Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Pisces [a] |
Right ascension | 23h 35m 00.27674s [1] |
Declination | +01° 36′ 19.4347″ [1] |
Apparent magnitude (V) | 9.546 [1] |
Characteristics | |
A | |
Evolutionary stage | Main sequence |
Spectral type | K5-7 [2] |
B−V color index | 1.35 [3] |
B | |
Evolutionary stage | Main sequence |
Spectral type | M3-4 [2] |
C | |
Evolutionary stage | Main sequence |
Spectral type | M5-6 [2] |
Astrometry | |
Radial velocity (Rv) | −10.44±0.44 [4] km/s |
Proper motion (μ) | RA: 340.029 mas/yr [4] Dec.: 28.456 mas/yr [4] |
Parallax (π) | 47.9641 ± 0.0236 mas [4] |
Distance | 68.00 ± 0.03 ly (20.85 ± 0.01 pc) |
Absolute magnitude (MV) | 7.95 [b] |
Details | |
A | |
Mass | 0.64 –0.67 [2] M☉ |
Radius | 0.716±0.021 [5] R☉ |
Luminosity | 0.12±0.005 [4] L☉ |
Temperature | 4,079±180 [2] K |
Metallicity [Fe/H] | 0.02 [6] dex |
Rotation | 11.9 [7] days |
Age | 200±50 [7] Myr |
B | |
Mass | 0.28 –0.34 [2] M☉ |
C | |
Mass | 0.16 –0.24 [2] M☉ |
Orbit | |
Primary | A |
Companion | BC |
Period (P) | ≈80 [2] yr |
Orbit [6] | |
Primary | B |
Companion | C |
Period (P) | 36 yr |
Semi-major axis (a) | 444 mas (9.217 AU) [c] |
Eccentricity (e) | 0.136 |
Inclination (i) | 82.21° |
Argument of periastron (ω) (secondary) | 109.8° |
Position (relative to A) [2] | |
Epoch of observation | December 2006 |
Angular distance | 751 (A–B) 708 (A–C) 51 (B–C) mas |
Position angle | 342.5 (A–B) 344.7 (A–C) 130.3 (B–C)° |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
Gliese 900 (GJ 900, BD+00 5017) is a triple star system, located 68 light-years from Earth in the constellation Pisces. It is made up of three main sequence stars: one is a K-type star, the two others are M-dwarf stars. The two M-dwarfs form a binary system with a period of 36 years, and this system has a period of 80 years around the primary component. With an apparent magnitude of 9.546, Gliese 900 is not visible to the naked eye. A widely separated planet has been detected around the system. [7]
Gliese 900 is a hierarchical star system, made up of three main sequence stars: The primary component (Gliese 900 A) is a K5-K7 type star, that has 0.64–0.67 times the mass of the Sun, [2] 0.72 times its radius, [5] and 12% its luminosity. [4] A light curve from the Transiting Exoplanet Survey Satellite (TESS) shows that its rotational period is 12 days. [7] Gliese 900 A has a high level of chromospheric and coronal activity, although its apparent brightness presents little variation. [8] The other components are red dwarf stars. Gliese 900 B has a spectral type of M3–M4 and a mass between 0.24 and 0.34 solar masses. Gliese 900 C has a spectral type of M5–M6 and a mass between 0.16 and 0.24 solar masses. [2]
The system is young, about 200 million years old, and is a likely member (99.7% probability) of the nearby moving group Carina-Near. [9] It is a source of X-ray emission, with an observed flux of 9.13×102 mW M-2, and is also a source of ultraviolet emission. [7] The emission of X-rays is typical of young stars, and classifies it as one. [8] The TESS light curve identifies stellar flares on this star. [7]
Gliese 900 B and C form an inner pair (named Gliese 900 BC) with an orbital period of around 36 years. [6] Gliese 900 BC and Gliese 900 A orbit the system's center of mass with a period of 80 years. [2] [7] As of November 2004, [update] B was separated from A by 751 milliarcseconds and C was separated from A by 708 mas. This separation changes over time. [2] It was identified as a multiple star system in 2002 by Eduardo L. Martín, using adaptive optics-corrected images at the 8.2 m Subaru Telescope. When first observed, the A–B and A–C separations were of 0.51 and 0.76 arcsecs respectively. [8] A further study by Malogolovets et al. (2007) identified this system as a hierarchical triple. [2]
Malogolovets et al. (2007) reported two other objects in 2MASS images (potentially late red dwarfs) that would be the components D and E and make the system quintuple, being "very likely" to be bound to the system. [2] However, these faint stars haven't been confirmed as members of the GJ 900 system, and are likely not associated. [7]
Gliese 900 is located 68 light-years from Earth, based on parallax measurements by the Gaia spacecraft. [4] The BP-RP spectra suggest a distance of 67.7 ly. [4] The space velocity components of this system are U = −28.7, V = −15 and W = 0.2. [10] Gliese 900 is part of the thin disk population of the Milky Way. [10] [2] It was once classified as part of the IC 2602 supercluster. [8] A newer analysis using kinematics from the Gaia spacecraft suggest that Gliese 900 has a 99.7% chance of being a member of the Carina-Near moving group and a 0.3% chance of being a field star, i.e. not associated to any star cluster or stellar association. [7]
A 2024 study led by Austin Rothermich identified CWISE J233531.55+014219.6 (abbreviated to CW2335+0142) as a proper motion companion to Gliese 900, with 99.5% probability. [7] This object, also called Gliese 900 b or Gliese 900 (ABC)b, [11] [12] is a planetary-mass object that has 10.5 times the mass of Jupiter (0.01 times the mass of the Sun), a spectral type T9 [7] and a temperature of 500 K. [13] It was found to be at an angular separation of 587" from Gliese 900. At the estimated distance to this system, it translates to a projected separation of 12,000 astronomical units. [7]
As of 2024 [update] , Gliese 900 b has the largest observed separation of any known planet, and assuming a circular orbit, the longest orbital period. [14] [15] [d] The orbital period is estimated at 1.27 [16] million years based on the projected separation. Due to the similar spectral type, orbital separation and age, CW2335+0142 has been compared to COCONUTS-2b by the discovery team. [7]
Also in 2024, a study using data from the Wide-field Infrared Survey Explorer found a red W2-W3 color, which the researchers interpret as a sign of low gravity for T-dwarfs. Low gravity is often seen as an indicator of a young age and a low mass. [13]
Companion (in order from star) | Mass | Projected separation (AU) | Orbital period (106 years) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 10.5 MJ | 12,000 | 1.27 [16] | – | – | 1.11 RJ (estimate) [16] |