A. |last4=Chiappini |first4=C. |last5=Ardevol |first5=J. |last6=Casamiquela |first6=L. |last7=Figueras |first7=F. |last8=Jimenez-Arranz |first8=O. |last9=Jordi |first9=C. |last10=Monguio |first10=M. |last11=Romero-Gomez |first11=M. |last12=Altamirano |first12=D. |last13=Antoja |first13=T. |last14=Assaad |first14=R. |last15=Cantat-Gaudin |first15=T. |last16=Castro-Ginard |first16=A. |last17=Enke |first17=H. |last18=Girardi |first18=L. |last19=Guiglion |first19=G. |last20=Khan |first20=S. |last21=Luri |first21=X. |last22=Miglio |first22=A. |last23=Minchev |first23=I. |last24=Ramos |first24=P. |last25=Santiago |first25=B. X. |last26=Steinmetz |first26=M. |journal=Vizier Online Data Catalog |year=2022 }}

|metal_fe=−0.32

}}

{{Starbox catalog

|names=UZ Pyx, CD-29°6735, HD 75021, HIP 43093, SAO 176458, GC 12117

}}

{{Starbox reference

|Simbad=HD+75021

}}

{{Starbox end}}

UZ Pyxidis (HD 75021) is a semiregular variable star in the constellation Pyxis. It is located about 3,600 light-years (1,100 parsecs) away from the Earth.

UZ Pyxidis lies directly between α and γ Pyxidis. It has a common proper motion companion, HD 75022, less than 2' away but the two are not listed in double star catalogues.

UZ Pyxidis is a carbon star. These types of stars are known for having large amounts of carbon in their atmospheres, forming carbon compounds that make the star appear strikingly red. It was first recognised as having an unusual spectrum in 1893.{{cite journal|bibcode=1893AstAp..12..546F |title=Stars having peculiar spectra |journal=Astronomy and Astro-Physics |volume=12 |pages=546 |last1=Fleming |first1=W. P. |year=1893 }} Under the Morgan–Keenan classification of carbon stars, UZ Pyxidis' spectral type is C5₅; if it were a normal giant star, this would correspond to a spectral type of about K5.{{cite journal|author1=Keenan, P. C.|author2=Morgan, W. W.|date=1941|title=The Classification of the Red Carbon Stars|journal=The Astrophysical Journal|volume=94|page=501|bibcode=1941ApJ....94..501K|doi=10.1086/144356}} It is also unusual in that it has very strong isotopic bands of C₂ and CN.{{cite journal|author1=Keenan, P. C.|date=1993|title=Revised MK Spectral Classification of the Red Carbon Stars|volume=105|page=905|journal=Publications of the Astronomical Society of the Pacific|bibcode=1993PASP..105..905K|doi=10.1086/133252|doi-access=free}}

There were hints that the star is variable as early as the late 19th century, and its variability was firmly estabilished by Olin J. Eggen in 1972.{{cite journal|bibcode=1972ApJ...177..489E|title=The classification of intrinsic variable stars. II. The red variables of S and related types|journal=Astrophysical Journal|volume=177|pages=489|last1=Eggen|first1=O. J.|year=1972|doi=10.1086/151725|doi-access=free}}{{cite journal|bibcode=1972ApJ...174...45E|title=The classification of intrinsic variable stars. I. The red variables of type N|journal=Astrophysical Journal|volume=174|pages=45|last1=Eggen|first1=O. J.|year=1972|doi=10.1086/151467}} The variable star designation UZ Pyxidis was assigned in 1978.{{cite journal|bibcode=1978IBVS.1414....1K|title=63rd Name-List of Variable Stars|journal=Information Bulletin on Variable Stars|volume=1414|pages=1|last1=Kholopov|first1=P. N.|last2=Kukarkina|first2=N. P.|last3=Perova|first3=N. B.|year=1978}} UZ Pyxidis is classified as a semiregular variable with a dominant period of 159.6 days. It varies in brightness between magnitude 6.99 and 7.63.