Astronomy:Pi Piscis Austrini

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Short description: Star in the constellation Piscis Austrinus
Pi Piscis Austrini
Piscis Austrinus IAU.svg
Red circle.svg
Location of π Piscis Austrini (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Piscis Austrinus
Right ascension  23h 03m 29.81653s[1]
Declination −34° 44′ 57.8827″[1]
Apparent magnitude (V) 5.12[2]
Characteristics
Spectral type F1 V Fe-0.8[3] + F3 V[4][5]
U−B color index +0.00[6]
B−V color index +0.29[6]
Astrometry
Radial velocity (Rv)−6.0±4.2[2] km/s
Proper motion (μ) RA: +72.789[1] mas/yr
Dec.: +83.569[1] mas/yr
Parallax (π)35.3691 ± 0.2124[1] mas
Distance92.2 ± 0.6 ly
(28.3 ± 0.2 pc)
Absolute magnitude (MV)+2.78[2]
Orbit[7]
Period (P)178.3177±0.0038 d
Semi-major axis (a)≥ 0.296 astronomical unit|AU
Eccentricity (e)0.5286±0.0041
Periastron epoch (T)2,435,319.73±0.25
Argument of periastron (ω)
(secondary)		2.62±0.81°
Semi-amplitude (K1)
(primary)		21.28±0.16 km/s
Details
A
Mass1.51[3] M☉
Radius1.64+0.11
−0.08[1] R☉
Luminosity5.85±0.04[1] L☉
Surface gravity (log g)4.30±0.14[3] cgs
Temperature7,003+195
−216[1] K
Metallicity [Fe/H]+0.12[2] dex
Age474[3] Myr
Other designations
π PsA, CD−35° 15630, GC 32122, GJ 886.2, (Wo) 9807, HD 217792, HIP 113860, HR 8767, SAO 214275[8]
Database references
SIMBADdata

Pi Piscis Austrini, Latinized from π Piscis Austrini, is binary star[5] 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.[2] The system is located at a distance of 92 light-years from the Sun based on parallax.[1] Its radial velocity is poorly constrained, but it appears to be drifting closer at a rate of around −6 km/s.[2] 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.[2]

This is a single-lined spectroscopic binary system with an orbital period of 178.3 days and an eccentricity of 0.53.[7] The primary component is an F-type main-sequence star with a stellar classification of F1 V Fe-0.8.[3]

A light curve for Pi Piscis Austrini, plotted from Hipparcos data[9]

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.[10] 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.[11] 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.[12] Koen and Eyer examined the Hipparcos data for the star, and report it to be a microvariable with a period of 1.06039 days.[13] On the other hand, the General Catalog of Variable Stars reports the star's brightness as constant,[14] and in separate studies Michel Petit[15] and E. Janot-Pacheco could not detect any change in brightness.[10]

Pi Piscis Austrini displays an infrared excess, suggesting a circumstellar disk is orbiting at a radius of 23 AU with a mean temperature of 90 K.[16] The cooler secondary companion has a class of F3 V.[5] The system appears to be a source of X-ray emission.[17]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Gray, R. O. et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G. 
  4. ↑ Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  5. ↑ 5.0 5.1 5.2 Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  6. ↑ 6.0 6.1 Cousins, A. W. J. (1973). "UBV Photometry of Some Southern Stars (Second List)". Monthly Notes of the Astron. Soc. Southern Africa 32: 11. Bibcode: 1973MNSSA..32...11C. 
  7. ↑ 7.0 7.1 Bopp, B. W. et al. (1970). "Orbital elements of six spectroscopic binary stars". Monthly Notices of the Royal Astronomical Society 147 (4): 355–366. doi:10.1093/mnras/147.4.355. Bibcode: 1970MNRAS.147..355B. 
  8. ↑ "* pi. PsA". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+pi.+PsA. 
  9. ↑ "/ftp/cats/more/HIP/cdroms/cats". Strasbourg astronomical Data Center. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats. 
  10. ↑ 10.0 10.1 Janot-Pacheco, E. (August 1974). "On the cepheid nature of pi PsA". Astronomy and Astrophysics 34: 325–326. Bibcode: 1974A&A....34..325J. 
  11. ↑ "pi PsA". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=26602. 
  12. ↑ Thomas, Axel (June 1991). "Π PsA - Who Are You?". The Journal of the American Association of Variable Star Observers 20 (1): 23–24. Bibcode: 1991JAVSO..20...23T. https://articles.adsabs.harvard.edu/pdf/1991JAVSO..20...23T. Retrieved 1 January 2023. 
  13. ↑ Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society 331 (1): 45–59. doi:10.1046/j.1365-8711.2002.05150.x. Bibcode: 2002MNRAS.331...45K. https://academic.oup.com/mnras/article/331/1/45/1034740. Retrieved 1 January 2023. 
  14. ↑ "pi. PsA". Sternberg Astronomical Institute, Moscow University. http://www.sai.msu.su/gcvs/cgi-bin/search2.cgi?search=pi.+PsA. 
  15. ↑ Petit, Michel (July 1972). "Pi PsA". Information Bulletin on Variable Stars 695 (2): 2. Bibcode: 1972IBVS..695....2P. https://ibvs.konkoly.hu/pub/ibvs/0601/0695.pdf. Retrieved 1 January 2023. 
  16. ↑ Cotten, Tara H.; Song, Inseok (July 2016). "A Comprehensive Census of Nearby Infrared Excess Stars". The Astrophysical Journal Supplement Series 225 (1): 24. doi:10.3847/0067-0049/225/1/15. 15. Bibcode: 2016ApJS..225...15C. 
  17. ↑ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement 184 (1): 138–151. doi:10.1088/0067-0049/184/1/138. Bibcode: 2009ApJS..184..138H. 

External links



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