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TW Piscis Austrini: Difference between revisions

Coordinates: Sky map 22h 56m 24.0533s, −31° 33′ 56.0351″
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{{Short description|Star in the constellation Piscis Austrinus}}
{{Short description|Star in the constellation Piscis Austrinus}}
{{Redirect|Fomalhaut B|the former exoplanet candidate|Fomalhaut b}}
{{Redirect|Fomalhaut B|the former exoplanet candidate|Fomalhaut b}}
{{Sky|22|56|24.0533|-|31|33|56.0351|24.8}}
{{Starbox begin
{{Starbox begin
| name=TW Piscis Austrini
| name=TW Piscis Austrini
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}}
}}
{{Starbox detail
{{Starbox detail
| mass={{nowrap|0.725 ± 0.036}}<ref name=aaa505_1_205/>
| source=<ref name=Gomes2021/>
| radius={{nowrap|0.629 ± 0.051}}<ref name=aaa505_1_205/>
| mass={{val|0.704|0.016}}
| radius={{val|0.658|0.009}}
| luminosity=0.19<ref name="age_mam"/>
| luminosity=0.19<ref name="age_mam"/>
| temperature={{nowrap|4,711 ± 134}}<ref name=aaa505_1_205/>
| temperature={{val|4610|67|fmt=commas}}
| metal_fe={{val|-0.07|0.03}}
| metal=
| rotation=10.3<ref name=Mamajek/> days
| rotation=10.3<ref name=Mamajek/> days
| rotational_velocity=2.93<ref name=aaa505_1_205/>
| rotational_velocity=2.93<ref name=aaa505_1_205/>
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TW Piscis Austrini lies within a light-year of Fomalhaut.<ref name=schaaf2008/> Due to sharing the same [[proper motion]], and the same estimated age of approximately 440 ± 40 million years, astronomers now consider them to be elements of a multiple [[star system]].<ref name="age_mam"/> A third star, dimmer and more widely separated, [[Fomalhaut C]], gives the system the widest visual separation, to observers from Earth, at approximately 6 degrees.<ref name=skyandtelescope2014-10-01/>
TW Piscis Austrini lies within a light-year of Fomalhaut.<ref name=schaaf2008/> Due to sharing the same [[proper motion]], and the same estimated age of approximately 440 ± 40 million years, astronomers now consider them to be elements of a multiple [[star system]].<ref name="age_mam"/> A third star, dimmer and more widely separated, [[Fomalhaut C]], gives the system the widest visual separation, to observers from Earth, at approximately 6 degrees.<ref name=skyandtelescope2014-10-01/>
==Planetary System==
==Planetary system==
In 2019, an [[exoplanet]] candidate around Fomalhaut B was detected by [[astrometry]], but this remains unconfirmed.<ref name=space2019-09-23/><ref name=AstronomicalJournal2019-10-07/>
In 2019, an [[exoplanet]] candidate around Fomalhaut B was detected by [[astrometry]], but this remains unconfirmed.<ref name=space2019-09-23/><ref name=AstronomicalJournal2019-10-07/>


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<ref name=schaaf2008>{{cite book|author=Fred Schaaf|title=The Brightest Stars: Discovering the Universe through the Sky's Most Brilliant Stars|url=https://books.google.com/books?id=9LT1q0Il3-YC|date=31 March 2008|publisher=Wiley|isbn=978-0-470-24917-8}}</ref>
<ref name=schaaf2008>{{cite book|author=Fred Schaaf|title=The Brightest Stars: Discovering the Universe through the Sky's Most Brilliant Stars|url=https://books.google.com/books?id=9LT1q0Il3-YC|date=31 March 2008|publisher=Wiley|isbn=978-0-470-24917-8}}</ref>


<ref name=age_mam>{{Cite journal | last1=Mamajek | first1=E.E. | title=On the Age and Binarity of Fomalhaut | journal=Astrophysical Journal Letters | volume=754 | issue=2 |date=August 2012 | pages=L20 | doi=10.1088/2041-8205/754/2/L20 | arxiv=1206.6353| s2cid=119191190 }}</ref>
<ref name=age_mam>{{Cite journal | last1=Mamajek | first1=E.E. | title=On the Age and Binarity of Fomalhaut | journal=Astrophysical Journal Letters | volume=754 | issue=2 |date=August 2012 | pages=L20 | doi=10.1088/2041-8205/754/2/L20 | arxiv=1206.6353| bibcode=2012ApJ...754L..20M | s2cid=119191190 }}</ref>


<ref name=aaa505_1_205>{{cite journal
<ref name=aaa505_1_205>{{cite journal
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| arxiv = 1910.02965
| arxiv = 1910.02965
| doi = 10.3847/1538-3881/ab4c9b
| doi = 10.3847/1538-3881/ab4c9b
<!-- | class = astro-ph.EP -->
|bibcode = 2019AJ....158..225D
|bibcode = 2019AJ....158..225D
|s2cid = 203902656
|s2cid = 203902656
|doi-access = free
}}
}}
</ref>
</ref>
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| doi=10.1088/0004-6256/146/6/154
| doi=10.1088/0004-6256/146/6/154
| arxiv=1310.0764|s2cid=67821813}}</ref>
| arxiv=1310.0764|s2cid=67821813}}</ref>


<ref name=Gomes2021>{{Cite journal |last=Gomes da Silva |first=J. |last2=Santos |first2=N. C. |last3=Adibekyan |first3=V. |last4=Sousa |first4=S. G. |last5=Campante |first5=T. L. |last6=Figueira |first6=P. |last7=Bossini |first7=D. |last8=Delgado-Mena |first8=E. |last9=Monteiro |first9=M. J. P. F. G. |last10=de Laverny |first10=P. |last11=Recio-Blanco |first11=A. |last12=Lovis |first12=C. |date=2021-02-01 |title=Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity |url=https://ui.adsabs.harvard.edu/abs/2021A&A...646A..77G |journal=Astronomy and Astrophysics |volume=646 |pages=A77 |doi=10.1051/0004-6361/202039765 |issn=0004-6361|arxiv=2012.10199 }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/A%2BA/646/A77&Star=TW%20PsA Fomalhaut B's database entry] at [[VizieR]].</ref>


}}
}}
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==External links==
==External links==
* [http://www.solstation.com/stars/tw-psa.htm TW Piscis Austrini] at SolStation.
* [http://www.solstation.com/stars/tw-psa.htm TW Piscis Austrini] at SolStation.
{{Sky|22|56|24.0533|-|31|33|56.0351|24.8}}
{{Nearest star systems|6}}
{{Nearest star systems|6}}
{{Stars of Piscis Austrinus}}
{{Stars of Piscis Austrinus}}
{{Fomalhaut}}

{{DEFAULTSORT:TW Piscis Austrini}}
{{DEFAULTSORT:TW Piscis Austrini}}
[[Category:Piscis Austrinus]]
[[Category:Piscis Austrinus]]
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[[Category:Gliese and GJ objects|0879]]
[[Category:Gliese and GJ objects|0879]]
[[Category:Durchmusterung objects|CD-32 17321]]
[[Category:Durchmusterung objects|CD-32 17321]]
[[Category:Fomalhaut]]

Latest revision as of 23:47, 15 July 2024

TW Piscis Austrini
Location of TW Piscis Austrini (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Piscis Austrinus
Right ascension 22h 56m 24.05256s[1]
Declination −31° 33′ 56.0306″[1]
Apparent magnitude (V) 5.44–6.51[2]
Characteristics
Spectral type K5Vp[3]
U−B color index 1.02[4]
B−V color index 1.10[4]
Variable type BY Draconis[2]
Astrometry
Radial velocity (Rv)+6.79±0.12[1] km/s
Proper motion (μ) RA: 330.203 mas/yr[1]
Dec.: −158.602 mas/yr[1]
Parallax (π)131.5525 ± 0.0275 mas[1]
Distance24.793 ± 0.005 ly
(7.602 ± 0.002 pc)
Absolute magnitude (MV)7.08[5]
Details[6]
Mass0.704±0.016 M
Radius0.658±0.009 R
Luminosity0.19[5] L
Temperature4,610±67 K
Metallicity [Fe/H]−0.07±0.03 dex
Rotation10.3[7] days
Rotational velocity (v sin i)2.93[3] km/s
Age440[5] Myr
Other designations
TW PsA, Gl 879, HR 8721, CD−32°17321, HD 216803, LTT 9283, GCTP 5562.00, SAO 214197, CP(D)−32°6550, HIP 113283[8]
Database references
SIMBADdata
ARICNSdata

TW Piscis Austrini (also known as Fomalhaut B) is a main sequence star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.8 light-years (7.6 parsecs). To an observer on Earth the star is visually separated from its larger companion Fomalhaut (A) by 2 degrees—the width of four full moons.[9]

A visual band light curve for TW Piscis Austrini, adapted from Busko and Torres (1978).[10] The error bar shown on the left-most point applies to all points.

The name TW Piscis Austrini is a variable star designation. This is a variable star of the type known as a BY Draconis variable, with surface brightness variations causing the changes as the star rotates. It varies slightly in apparent magnitude, ranging from 6.44 to 6.51 over a 10.3-day period.[2]

TW Piscis Austrini lies within a light-year of Fomalhaut.[11] Due to sharing the same proper motion, and the same estimated age of approximately 440 ± 40 million years, astronomers now consider them to be elements of a multiple star system.[5] A third star, dimmer and more widely separated, Fomalhaut C, gives the system the widest visual separation, to observers from Earth, at approximately 6 degrees.[9]

Planetary system

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In 2019, an exoplanet candidate around Fomalhaut B was detected by astrometry, but this remains unconfirmed.[12][13]

The Fomalhaut B planetary system[13]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(years)
Eccentricity Inclination Radius
b (unconfirmed) 1.2+0.7
−0.6
MJ
25+52
−21

References

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  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  3. ^ a b Demory, Brice-Olivier; Ségransan, Damien; Forveille, Thierry; Queloz, Didier; Beuzit, Jean-Luc; Delfosse, Xavier; Di Folco, Emmanuel; Kervella, Pierre; Le Bouquin, Jean-Baptiste; Perrier, Christian; Benisty, Myriam; Duvert, Gilles; Hofmann, Karl-Heinz; Lopez, Bruno; Petrov, Romain (October 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics. 505 (1): 205–215. arXiv:0906.0602. Bibcode:2009A&A...505..205D. doi:10.1051/0004-6361/200911976. S2CID 14786643.
  4. ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  5. ^ a b c d Mamajek, E.E. (August 2012). "On the Age and Binarity of Fomalhaut". Astrophysical Journal Letters. 754 (2): L20. arXiv:1206.6353. Bibcode:2012ApJ...754L..20M. doi:10.1088/2041-8205/754/2/L20. S2CID 119191190.
  6. ^ Gomes da Silva, J.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Campante, T. L.; Figueira, P.; Bossini, D.; Delgado-Mena, E.; Monteiro, M. J. P. F. G.; de Laverny, P.; Recio-Blanco, A.; Lovis, C. (2021-02-01). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy and Astrophysics. 646: A77. arXiv:2012.10199. doi:10.1051/0004-6361/202039765. ISSN 0004-6361. Fomalhaut B's database entry at VizieR.
  7. ^ Mamajek, Eric E.; et al. (2013). "The Solar Neighborhood. XXX. Fomalhaut C". The Astronomical Journal. 146 (6): 154–163. arXiv:1310.0764. Bibcode:2013AJ....146..154M. doi:10.1088/0004-6256/146/6/154. S2CID 67821813.
  8. ^ "V* TW PsA -- Variable of BY Dra type". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-01-20.
  9. ^ a b Bob King (2014-10-01). "Fomalhaut: A crazy-wide triple stat". Sky & Telescope. Retrieved 2020-06-13. Though it may appear isolated in the barren October sky, Fomalhaut has company. It feels the gravitational tug of the magnitude +6.5 star TW Piscis Austrini, 2° to the south. Both are 25 light-years distant and move in tandem across space, partaking of the same proper motion. They form a true double star with an actual separation of 5.5 trillion miles, or 0.91 light-year.
  10. ^ Busko, I. C.; Torres, C. A. O. (March 1978). "Flare activity by BY Draconis stars". Astronomy and Astrophysics. 64: 153–160. Bibcode:1978A&A....64..153B. Retrieved 23 February 2022.
  11. ^ Fred Schaaf (31 March 2008). The Brightest Stars: Discovering the Universe through the Sky's Most Brilliant Stars. Wiley. ISBN 978-0-470-24917-8.
  12. ^ Joe Rao (2019-09-23). "Fomalhaut, 'Royal' Star of Autumn, Swims with the Southern Fish". Space.com. Retrieved 2020-06-13. Believe it or not, an extrasolar planet might also be circling TW Piscis Austrini. NASA's Transiting Exoplanet Survey Satellite (TESS), a space telescope that's searching for planets around the brightest stars in Earth's night sky, recently found a possible candidate circling this star. It's almost the same size as our Earth, and orbits the star about every 10 days at a distance of 7.5 million miles from it.
  13. ^ a b De Rosa, Robert J.; Esposito, Thomas M.; Hirsch, Lea A.; Nielsen, Eric L.; Marley, Mark S.; Kalas, Paul; Wang, Jason J.; Macintosh, Bruce (7 October 2019). "The Possible Astrometric Signature of a Planetary-mass Companion to the Nearby Young Star TW Piscis Austrini (Fomalhaut B): Constraints from Astrometry, Radial Velocities, and Direct Imaging". Astronomical Journal. 158 (6): 225. arXiv:1910.02965. Bibcode:2019AJ....158..225D. doi:10.3847/1538-3881/ab4c9b. S2CID 203902656.
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