Location of TZ Arietis in the constellation Aries | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aries |
Right ascension | 02h 00m 12.95632s [1] |
Declination | +13° 03′ 07.0006″ [1] |
Apparent magnitude (V) | 12.298 [2] |
Characteristics | |
Spectral type | M4.5 V [3] |
U−B color index | +1.37 [4] |
B−V color index | +1.80 [4] |
R−I color index | 1.39 [3] |
Variable type | Flare star |
Astrometry | |
Radial velocity (Rv) | −28.29±0.25 [1] km/s |
Proper motion (μ) | RA: 1096.458 mas/yr [1] Dec.: -1771.526 mas/yr [1] |
Parallax (π) | 223.7321 ± 0.0699 mas [1] |
Distance | 14.578 ± 0.005 ly (4.470 ± 0.001 pc) |
Absolute magnitude (MV) | 14.03 [5] |
Details | |
Mass | 0.14 [6] M☉ |
Radius | 0.161 [7] R☉ |
Luminosity | 0.00135 [8] L☉ |
Surface gravity (log g) | 5.05 [6] cgs |
Temperature | 3,158 [7] K |
Metallicity [Fe/H] | −0.14 [7] dex |
Rotational velocity (v sin i) | 3.8 [8] km/s |
Age | 4.8 [6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
TZ Arietis (also known as Gliese 83.1, GJ 9066, or L 1159-16) is a red dwarf in the northern constellation of Aries. With a normal apparent visual magnitude of 12.3, it is too faint to be seen by the naked eye, although it lies relatively close to the Sun at a distance of 14.6 light-years (4.47 parsecs ). It is a flare star, which means it can suddenly increase in brightness for short periods of time.
TZ Arietis is a variable star. It is a flare star, showing brief increases in brightness due to eruptions from its surface. In the ultraviolet, flares of over a magnitude have been observed. In addition it shows longterm variations in brightness which may be due to starspots and rotation, possibly classifying it as a BY Draconis variable. [10] It was given the variable star designation TZ Arietis in 1970. [11]
In a preprint submitted to arXiv in June 2019, three candidate planets were reported in orbit around this star (GJ 83.1) with orbital periods of 2, 240, and 770 days. [12] A paper published in August 2020 reported a confirmation of the 240-day and 770-day planets, designating them "b" and "c", respectively. [13]
In March 2022, astronomers using the Calar Alto Observatory in Spain, as part of the CARMENES survey project, reported an independent confirmation of the 770-day planet, which they designated "b". However, they found no evidence for the 240-day planet, and confidently defined the 2-day candidate as nothing more than a spurious chromatic effect of the star, linked to its rotation. [14] The NASA Exoplanet Archive still refers to the confirmed, 770-day planet as "c". [15]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b [note 1] | ≥0.21±0.02 MJ | 0.88±0.02 | 771.36+1.34 −1.23 | 0.46±0.04 | — | — |
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