Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Tucana |
DS Tucanae A | |
Right ascension | 23h 39m 39.48081s [1] |
Declination | −69° 11′ 44.7077″ [1] |
Apparent magnitude (V) | 8.47 [2] |
DS Tucanae B | |
Right ascension | 23h 39m 39.26965s [3] |
Declination | −69° 11′ 39.4936″ [3] |
Apparent magnitude (V) | 9.84 [4] |
Characteristics | |
Spectral type | G6V+K3V [4] |
Variable type | RS CVn [5] |
Astrometry | |
A | |
Radial velocity (Rv) | 7.20 [6] km/s |
Proper motion (μ) |
RA: 79.529
[1]
mas/
yr Dec.: −67.551 [1] mas/ yr |
Parallax (π) | 22.6367 ± 0.0150 mas [1] |
Distance | 144.08 ± 0.10
ly (44.18 ± 0.03 pc) |
B | |
Radial velocity (Rv) | 5.32 [7] km/s |
Proper motion (μ) |
RA: 78.133
[3]
mas/
yr Dec.: −65.845 [3] mas/ yr |
Parallax (π) | 22.6524 ± 0.0125 mas [3] |
Distance | 143.98 ± 0.08
ly (44.15 ± 0.02 pc) |
Details | |
DS Tucanae A | |
Mass | 1.01±0.06 [8] M☉ |
Radius | 0.964±0.029 [8] R☉ |
Luminosity | 0.725±0.013 [8] L☉ |
Temperature | 5,428±80 [8] K |
Rotational velocity (v sin i) | 27.75+1.73 −1.54 [9] km/s |
Age | 45±4 [8] Myr |
DS Tucanae B | |
Mass | 0.84±0.06 [8] M☉ |
Radius | 0.864±0.036 [8] R☉ |
Luminosity | 0.327±0.010 [8] L☉ |
Temperature | 4,700±90 [8] K |
Age | 45±4 [8] Myr |
Other designations | |
Database references | |
SIMBAD | AB |
A | |
B | |
Ab |
DS Tucanae (HD 222259) is a binary star system 144 light years away in the constellation of Tucana. It has an apparent visual magnitude of 8.5, [8] and is a RS Canum Venaticorum variable. [5] The system is notable for being young as a member of the 45 Myr old Tucana-Horologium moving group [10] and for the primary star hosting the confirmed exoplanet DS Tucanae Ab, discovered by THYME, using TESS. [11] [8] [12] [13]
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]
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. [16]
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.
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | <14.4 [9] M🜨 | 0.18+0.13 −0.12 |
8.138268 | — | 88.73+0.18 −0.17 [9] ° |
5.70±0.17 R🜨 |
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 ME. [12] DS Tuc Ab will be observed by ESA's CHEOPS mission to characterize the planet. [17]
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.
[18]
[19] DS Tucanae Ab might therefore be a good target to study
in-situ planet-formation of short-period planets.
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Tucana |
DS Tucanae A | |
Right ascension | 23h 39m 39.48081s [1] |
Declination | −69° 11′ 44.7077″ [1] |
Apparent magnitude (V) | 8.47 [2] |
DS Tucanae B | |
Right ascension | 23h 39m 39.26965s [3] |
Declination | −69° 11′ 39.4936″ [3] |
Apparent magnitude (V) | 9.84 [4] |
Characteristics | |
Spectral type | G6V+K3V [4] |
Variable type | RS CVn [5] |
Astrometry | |
A | |
Radial velocity (Rv) | 7.20 [6] km/s |
Proper motion (μ) |
RA: 79.529
[1]
mas/
yr Dec.: −67.551 [1] mas/ yr |
Parallax (π) | 22.6367 ± 0.0150 mas [1] |
Distance | 144.08 ± 0.10
ly (44.18 ± 0.03 pc) |
B | |
Radial velocity (Rv) | 5.32 [7] km/s |
Proper motion (μ) |
RA: 78.133
[3]
mas/
yr Dec.: −65.845 [3] mas/ yr |
Parallax (π) | 22.6524 ± 0.0125 mas [3] |
Distance | 143.98 ± 0.08
ly (44.15 ± 0.02 pc) |
Details | |
DS Tucanae A | |
Mass | 1.01±0.06 [8] M☉ |
Radius | 0.964±0.029 [8] R☉ |
Luminosity | 0.725±0.013 [8] L☉ |
Temperature | 5,428±80 [8] K |
Rotational velocity (v sin i) | 27.75+1.73 −1.54 [9] km/s |
Age | 45±4 [8] Myr |
DS Tucanae B | |
Mass | 0.84±0.06 [8] M☉ |
Radius | 0.864±0.036 [8] R☉ |
Luminosity | 0.327±0.010 [8] L☉ |
Temperature | 4,700±90 [8] K |
Age | 45±4 [8] Myr |
Other designations | |
Database references | |
SIMBAD | AB |
A | |
B | |
Ab |
DS Tucanae (HD 222259) is a binary star system 144 light years away in the constellation of Tucana. It has an apparent visual magnitude of 8.5, [8] and is a RS Canum Venaticorum variable. [5] The system is notable for being young as a member of the 45 Myr old Tucana-Horologium moving group [10] and for the primary star hosting the confirmed exoplanet DS Tucanae Ab, discovered by THYME, using TESS. [11] [8] [12] [13]
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]
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. [16]
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.
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | <14.4 [9] M🜨 | 0.18+0.13 −0.12 |
8.138268 | — | 88.73+0.18 −0.17 [9] ° |
5.70±0.17 R🜨 |
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 ME. [12] DS Tuc Ab will be observed by ESA's CHEOPS mission to characterize the planet. [17]
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.
[18]
[19] DS Tucanae Ab might therefore be a good target to study
in-situ planet-formation of short-period planets.