Map of stars and open clusters within 100 parsecs of the Sun. The Tucana-Horologium association is at 285° galactic longitude.

The Tucana-Horologium association (Tuc-Hor), or Tucana Horologium moving group, is a stellar association with an age of 45 ± 4 Myr[1] and it is one of the largest stellar associations within 100 parsecs (330 light-years). The association has a similar size to the Beta Pictoris moving group (BPMG) and contains, like BPMG, more than 12 stars with spectral type B, A and F.[2] The association is named after two southern constellations, the constellation Tucana and the constellation Horologium.

The group was at first not recognized as an individual group, but stars within the group were first assigned to the Great Austral Young Association (GAYA). Only later did it become clear that this complex is divided into three groups: the Tucana-Horologium association, the Carina association and the Columba association.[3]

Members

The members of this young group are potential targets for directly imaged circumstellar disks and exoplanets.[2] The stars are located close to Earth and the planets are young, so they give off more infrared light, which is suited for directly imaging techniques. AB Pictoris was considered a member of Tuc-Hor, but it is more likely a member of the Carina association.[4]

The brightest-identified member of the association is the massive star Alpha Pavonis, which is leaving the main sequence. The association also contains stars of the Beta Tucanae group.[3] Another notable member is DS Tucanae, which is a binary star, with the primary having one exoplanet transiting in front of the star.

Debris disks have been detected around some members. Examples are HD 1466, HD 10472, DK Ceti, CPD-74 192, HD 21997, HD 32195, HD 37484, HD 38206, V1358 Orionis and HD 85672.[5] The star HD 202917 has a debris disk that was directly imaged with the Hubble Space Telescope.[6] The brown dwarf 2MASS J02265658-5327032 is likely a member of the Tuc-Hor association and has a circumstellar disk, which is unusual for its age. Some researchers call these relatively old disks Peter Pan disks.[7][8]

Examples of directly imaged planets in the association are 2MASS 0219-3925 b[9] and 2MASS 0103(AB) b.[10]

The list below shows some members of the group. The list is focused on B-type, A-type and F-type stars and other stars/brown dwarfs are included if they are notable. The list is sorted after the brightness.

List of members[1][3][11][12]
Name distance (light-years) spectral type brightness (V-mag)
α Pavonis 179 B2IV 1.91
φ Eridani 154 B8V 3.56
ε Hydri 152 B9IV 4.12
HD 2884 135 B9V 4.36
HD 24072 172 B9.5Van 4.71
HD 2885 166 A2V 4.77
η Tucanae 154 A1Va+n 4.99
HD 3003 150 A0V 5.07
HD 24071 172 A1Va 5.25
HD 20121 139 F4V+F9V 6.01
HD 154431 181 A5V 6.07
HD 19545 177 A3V 6.18
HD 12894 151 F4V 6.45
HD 207964 152 F0IV 6.56
HD 200798 227 A5/6IV/V 6.70
HD 30051 220 F2IV 7.12
HD 24636 186 F3IV/V 7.13
HD 207575 153 F6V 7.22
HD 1466 140 F8V 7.45
HD 53842 189 F5V 7.46
HD 20385 159 F6V 7.49
HD 13246 149 F7V 7.50
HD 17250 186 F7V 7.88
HD 32195 205 F7V 8.12
DS Tucanae 149 G6V 8.49
DK Ceti 135 G4V 8.66
HD 202917[6] 153 G7V 8.67
BS Indi 172 G9V 8.87
CC Phoenicis 130 K1V 9.38
BO Microscopii 218 K3Ve 9.45
V857 Arae 194 G8V 9.50
AT Columbae 254 K1Ve 9.58
CT Tucanae 144 M0Ve 11.47
GJ 3054 134 M1.5V 11.97
AF Horologii 142 M2Ve 12.13
2MASS 0103[10] 154 M5.0+L 15.40[13]
2MASS 0219-3925[9] 131 M6γ+L4γ 11.32 (J-band)
2MASS J02265658-5327032[7] 152 L0δ 15.40 (J-band)

See also

References

  1. 1 2 Bell, Cameron P. M.; Mamajek, Eric E.; Naylor, Tim (November 2015). "A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood". MNRAS. 454 (1): 593–614. arXiv:1508.05955. Bibcode:2015MNRAS.454..593B. doi:10.1093/mnras/stv1981. ISSN 0035-8711.
  2. 1 2 Kraus, Adam L.; Shkolnik, Evgenya L.; Allers, Katelyn N.; Liu, Michael C. (June 2014). "A Stellar Census of the Tucana-Horologium Moving Group". The Astronomical Journal. 147 (6): 146. arXiv:1403.0050. Bibcode:2014AJ....147..146K. doi:10.1088/0004-6256/147/6/146. ISSN 0004-6256. S2CID 67817454.
  3. 1 2 3 Torres, C. a. O.; Quast, G. R.; Melo, C. H. F.; Sterzik, M. F. (December 2008). "Young Nearby Loose Associations". Hsf2. 5: 757. Bibcode:2008hsf2.book..757T.
  4. ↑ Gagné, Jonathan; Mamajek, Eric E.; Malo, Lison; Riedel, Adric; Rodriguez, David; Lafrenière, David; Faherty, Jacqueline K.; Roy-Loubier, Olivier; Pueyo, Laurent; Robin, Annie C.; Doyon, René (March 2018). "BANYAN. XI. The BANYAN Σ Multivariate Bayesian Algorithm to Identify Members of Young Associations with 150 pc". Astrophysical Journal. 856 (1): 23. arXiv:1801.09051. Bibcode:2018ApJ...856...23G. doi:10.3847/1538-4357/aaae09. ISSN 0004-637X.
  5. ↑ Meshkat, Tiffany; Mawet, Dimitri; Bryan, Marta L.; Hinkley, Sasha; Bowler, Brendan P.; Stapelfeldt, Karl R.; Batygin, Konstantin; Padgett, Deborah; Morales, Farisa Y.; Serabyn, Eugene; Christiaens, Valentin (December 2017). "A Direct Imaging Survey of Spitzer-detected Debris Disks: Occurrence of Giant Planets in Dusty Systems". The Astronomical Journal. 154 (6): 245. arXiv:1710.04185. Bibcode:2017AJ....154..245M. doi:10.3847/1538-3881/aa8e9a. ISSN 0004-6256.
  6. 1 2 Schneider, Glenn; Grady, Carol A.; Stark, Christopher C.; Gaspar, Andras; Carson, Joseph; Debes, John H.; Henning, Thomas; Hines, Dean C.; Jang-Condell, Hannah; Kuchner, Marc J.; Perrin, Marshall (September 2016). "Deep HST/STIS Visible-light Imaging of Debris Systems around Solar Analog Hosts". The Astronomical Journal. 152 (3): 64. arXiv:1606.00039. Bibcode:2016AJ....152...64S. doi:10.3847/0004-6256/152/3/64. ISSN 0004-6256.
  7. 1 2 Boucher, Anne; Lafrenière, David; Gagné, Jonathan; Malo, Lison; Faherty, Jacqueline K.; Doyon, René; Chen, Christine H. (November 2016). "BANYAN. VIII. New Low-mass Stars and Brown Dwarfs with Candidate Circumstellar Disks". Astrophysical Journal. 832 (1): 50. arXiv:1608.08259. Bibcode:2016ApJ...832...50B. doi:10.3847/0004-637X/832/1/50. ISSN 0004-637X.
  8. ↑ Silverberg, Steven M.; Wisniewski, John P.; Kuchner, Marc J.; Lawson, Kellen D.; Bans, Alissa S.; Debes, John H.; Biggs, Joseph R.; Bosch, Milton K. D.; Doll, Katharina; Luca, Hugo A. Durantini; Enachioaie, Alexandru (February 2020). "Peter Pan Disks: Long-lived Accretion Disks Around Young M Stars". Astrophysical Journal. 890 (2): 106. arXiv:2001.05030. Bibcode:2020ApJ...890..106S. doi:10.3847/1538-4357/ab68e6. ISSN 0004-637X.
  9. 1 2 Artigau, Étienne; Gagné, Jonathan; Faherty, Jacqueline; Malo, Lison; Naud, Marie-Eve; Doyon, René; Lafrenière, David; Beletsky, Yuri (June 2015). "BANYAN. VI. Discovery of a Companion at the Brown Dwarf/Planet-Mass Limit to a Tucana-Horologium M Dwarf". Astrophysical Journal. 806 (2): 254. arXiv:1505.01747. Bibcode:2015ApJ...806..254A. doi:10.1088/0004-637X/806/2/254. ISSN 0004-637X. S2CID 119227877.
  10. 1 2 Delorme, P.; Gagné, J.; Girard, J. H.; Lagrange, A. M.; Chauvin, G.; Naud, M.-E.; Lafrenière, D.; Doyon, R.; Riedel, A.; Bonnefoy, M.; Malo, L. (May 2013). "Direct-imaging discovery of a 12-14 Jupiter-mass object orbiting a young binary system of very low-mass stars". Astronomy & Astrophysics. 553: L5. arXiv:1303.4525. Bibcode:2013A&A...553L...5D. doi:10.1051/0004-6361/201321169. ISSN 0004-6361. S2CID 21725522.
  11. ↑ Gaia Collaboration (2018-08-01). "Gaia Data Release 2 - Summary of the contents and survey properties". Astronomy & Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361.
  12. ↑ van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. ISSN 0004-6361. S2CID 18759600.
  13. ↑ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (July 2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". YCat: I/322A. Bibcode:2012yCat.1322....0Z.
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