Mu2 Octantis
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Octans |
| μ2 Oct A | |
| Right ascension | 20h 41m 44.102s[1] |
| Declination | −75° 21′ 02.88″[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) | −10.90±0.2[7] 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[8] | |
| μ2 Oct A | |
| Mass | 1.330±0.013 M☉ |
| Radius | 1.730+0.044 −0.039 R☉ |
| Luminosity | 3.73[4] L☉ |
| Surface gravity (log g) | 4.24±0.03[4] cgs |
| Temperature | 6,059±52 K |
| Metallicity [Fe/H] | +0.216±0.009 dex |
| Rotation | 26±3[4] 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☉ |
| 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 | |
| A | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Database references | |
| B | |
| SIMBAD | 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.[8]
Planetary system
[edit]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 boundary between planets and brown dwarfs.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 12.5+2.5 −1.8 MJ |
5.10+0.22 −0.17 |
9.88+0.63 −0.43 |
0.70+0.14 −0.12 |
41.2+28 −9.1° |
— |
References
[edit]- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c 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.
- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g h i 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 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ 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.
- ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b 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 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.
