Pi Piscis Austrini
{{Short description|Star in the constellation Piscis Austrinus}}
{{Starbox begin}}
{{Starbox image
| image =
{{Location mark
|image=Piscis_Austrinus_IAU.svg|alt=|float=center|width=280
|label=|position=right
|mark=Red circle.svg|mark_width=12|mark_link=π PsA
|x%=26.4|y%=60.5
}}
| caption = Location of π Piscis Austrini (circled)
}}
{{Starbox observe
| constell = Piscis Austrinus
| epoch = J2000
| dec = {{DEC|−34|44|57.8827}}
}}
{{Starbox character
| type =
| class = {{nowrap|F1 V Fe-0.8}} + F3 V
| variable =
}}
{{Starbox astrometry
| parallax = 35.3691
| p_error = 0.2124
}}
{{Starbox orbit
| period_unitless = {{Val|178.3177|0.0038|u=days}}
| axis_unitless = ≥ {{Convert|44.3e6|km|AU|disp=out|lk=on}}
| periastron = {{Val|2435319.73|0.25|fmt=commas}}
| eccentricity = {{Val|0.5286|0.0041}}
| periarg = {{Val|2.62|0.81}}
| k1 = {{Val|21.28|0.16}}
}}
{{Starbox detail
| component1 = A
| radius = {{Val|1.64|0.11|0.08}}
| luminosity = {{Val|5.85|0.04}}
| temperature = {{Val|7003|195|216|fmt=commas}}
| rotational_velocity =
}}
{{Starbox catalog
| names = {{odlist | B=π PsA | CD=−35°15630 | GJ=886.2 | GJ2=9807 | HD=217792 | HIP=113860 | HR=8767 | SAO=214275 | GC=32122 }}
}}
{{Starbox reference
| Simbad = pi+PsA
}}
{{Starbox end}}
Pi Piscis Austrini, Latinized from π Piscis Austrini, is binary star system in the southern constellation of Piscis Austrinus, near the eastern constellation border with Sculptor. It has a yellow-white hue and is visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.12. The system is located at a distance of 92 light-years from the Sun based on parallax. Its radial velocity is poorly constrained, but it appears to be drifting closer at a rate of around −6 km/s. Pi Piscis Austrini is moving through the galaxy at a velocity of 16.3 km/s relative to the Sun. Its projected galactic orbit carries it between 24,000 and 37,500 light-years from the center of the galaxy.
This is a single-lined spectroscopic binary system with an orbital period of 178.3 days and an eccentricity of 0.53. The primary component is an F-type main-sequence star with a stellar classification of {{nowrap|F1 V Fe-0.8}}.
File:PiPsALightCurve.png for Pi Piscis Austrini, plotted from Hipparcos data]]
As of 2023, there appears to be no consensus in the astronomical literature about whether or not Pi Piscis Austrini is a variable star, and if it is variable, what type of variable star it is. In 1965 it was designated a classical Cepheid variable star with a visual (V) band brightness that varied by 0.3 magnitudes over a period of 7.975 days. The AAVSO's International Variable Star index lists it as a Gamma Doradus variable, with a V band magnitude range of 5.10 to 5.12. Axel Thomas, writing in the AAVSO's Journal, reports that the star appears to be a semiregular variable star, varying by 0.7 magnitudes in V band over a period of 8.625 days. Koen and Eyer examined the Hipparcos data for the star, and report it to be a microvariable with a period of 1.06039 days. On the other hand, the General Catalog of Variable Stars reports the star's brightness as constant, and in separate studies Michel Petit and E. Janot-Pacheco could not detect any change in brightness.
Pi Piscis Austrini displays an infrared excess, suggesting a circumstellar disk is orbiting at a radius of {{Val|23|u=AU}} with a mean temperature of 90 K. The cooler secondary companion has a class of F3 V. The system appears to be a source of X-ray emission.
References
{{reflist|refs=
{{cite simbad|title=* pi. PsA|accessdate=7 January 2017}}
{{cite DR2|6554537293934842496}}
| title=pi PsA | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=26602
| website=The International Variable Star Index | publisher=AAVSO
| access-date=1 January 2023}}
| url=https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats
| website=Centre de Données astronomiques de Strasbourg | title=/ftp/cats/more/HIP/cdroms/cats
| publisher=Strasbourg astronomical Data Center | access-date=15 October 2022}}
| title=pi. PsA | url=http://www.sai.msu.su/gcvs/cgi-bin/search2.cgi?search=pi.+PsA
| website=General Catalog of Variable Stars
| publisher=Sternberg Astronomical Institute, Moscow University | access-date=1 January 2023}}
| last1=Petit | first1=Michel | title=Pi PsA | bibcode=1972IBVS..695....2P
| journal=Information Bulletin on Variable Stars |date=July 1972 |volume=695 |issue=2
| page=2 | url=https://ibvs.konkoly.hu/pub/ibvs/0601/0695.pdf | access-date=1 January 2023}}
| last1=Thomas | first1=Axel | title=Π PsA - Who Are You?
| journal=The Journal of the American Association of Variable Star Observers
| date=June 1991 | volume=20 | issue=1 | pages=23–24 | bibcode=1991JAVSO..20...23T
| url=https://articles.adsabs.harvard.edu/pdf/1991JAVSO..20...23T | access-date=1 January 2023}}
| last1=Koen | first1=Chris | last2=Eyer | first2=Laurent
| title=New periodic variables from the Hipparcos epoch photometry
| journal=Monthly Notices of the Royal Astronomical Society
| date=March 2002 | volume=331 | issue=1 | pages=45–59
| doi=10.1046/j.1365-8711.2002.05150.x | doi-access=free | arxiv=astro-ph/0112194 | bibcode=2002MNRAS.331...45K
| s2cid=10505995 }}
| title=A Comprehensive Census of Nearby Infrared Excess Stars
| last1=Cotten | first1=Tara H. | last2=Song | first2=Inseok
| journal=The Astrophysical Journal Supplement Series
| volume=225 | issue=1 | id=15 | pages=24 | date=July 2016
| bibcode=2016ApJS..225...15C | arxiv=1606.01134
| doi=10.3847/0067-0049/225/1/15 | s2cid=118438871 | doi-access=free }}
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
| title=A catalogue of multiplicity among bright stellar systems
| journal=Monthly Notices of the Royal Astronomical Society
| volume=389 | issue=2 | pages=869–879 | date=September 2008
| bibcode=2008MNRAS.389..869E | arxiv=0806.2878
| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | s2cid=14878976 }}
| title=On the cepheid nature of pi PsA
| last=Janot-Pacheco | first=E.
| journal=Astronomy and Astrophysics
| volume=34 | pages=325–326 | date=August 1974
| bibcode=1974A&A....34..325J }}
| last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V.
| last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N.
| last5=Pastukhova | first5=E. N. | display-authors=1
| title=General Catalogue of Variable Stars
| version=GCVS 5.1 | journal=Astronomy Reports
| year=2017 | volume=61 | issue=1 | pages=80–88
| doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869 | postscript=. }}
| last1=Gray | first1=R. O. | last2=Corbally | first2=C. J.
| last3=Garrison | first3=R. F. | last4=McFadden | first4=M. T.
| last5=Bubar | first5=E. J. | last6=McGahee | first6=C. E.
| last7=O'Donoghue | first7=A. A. | last8=Knox | first8=E. R.
| title=Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample
| display-authors=1 | journal=The Astronomical Journal
| volume=132 | issue=1 | pages=161–170 | date=July 2006
| doi=10.1086/504637 | bibcode=2006AJ....132..161G
| arxiv=astro-ph/0603770 | s2cid=119476992 }}
| title=Orbital elements of six spectroscopic binary stars
| last1=Bopp | first1=B. W. | last2=Evans | first2=D. S.
| last3=Laing | first3=J. D. | last4=Deeming | first4=T. J.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=147 | pages=355–366 | date=1970 | issue=4 | display-authors=1
| doi=10.1093/mnras/147.4.355 | bibcode=1970MNRAS.147..355B | doi-access=free }}
| last1=Haakonsen | first1=Christian Bernt | last2=Rutledge | first2=Robert E.
| title=XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources
| journal=The Astrophysical Journal Supplement
| volume=184 | issue=1 | pages=138–151 | date=September 2009
| doi=10.1088/0067-0049/184/1/138 | bibcode=2009ApJS..184..138H
| arxiv=0910.3229 | s2cid=119267456 }}
| title=UBV Photometry of Some Southern Stars (Second List)
| journal=Monthly Notes of the Astron. Soc. Southern Africa
| volume=32 | page=11 | date=1973
| bibcode=1973MNSSA..32...11C | last1=Cousins
| first1=A. W. J.
}}
| 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 | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
}}
External links
- {{cite web
| first=James B. | last=Kaler | date=December 12, 2009
| title=Pi Piscis Austrini | work=STARS
| url=http://stars.astro.illinois.edu/sow/pipsa.html }}
{{Stars of Piscis Austrinus}}
{{DEFAULTSORT:Pi Piscis Austrini}}
Category:F-type main-sequence stars
Category:Spectroscopic binaries