Astronomy:Mu2 Octantis
| Observation data {{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| Epoch J2000.0 [[Astronomy:Equinox (celestial coordinates)|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[1] mas/yr Dec.: −162.214[1] mas/yr |
| Parallax (π) | 25.0327 ± 0.0205[1] mas |
| 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 Dec.: −171.346 mas/yr |
| Parallax (π) | 25.0379 ± 0.0167[3] mas |
| 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 |
| 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 | 196067 data |
| Extrasolar Planets Encyclopaedia | 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
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 |♃|J}}}}}}, 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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Paunzen, E. (2015-08-01). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy and Astrophysics 580: A23. doi:10.1051/0004-6361/201526413. ISSN 0004-6361. Bibcode: 2015A&A...580A..23P.
- ↑ 3.0 3.1 3.2 3.3 3.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Marmier, M. et al. (2013). "The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets". Astronomy and Astrophysics 551: A90. doi:10.1051/0004-6361/201219639. Bibcode: 2013A&A...551A..90M.
- ↑ 5.0 5.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1.
- ↑ Gray, R. O. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc—The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 7.0 7.1 Flores, M; Yana Galarza, J; Miquelarena, P; Saffe, C; Jaque Arancibia, M; Ibañez Bustos, R V; Jofré, E; Alacoria, J et al. (2023-12-06). "Elemental abundance differences in the massive planet-hosting wide binary HD 196067−68". Monthly Notices of the Royal Astronomical Society 527 (4): 10016–10024. doi:10.1093/mnras/stad3714. ISSN 0035-8711.
- ↑ 8.0 8.1 8.2 8.3 8.4 Delisle, J.-B.; Faria, J. P.; Ségransan, D.; Fontanet, E.; Ceva, W.; Barbato, D.; Sousa, S. G.; Unger, N. et al. (2025-09-30). "Architecture of planetary systems with and without outer giant planets I. Inner planet detections around HD 23079, HD 196067, and HD 86226". Astronomy & Astrophysics.
- ↑ Li, Yiting; Brandt, Timothy D.; Brandt, G. Mirek; Dupuy, Trent J.; Michalik, Daniel; Jensen-Clem, Rebecca; Zeng, Yunlin; Faherty, Jacqueline et al. (2021). "Precise Masses and Orbits for Nine Radial-velocity Exoplanets". The Astronomical Journal 162 (6): 266. doi:10.3847/1538-3881/ac27ab. Bibcode: 2021AJ....162..266L.
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