HD 134606
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 15h 15m 15.04464s[1]
Declination −70° 31′ 10.6449″[1]
Apparent magnitude (V) 6.86[2]
Characteristics
Spectral type G6 IV[3]
B−V color index 0.740±0.001[2]
Astrometry
Radial velocity (Rv)+1.94±0.12[1] km/s
Proper motion (μ) RA: −177.871 mas/yr[1]
Dec.: −164.709 mas/yr[1]
Parallax (π)37.3020 ± 0.0182 mas[1]
Distance87.44 ± 0.04 ly
(26.81 ± 0.01 pc)
Absolute magnitude (MV)4.74[2]
Details[4]
Mass1.046+0.070
−0.059 M☉
Radius1.158+0.039
−0.036 R☉
Luminosity1.161+0.071
−0.049 L☉
Surface gravity (log g)4.330+0.044
−0.041 cgs
Temperature5,576+86
−85 K
Metallicity [Fe/H]+0.343+0.081
−0.084 dex
Rotation42.0±3.9 d
Age7.3+3.6
−3.4 Gyr
Other designations
CD−70° 1258, GC 20455, HD 134606, HIP 74653, SAO 257257, LTT 6064, 2MASS J15151504-7031105[5]
Database references
SIMBADdata

HD 134606 is a yellow-hued star with a planetary system, positioned in the southern constellation of Apus. It is below the nominal limit for visibility with the naked eye, having an apparent visual magnitude of 6.86.[2] Based upon an annual parallax shift of 37.3 mas, it is located 87.44 light-years away. The star appears to be moving further from the Earth with a heliocentric radial velocity of +1.9 km/s.[1]

This is an evolving G-type subgiant star with a stellar classification of G6 IV[3] and is not considered active, having a chromospheric activity index of −5.04.[6] It has about the same[7] mass as the Sun but is 25% more luminous.[2] The photosphere is radiating energy at an effective temperature of 5,614 K.[7] It has a higher than solar metallicity – a term astronomers use to describe the abundance of elements other than hydrogen and helium.[7]

There is a red dwarf companion star of spectral type M3V at a separation of ~1500 AU, designated L 72-1.[8][4]

Planetary system

The discovery of a planetary system orbiting HD 134606 was announced in 2011 following an eight-year survey carried out at the La Silla Observatory in Chile. The detection was made via the radial velocity method using the HARPS instrument. Applying a Keplerian fit to the data suggests the presence of three planets in moderately eccentric orbits.[9] None of the planetary orbits displays a mean motion resonance with the others.[10]

The system was updated by a 2024 study, which confirmed the three previously reported planets, though with a longer period for planet d, and detected two new ones. While all five planets are very likely to be real, the study advises caution regarding planet f due to the similarity of its period to the lunar cycle. The five planets range from super-Earth to super-Neptune mass, and the outermost, HD 134606 d, is a small gas giant orbiting within the habitable zone that may be a candidate for future space-based direct imaging missions. A long-period radial velocity trend was also detected, suggesting the presence of a distant sixth substellar companion of some kind.[4]

The HD 134606 planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
e ≥2.34+0.35
−0.34 M🜨 		0.0527+0.0011
−0.0012 		4.3203+0.00051
−0.00047 		0.2+0.14
−0.13 		— —
b ≥9.09+0.64
−0.63 M🜨 		0.1046+0.0023
−0.0024 		12.089+0.0016
−0.0015 		0.092+0.054
−0.053 		— —
f ≥5.63+0.72
−0.69 M🜨 		0.1784+0.0039
−0.0041 		26.915±0.016 0.081+0.1
−0.059 		— —
c ≥11.31+1.0
−0.99 M🜨 		0.3007+0.0066
−0.0069 		58.883+0.041
−0.039 		0.055+0.062
−0.04 		— —
d ≥44.8±2.9 M🜨 1.941+0.043
−0.046 		966.5+5.3
−6.9 		0.092±0.045 — —

References

  1. ^ 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.
  2. ^ a b c d e Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. ^ a b Gray, R. O.; et al. (July 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.
  4. ^ a b c d Li, Zhexing; Kane, Stephen R.; Brandt, Timothy D.; Fetherolf, Tara; Robertson, Paul; Zhao, Jinglin; Dalba, Paul A.; Wittenmyer, Robert A.; Butler, R. Paul (January 2024). "Revised Architecture and Two New Super-Earths in the HD 134606 Planetary System". The Astronomical Journal. arXiv:2401.17415.
  5. ^ "HD 134606". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 20, 2018.
  6. ^ Jenkins, J. S.; et al. (October 2006), "An activity catalogue of southern stars", Monthly Notices of the Royal Astronomical Society, 372 (1): 163–173, arXiv:astro-ph/0607336, Bibcode:2006MNRAS.372..163J, doi:10.1111/j.1365-2966.2006.10811.x, S2CID 17524675.
  7. ^ a b c Tsantaki, M.; et al. (July 2013). "Deriving precise parameters for cool solar-type stars. Optimizing the iron line list". Astronomy & Astrophysics. 555: A150. arXiv:1304.6639. Bibcode:2013A&A...555A.150T. doi:10.1051/0004-6361/201321103. S2CID 118388752.
  8. ^ "L 72-1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 February 2024.
  9. ^ Mayor, M.; Marmier, M.; Lovis, C.; Udry, S.; Ségransan, D.; Pepe, F.; Benz, W.; Bertaux, J.-L.; Bouchy, F.; Dumusque, X.; Lo Curto, G.; Mordasini, C.; Queloz, D.; Santos, N. C. (September 13, 2011), The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets, arXiv:1109.2497
  10. ^ Giuppone, C. A.; et al. (December 2013), "A semi-empirical stability criterion for real planetary systems with eccentric orbits", Monthly Notices of the Royal Astronomical Society, 436 (4): 3547–3556, arXiv:1309.6861, Bibcode:2013MNRAS.436.3547G, doi:10.1093/mnras/stt1831
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