NGTS-1, also designated as TOI-551 is a solitary star located in the southern constellation Columba, the dove. With an apparent magnitude of 15.52,[2] NGTS-1 can only be seen through a powerful telescope. Gaia DR3 parallax measurements imply a distance of 710 light-years[1] and it is drifting away rapidly with a heliocentric radial velocity of 97.2 km/s.[3]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Columba |
| Right ascension | 05h 30m 51.45227s[1] |
| Declination | −36° 37′ 50.8957″[1] |
| Apparent magnitude (V) | 15.57±0.03[2] |
| Characteristics | |
| Evolutionary stage | main sequence star[3] |
| Spectral type | M0.5[3] |
| B−V color index | +1.37[2] |
| R−I color index | +1.39[4] |
| Astrometry | |
| Radial velocity (Rv) | 97.18±0.01[3] km/s |
| Proper motion (μ) | RA: −31.887 mas/yr[1] Dec.: −41.077 mas/yr[1] |
| Parallax (π) | 4.5935 ± 0.017 mas[1] |
| Distance | 710 ± 3 ly (217.7 ± 0.8 pc) |
| Details[3] | |
| Mass | 0.617+0.023 −0.062 M☉ |
| Radius | 0.573±0.077 R☉ |
| Luminosity | (7.03±0.09)×10−2[5] L☉ |
| Surface gravity (log g) | 4.71±0.23 cgs |
| Temperature | 3,916+71 −63 K |
| Rotational velocity (v sin i) | <1.0 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Properties
NGTS-1 has a stellar classification of M0.5, indicating that is an early M-type star. It has 61% of the mass of the Sun and over half of its radius.[3] Since red dwarfs are fully convective, they do not burn as much as more massive stars. As a result, NGTS-1 only radiates 7.02% of the luminosity of the Sun from its photosphere at an effective temperature of 3,916 K.[3] There was difficulty determining the metallicity of the object due to its faintness, but NGTS-1 is assumed to be around solar metallicity.[3] In addition, this also provided some uncertainty about the star's properties since red dwarfs properties are dependent on their metallicity. It spins too slowly for it to be measured accurately, having a projected rotational velocity lower than 1.0 km/s.[3]
Planetary system
The discovery of a hot Jupiter orbiting the star was reported in 2017 as part of the Next Generation Transit Survey.[3] The media also dubbed NGTS-1b as "monstrous" since the planet is relatively large compared to its host star.[6]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 0.812+0.066 −0.075 MJ | 0.0326+0.0047 −0.0045 | 2.6473068±0.0000017[7] | 0.016+0.023 −0.012 | 85.27+0.61 −0.73° | 1.33+0.61 −0.33 RJ |