GI Tauri and GK Tauri
Binary star system in the constellation of Taurus
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GK Tauri is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 421 light years away, belonging to the Taurus Molecular Cloud.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Taurus |
| GK Tauri | |
| Right ascension | 04h 33m 34.5627s[2] |
| Declination | +24° 21′ 05.854″[2] |
| Apparent magnitude (V) | 15.10 |
| GI Tauri | |
| Right ascension | 04h 33m 34.0609s[3] |
| Declination | +24° 21′ 17.067″[3] |
| Characteristics | |
| GK Tauri | |
| Evolutionary stage | pre-main-sequence star |
| Spectral type | K7[4] |
| Apparent magnitude (G) | 11.990[2] |
| Variable type | T Tau |
| GI Tauri | |
| Apparent magnitude (G) | 12.608[3] |
| Astrometry | |
| GK Tauri | |
| Proper motion (μ) | RA: 7.46±0.02 mas/yr[2] Dec.: −20.510±0.017 mas/yr[2] |
| Parallax (π) | 7.7433±0.0185 mas[2] |
| Distance | 421 ± 1 ly (129.1 ± 0.3 pc) |
| GI Tauri | |
| Proper motion (μ) | RA: 5.76±0.02 mas/yr[3] Dec.: −20.642±0.019 mas/yr[3] |
| Parallax (π) | 7.7258±0.0198 mas[3] |
| Distance | 422 ± 1 ly (129.4 ± 0.3 pc) |
| Position (relative to GK Tauri)[5] | |
| Component | GI Tauri |
| Angular distance | 13.15797±0.00005″ |
| Position angle | 328.4399±0.0002° |
| Projected separation | 1700 AU |
| Details[5] | |
| GK Tauri | |
| Mass | 0.79±0.07 M☉ |
| Luminosity | 0.80[6] L☉ |
| Temperature | 4007[6] K |
| Age | 2±1 Myr |
| GI Tauri | |
| Mass | 0.53+0.09 −0.11 M☉ |
| Luminosity | 0.49[6] L☉ |
| Temperature | 3792[6] K |
| Age | 2±1 Myr |
| Other designations | |
| GK Tauri: Gaia DR3 147790206908395776, 2MASS J04333456+2421058, GSC 01829-00040 | |
| GI Tauri: Gaia DR3 147790000749072768, 2MASS J04333405+2421170, GSC 01829-00082 | |
| Database references | |
| SIMBAD | data |
System
The stars GK Tauri and GI Tauri form a wide binary system, with the projected separation between components being 1700 AU. The secondary component's orbit is not very eccentric, with a periastron of at least 890 AU.[5]
GK Tauri was originally believed to have a close stellar companion WDS J04336+2421Ab.[7] However, it was found to be an unrelated background star according to Gaia data.[8]
Properties
Both members of the binary system are medium-mass objects still contracting towards the main sequence and accreting mass, with the primary GK Tauri being close to entering the main sequence.[4][5]
Protoplanetary system
Both stars are surrounded by compact protoplanetary disks, although the reason for the small disk sizes is not clear.[5] GK Tauri's spectrum indicates a possible gap in the protoplanetary disk and a planet orbiting within the gap, with a semimajor axis of 2.4+1.5
−1.0 AU.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| protoplanetary disk | 0–19 AU | 40.2+5.9 −6.2° |
— | |||
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| protoplanetary disk | 0–25 AU | 43.8±1.1° | — | |||