DS Tucanae is a visual binary.[4] The binary consists of a G6V primary and a K3V secondary separated by 5″.[15] Based on radial velocity measurements it was suggested that the secondary itself is a binary, but later studies could not find evidence for this claim.[8]
Together with the red dwarf 2MASS J23321028–6926537, DS Tucanae might be a triple stellar system. This star shares a similar distance and similar proper motions. It is separated 113,000astronomical units from DS Tuc.[16]
Physical properties
In 1996, analysis of the Hipparcos data showed that the star is a variable star. It was given its variable star designation in 1999.[17]
High levels of magnetic activity, a strong 6708Å lithium line, and the position on the color-magnitude diagram, slightly above the main sequence, strongly support a young age of the system.[12] The primary star is emitting a frequent and powerful (up to 5-8×1034 ergs) X-ray flares.[18]
Both components of the binary are main sequence stars. The primary has a mass very similar to the Sun, but slightly cooler and smaller, meaning it is only 72% as luminous as the Sun. The secondary is only 84% as massive as the Sun and only 33% as luminous.
DS Tuc Ab is one of the few transiting planets with an age smaller than 100 Myrs. Other examples are K2-33b, V1298 Tauri b and AU Microscopii b. Of these systems DS Tuc is the brightest and it is a good target for atmospheric characterization with JWST. The planet is a super-Neptune or sub-Saturn.[8] The planet might be an inflated planet with an upper mass limit of 20 M🜨.[12] DS Tuc Ab will be observed by ESA's CHEOPS mission to characterize the planet.[19]
The planet DS Tucanae Ab has a low orbital obliquity (λ = 2.93°+0.88° −0.87° or λ = 12°±13°). This means that the orbital plane of this planet aligns with the stellar equator of the star. This is unusual for a short period planet. Many short period planets show high orbital obliquity, which was taken as a sign of the scattering of the planet into this short period orbit. It can also be interpreted as the formation of a planet in an inner disk with an axial tilt. But these previous measurements of orbital obliquity were made for giant planets around mature stars. DS Tucanae Ab is a relatively small young planet. This suggests that DS Tucanae Ab formed in a smooth disk that was not perturbed by the stellar companion DS Tucanae B.[20][21] DS Tucanae Ab might therefore be a good target to study in-situ planet-formation of short-period planets.
1 2 Samus', N. N.; Goranskii, V. P.; Durlevich, O. V.; Zharova, A. V.; Kazarovets, E. V.; Kireeva, N. N.; Pastukhova, E. N.; Williams, D. B.; Hazen, M. L. (July 2003). "An Electronic Version of the Second Volume of the General Catalogue of Variable Stars with Improved Coordinates". Astronomy Letters. 29 (7): 468–479. Bibcode:2003AstL...29..468S. doi:10.1134/1.1589864. ISSN1063-7737. S2CID16299532.
1 2 3 Benatti, S.; Damasso, M.; Borsa, F.; Locci, D.; Pillitteri, I.; Desidera, S.; Maggio, A.; Micela, G.; Wolk, S.; Claudi, R.; Malavolta, L.; Modirrousta-Galian, D. (2021), "Constraints on the mass and on the atmospheric composition and evolution of the low-density young planet DS Tucanae a B", Astronomy & Astrophysics, 650: A66, arXiv:2103.12922, Bibcode:2021A&A...650A..66B, doi:10.1051/0004-6361/202140416, S2CID234864890
↑ González-Payo, J.; Caballero, J. A.; Gorgas, J.; Cortés-Contreras, M.; Gálvez-Ortiz, M.-C.; Cifuentes, C. (2024-07-29). "Multiplicity of stars with planets in the solar neighbourhood". Astronomy & Astrophysics. 689: A302. arXiv:2407.20138. Bibcode:2024A&A...689A.302G. doi:10.1051/0004-6361/202450048.
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