Mu2 Octantis
Template:Other stars by Bayer designation
Template:Starbox observe 1s Template:Starbox observe 1s
  | |
| Characteristics | |
|---|---|
| μ2 Oct A | |
| Spectral type | G1V[1] |
| U−B color index | +0.26[2] |
| B−V color index | +0.62[2] |
| μ2 Oct B | |
| Spectral type | G1V[3] |
| Astrometry | |
| μ2 Oct A | |
| Radial velocity (Rv) | −11.00±0.12[4] km/s |
| Proper motion (μ) | RA: 156.404 mas/yr[4] Dec.: −162.214 mas/yr[4] |
| Parallax (π) | 25.0327±0.0205 mas[4] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 3.28[1] |
| μ2 Oct B | |
| Radial velocity (Rv) | −10.94±0.15[5] km/s |
| Proper motion (μ) | RA: +163.531 mas/yr[5] Dec.: −171.346 mas/yr[5] |
| Parallax (π) | 25.0379±0.0167 mas[5] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Orbit[1] | |
| Semi-major axis (a) | 932 AU |
| Details[6] | |
| μ2 Oct A | |
| Mass | 1.330±0.013 M☉ |
| Radius | 1.730+0.044 −0.039 R☉ |
| Luminosity | 3.54+0.27 −0.20[7] L☉ |
| Surface gravity (log g) | 4.09±0.02[7] cgs |
| Temperature | 6,059±52 K |
| Metallicity [Fe/H] | +0.216±0.009 dex |
| Rotation | 22.5±2.9[7] days |
| Rotational velocity (v sin i) | 1.45[1] 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: Template:Odlist | |
| μ2 Oct B: Template:Odlist | |
| 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.[8] Based on parallax measurements, it lies 130.3 light-years away.[4][5]
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.[1]
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.[6]
Planetary system
From 1998 to 2012, the system was observed using the CORALIE instrument, at the ESO's La Silla Observatory.[1]
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.[7]
| 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
Page Template:Reflist/styles.css has no content.
- ^ a b c d e f Page Module:Citation/CS1/styles.css has no content.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. arXiv:1211.6444. Bibcode:2013A&A...551A..90M. doi:10.1051/0004-6361/201219639. S2CID 59467665.
- ^ a b Page Module:Citation/CS1/styles.css has no content.Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ Page Module:Citation/CS1/styles.css has no content.Gray, R. O.; et al. (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. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
- ^ a b c d Template:Cite Gaia DR3
- ^ a b c d Template:Cite Gaia DR3
- ^ a b Page Module:Citation/CS1/styles.css has no content.Flores, M; Yana Galarza, J; Miquelarena, P; Saffe, C; Jaque Arancibia, M; Ibañez Bustos, R V; Jofré, E; Alacoria, J; Gunella, F (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. arXiv:2311.17272. doi:10.1093/mnras/stad3714. ISSN 0035-8711.
- ^ a b c d e Page Module:Citation/CS1/styles.css has no content.Delisle, J.-B.; Faria, J. P.; Ségransan, D.; Fontanet, E.; Ceva, W.; Barbato, D.; Sousa, S. G.; Unger, N.; Leleu, A. (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. arXiv:2509.26232.
- ^ Page Module:Citation/CS1/styles.css has no content.Paunzen, E. (2015-08-01). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy and Astrophysics. 580: A23. arXiv:1506.04568. Bibcode:2015A&A...580A..23P. doi:10.1051/0004-6361/201526413. ISSN 0004-6361.
- ^ Page Module:Citation/CS1/styles.css has no content.Li, Yiting; Brandt, Timothy D.; Brandt, G. Mirek; Dupuy, Trent J.; Michalik, Daniel; Jensen-Clem, Rebecca; Zeng, Yunlin; Faherty, Jacqueline; Mitra, Elena L. (2021). "Precise Masses and Orbits for Nine Radial-velocity Exoplanets". The Astronomical Journal. 162 (6): 266. arXiv:2109.10422. Bibcode:2021AJ....162..266L. doi:10.3847/1538-3881/ac27ab. S2CID 237592581.
