HD 136164

Last updated
HD 136164
Observation data
Epoch J2000       Equinox J2000
Constellation Lupus [1]
Right ascension 15h 20m 13.3930s [2]
Declination −34° 55′ 31.574″ [2]
Apparent magnitude  (V)+7.76±0.01 [3]
Characteristics
Spectral type A2V (A) [4]
M6-L2 (Ab) [5]
B−V color index 0.175±0.015 [1]
Astrometry
Proper motion (μ)RA: −22.631 mas/yr [2]
Dec.: −25.861 mas/yr [2]
Parallax (π)8.2024±0.0401  mas [2]
Distance 398 ± 2  ly
(121.9 ± 0.6  pc)
Absolute magnitude  (MV)+2.05 [1]
Position (relative to A) [5]
ComponentB
Angular distance 5.159±0.003 ″
Position angle 33.0±0.2°
Projected separation 650 AU
Orbit [6]
PrimaryA
CompanionAb
Period (P)130 [5]   yr
Semi-major axis (a)22.48+1.15
−1.03  au
Eccentricity (e)0.44±0.03
Inclination (i)11.5+4.6
−5.2°
Longitude of the node (Ω)75+27
−25°
Periastron epoch (T)2023.67+0.36
−0.21
Argument of periastron (ω)
(secondary)		128+25
−30°
Details
A
Mass 1.87±0.07 [6]   M☉
Radius 1.66+0.13
−0.15 [7]   R☉
Luminosity 12.65 [1]   L☉
Surface gravity (log g)4.2 [6]   cgs
Temperature 8,100 [6]   K
Metallicity [Fe/H]−0.07+0.11
−0.13 [7]   dex
Age 16±2 [6]   Myr
Ab
Mass 35±10 [6]   MJup
Radius 1.9 [6]   RJup
Luminosity2.09+0.42
−0.23×10−3 [6]   L☉
Surface gravity (log g)4.35 [6]   cgs
Temperature 2,640 [6]   K
Metallicity [Fe/H]+0.39 [6]   dex
Age 16±2 [6]   Myr
B
Mass 0.30 [8]   M☉
Age 16±2 [6]   Myr
Other designations
CD−34°10322, HD 136164, HIP 75056, TYC 7321-201-1 [9]
Database references
SIMBAD data

HD 136164, also known as HIP 75056, is a binary star system in the constellation Lupus. At an apparent magnitude of +7.76, it is far too faint to be visible to the naked eye. Parallax measurements give a distance of 398 light-years (121.9 parsecs ). The primary is orbited by a brown dwarf.

Contents

Characteristics

This is a visual binary system whose components, as of 2015, are separated by 5.195" in the sky, translating to a projected separation of 650  astronomical units. The orbital period is estimated at 8,000 years. [5] The system is 16 million years old and is part of the Upper–Centaurus–Lupus stellar association. [6]

The primary component, HD 136164 A, has a spectrum matching a spectral class of A2V, [4] with the luminosity class 'V' indicating it is a main sequence star fusing atoms of hydrogen into helium at its core. The star has 1.87 times the mass [6] and 1.66 times the radius of the Sun. [7] It radiates 12.65 times the Sun's luminosity from its photosphere [1] at an effective temperature of 8,100  K . [6] This temperature gives it the white hue typical of an A-type stars. [10]

The secondary has a mass of 0.30 M☉. [8]

Substellar companion

The primary star is orbited by a brown dwarf named HD 136164 Ab or HIP 75056 Ab. It was first discovered in 2020 through direct imaging. [5] The companion orbits at a semi-major axis of 22.5  astronomical units, has a mild eccentricity, [6] and takes roughly 130 years to circle the host star. [5] Relative to Earth, the orbit is nearly face-on, with an inclination less than 35°. [6]

Based on observations of the brown dwarf's orbit using both relative and absolute astrometry, its mass is measured at 35±10  Jupiter masses . Comparing its spectrum to atmospheric models retrieve a radius of 1.9 RJ and an effective temperature of 2,640  K . The luminosity is estimated at 10−2.68+0.08
−0.05 L☉ from evolutionary models. The carbon-to-oxygen abundance ratio and relatively high eccentricity of the orbit suggest that the companion formed like a failed star, either via fragmentation of the circumstellar disk or via fragmentation of a molecular cloud. [6]

References

  1. 1 2 3 4 5 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 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.
  3. ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 –L30. Bibcode:2000A&A...355L..27H. ISSN   0004-6361.
  4. 1 2 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0. Bibcode:1982mcts.book.....H.
  5. 1 2 3 4 5 6 Wagner, Kevin; Apai, Dániel; Kasper, Markus; McClure, Melissa; Robberto, Massimo; Currie, Thayne (2020-10-01). "Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star". The Astrophysical Journal Letters. 902 (1): L6. Bibcode:2020ApJ...902L...6W. doi: 10.3847/2041-8213/abb94e . ISSN   2041-8205.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 =Balmer, William O.; Pueyo, L.; Lacour, S.; Wang, J. J.; Stolker, T.; Kammerer, J.; Pourré, N.; Nowak, M.; Rickman, E.; Blunt, S.; Sivaramakrishnan, A.; Sing, D.; Wagner, K.; Marleau, G.-D.; Lagrange, A.-M. (2024-02-01). "VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab Formed Like a "Failed Star"". The Astronomical Journal. 167 (2): 64. Bibcode:2024AJ....167...64B. doi: 10.3847/1538-3881/ad1689 . ISSN   0004-6256.
  7. 1 2 3 Bochanski, John J.; Faherty, Jacqueline K.; Gagné, Jonathan; Nelson, Olivia; Coker, Kristina; Smithka, Iliya; Desir, Deion; Vasquez, Chelsea (April 2018). "Fundamental Properties of Co-moving Stars Observed by Gaia". The Astronomical Journal. 155 (4): 149. arXiv: 1801.00537 . Bibcode:2018AJ....155..149B. doi: 10.3847/1538-3881/aaaebe . ISSN   0004-6256.
  8. 1 2 Kouwenhoven, M. B. N.; Brown, A. G. A.; Portegies Zwart, S. F.; Kaper, L. (October 2007). "The primordial binary population. II.: Recovering the binary population for intermediate mass stars in Scorpius OB2". Astronomy & Astrophysics. 474 (1): 77–104. Bibcode:2007A&A...474...77K. doi:10.1051/0004-6361:20077719. ISSN   0004-6361.
  9. ↑ "HIP 75056". SIMBAD . Centre de données astronomiques de Strasbourg.
  10. ↑ "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.
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