Mu2 Octantis
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Octans |
| μ2 Oct A | |
| Right ascension | 20h 41m 44.1016s[1] |
| Declination | −75° 21′ 02.883″[1] |
| Apparent magnitude (V) | +6.481±0.007[2] |
| μ2 Oct B | |
| Right ascension | 20h 41m 45.5181s[3] |
| Declination | −75° 20′ 47.047″[3] |
| Apparent magnitude (V) | +7.153±0.011[2] |
| Characteristics | |
| μ2 Oct A | |
| Spectral type | G1V[4] |
| U−B color index | +0.26[5] |
| B−V color index | +0.62[5] |
| μ2 Oct B | |
| Spectral type | G1V[6] |
| Astrometry | |
| μ2 Oct A | |
| Radial velocity (Rv) | −11.00±0.12[1] km/s |
| Proper motion (μ) | RA: 156.404 mas/yr[1] Dec.: −162.214 mas/yr[1] |
| Parallax (π) | 25.0327±0.0205 mas[1] |
| Distance | 130.3 ± 0.1 ly (39.95 ± 0.03 pc) |
| Absolute magnitude (MV) | 3.28[4] |
| μ2 Oct B | |
| Radial velocity (Rv) | −10.94±0.15[3] km/s |
| Proper motion (μ) | RA: +163.531 mas/yr[3] Dec.: −171.346 mas/yr[3] |
| Parallax (π) | 25.0379±0.0167 mas[3] |
| Distance | 130.27 ± 0.09 ly (39.94 ± 0.03 pc) |
| Orbit[4] | |
| Semi-major axis (a) | 932 AU |
| Details[7] | |
| μ2 Oct A | |
| Mass | 1.330±0.013 M☉ |
| Radius | 1.730+0.044 −0.039 R☉ |
| Luminosity | 3.54+0.27 −0.20[8] L☉ |
| Surface gravity (log g) | 4.09±0.02[8] cgs |
| Temperature | 6,059±52 K |
| Metallicity [Fe/H] | +0.216±0.009 dex |
| Rotation | 22.5±2.9[8] days |
| Rotational velocity (v sin i) | 1.45[4] km/s |
| Age | 3.50+0.65 −0.27 Gyr |
| μ2 Oct B | |
| Mass | 1.190+0.017 −0.018 M☉ |
| Radius | 1.190+0.034 −0.010 R☉ |
| Temperature | 6,020±52 K |
| Metallicity [Fe/H] | +0.267±0.009 dex |
| Age | 2.10+1.03 −0.34 Gyr |
| Other designations | |
| μ2 Oct, CCDM J20417-7521 | |
| μ2 Oct A: CD−75°1173, HD 196067, HIP 102125, HR 7864, SAO 257836, 2MASS J20414409-7521029 | |
| μ2 Oct B: CD−75°1174, HD 196068, HIP 102128, SAO 257837, 2MASS J20414550-7520471 | |
| Database references | |
| SIMBAD | A |
| B | |
| Exoplanet Archive | data |
Mu2 Octantis (μ2 Oct) is a binary star system in the constellation Octans, whose primary and secondary stars have apparent magnitudes of +6.481 and 7.153, respectively.[2] Based on parallax measurements, it lies 130.3 light-years away.[1][3]
The two stars, HD 196067 and HD 196068 (also named μ2 Oct A and μ2 Oct B), are separated at 17 arcseconds in the sky, corresponding to 740 astronomical units (AU). The semimajor axis of the stars' orbit is 932 AU.[4]
Component A is a G-dwarf star with 1.33 and 1.73 times of the Sun's mass and radius, respectively. Component B also a G-type main-sequence star with a radius 1.19 times larger than the Sun. Their effective temperatures are similar. HD 196068 has a higher metallicity than its companion, the reasons for this are uncertain.[7]
Planetary system
[edit | edit source]From 1998 to 2012, the system was observed using the CORALIE instrument, at the ESO's La Silla Observatory.[4]
In November 2012, a long-period, wide-orbiting planet was deduced by radial velocity around HD 196067. The planet has been pulled to an eccentric orbit by the B star HD 196068. The planet's true mass, as measured by astrometry, is 12.5 MJ, placing it right on the traditionally adopted boundary between planets and brown dwarfs.[9]
A second, innermost planet was detected using radial velocity observations with the CORALIE, HARPS, and ESPRESSO observatories. Despite its small orbit, it does not transit the host star.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | ≥10.4±1.39 M🜨 | — | 4.601088±0.000192 | 0.235±0.118 | — | — |
| b | 11.4±1.6 MJ | 4.71+0.11 −0.10 |
3,413.7±10.5 | 0.56292±0.00703 | 29.7+5.0 −3.8° |
— |
References
[edit | edit source]- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
