| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 15h 33m 51.0571s |
| Declination | +63° 54′ 25.6950″ |
| Apparent magnitude (V) | 7.46[2] |
| Characteristics | |
| HD 139319A | |
| Spectral type | A8V+K0III [3] |
| Apparent magnitude (g) | 7.39[4] |
| HD 139319B | |
| Spectral type | F7V |
| Apparent magnitude (g) | 9.65[5] |
| Astrometry | |
| HD 139319A | |
| Proper motion (μ) | RA: 11.44±0.03 mas/yr[4] Dec.: 22.39±0.02 mas/yr[4] |
| Parallax (π) | 6.0571 ± 0.0179 mas[4] |
| Distance | 538 ± 2 ly (165.1 ± 0.5 pc) |
| HD 139319B | |
| Radial velocity (Rv) | 1.6±0.7[5] km/s |
| Proper motion (μ) | RA: 12.09±0.02 mas/yr[5] Dec.: 21.278±0.018 mas/yr[5] |
| Parallax (π) | 6.0345 ± 0.0160 mas[5] |
| Distance | 540 ± 1 ly (165.7 ± 0.4 pc) |
| Orbit[6] | |
| Primary | TW Draconis A |
| Companion | TW Draconis B |
| Period (P) | 2.8068491 d |
| Semi-major axis (a) | 0.057 AU |
| Inclination (i) | 86.8° |
| Semi-amplitude (K1) (primary) | 64.05 km/s |
| Semi-amplitude (K2) (secondary) | 150 km/s |
| Details[7] | |
| TW Draconis A | |
| Mass | 2.16±0.11 M☉ |
| Radius | 2.64±0.04 R☉ |
| Surface gravity (log g) | 3.928±0.026 cgs |
| Temperature | 7815±92 K |
| TW Draconis B | |
| Mass | 0.93±0.05 M☉ |
| Radius | 3.66±0.06 R☉ |
| Surface gravity (log g) | 3.314±0.026 cgs |
| Temperature | 4442±32 K |
| Other designations | |
BD+64 1077, HIP 76196, 2MASS J15335104+6354257, GSC 04184-00061 | |
| HD 139319A: TW Draconis, TYC 4184-61-1, Gaia DR2 1640708022815757568 | |
| HD 139319B: TYC 4184-61-2, Gaia DR2 1640708022815757824 | |
| Database references | |
| SIMBAD | data |
HD 139319 is a ternary system composed of the binary Algol variable star known as TW Draconis, and a main-sequence companion star at a separation of 3 arcseconds.[6] The system lies in the constellation of Draco about 540 light years away.
- ^ Cite error: The named reference
MASTwas invoked but never defined (see the help page). - ^ "TW Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-12-13.
- ^ Cite error: The named reference
Kim2003was invoked but never defined (see the help page). - ^ a b c Cite error: The named reference
EDR3Awas invoked but never defined (see the help page). - ^ a b c d Cite error: The named reference
EDR3Bwas invoked but never defined (see the help page). - ^ a b Liao, Wen-Ping; Qian, Sheng-Bang; Zejda, Miloslav; Zhu, Li-Ying; Li, Lin-Jia (2016), "Lunar-based Ultraviolet Telescope study of the well-known Algol-type binary TW Dra", Research in Astronomy and Astrophysics, 16 (6): 009, Bibcode:2016RAA....16...94L, doi:10.1088/1674-4527/16/6/094, S2CID 124656327
- ^ Bozic, H.; Nemravova, J.; Harmanec, P. (2013), "Standard UBV photometry and improved physical properties of TW Dra", Information Bulletin on Variable Stars, 6086: 1, Bibcode:2013IBVS.6086....1B