Gliese 758

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Gliese 758
GJ 758 System - Labeled.jpg
Discovery image of Gliese 758 b, taken with Subaru HiCIAO in the near infrared
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 19h 23m 34.01358s[1]
Declination +33° 13′ 19.0725″[1]
Apparent magnitude (V) 6.36[2]
Characteristics
Spectral type G8V[3]
U−B color index +0.455[2]
B−V color index +0.799[2]
Astrometry
Radial velocity (Rv)-21.6[4] km/s
Proper motion (μ) RA: 81.80[4] mas/yr
Dec.: 160.39[4] mas/yr
Parallax (π)64.06 ± 0.02[4] mas
Distance50.91 ± 0.02 ly
(15.610 ± 0.005 pc)
Absolute magnitude (MV)5.37[5]
Orbit[6]
PrimaryGliese 758 A
CompanionGliese 758 B
Period (P)96+21
−9 yr
Semi-major axis (a)21.1+2.7
−1.3 AU
Eccentricity (e)0.58+0.07
−0.11
Inclination (i)28+12
−10°
Longitude of the node (Ω)175±5°
Periastron epoch (T)2,465,800+2,000
−800
Argument of periastron (ω)
(secondary)		184+8
−9°
Details
Mass0.966[7] M☉
Radius0.88[7] R☉
Surface gravity (log g)4.55[7] cgs
Temperature5404[4] K
Metallicity [Fe/H]0.18[3] dex
Age7.7–8.7[8] Gyr
Other designations
GJ 758, BD+32 3411, HD 182488, HIP 95319, HR 7368, PPM 82821, SAO 68239[9]
Database references
SIMBADdata
Extrasolar Planets
Encyclopaedia		data

Gliese 758 is a star in the northern constellation of Lyra. At about magnitude 6 it is a challenge to view with the naked eye even in good seeing conditions, but can be easily seen through a small telescope or binoculars. Parallax measurements from the Hipparcos mission give it an estimated distance of around 51.4 light-years (15.8 parsecs) from Earth.

Properties[]

This is a Sun-like star with 97% of the Sun's mass and 88% of the radius of the Sun. The spectrum matches a stellar classification of G8V,[3] identifying it as a G-type main-sequence star that is generating energy through the nuclear fusion of hydrogen at its core. It is radiating this energy into space from its outer envelope at an effective temperature of 5,425 K.[3] Estimates of its age put it at about 7.7–8.7 billion years old,[8] although some measurements give it an age as low as 720 million years.[7] The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, are 51% higher than in the Sun.[3]

System[]

In November 2009, a team using the HiCIAO instrument of the Subaru Telescope imaged a substellar companion orbiting the star. This object, designated Gliese 758 B, was estimated to be of approximately 10 to 40 Jupiter masses. A second candidate object was also detected, which was given the designation Gliese 758 C.[10][11] Follow-up studies of the system suggested the mass range of Gliese 758 B, indicating it to be a companion with approximately 30 to 40 Jupiter masses and revealed that Gliese 758 C is a background star which is not physically associated with the Gliese 758 system.[12] On the other hand, a younger age was suggested from the kinematic stellar grouping.

Orbit[]

Gliese 758 B is on an eccentric orbit with a semi-major axis of 21.1+2.7
−1.3 astronomical units and an orbital period of 96+21
−9 years, which takes it within nine astronomical units of its host star at its closest approach.[6]

See also[]

References[]

  1. ^ a b van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. ^ a b c Breger, M. (March 1968), "UBV and narrow-band UVBY photometry of bright stars", Astronomical Journal, 73: 84–85, Bibcode:1968AJ.....73...84B, doi:10.1086/110602
  3. ^ a b c d e Soubiran, C.; et al. (2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics. 480 (1): 91–101. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. S2CID 16602121.
  4. ^ a b c d e Gaia Collaboration; et al. (2018), "Gaia Data Release 2.", Astronomy and Astrophysics, 616 (Special Issue): A1, arXiv:1804.09365v2, doi:10.1051/0004-6361/201833051, S2CID 49211658
  5. ^ Holmberg, J.; Nordström, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511
  6. ^ a b Bowler, Brendan P.; et al. (2018). "Orbit and Dynamical Mass of the Late-T Dwarf GL 758 B". The Astronomical Journal. 155 (4): 159. arXiv:1802.10126. Bibcode:2018AJ....155..159B. doi:10.3847/1538-3881/aab2a6. S2CID 54816662.
  7. ^ a b c d Takeda, Genya; et al. (February 2007), "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog", The Astrophysical Journal Supplement Series, 168 (2): 297–318, arXiv:astro-ph/0607235, Bibcode:2007ApJS..168..297T, doi:10.1086/509763, S2CID 18775378
  8. ^ a b Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785, S2CID 27151456
  9. ^ "HD 182488". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2009-12-13.
  10. ^ Thalmann, C.; et al. (2009), "Discovery of the Coldest Imaged Companion of a Sun-Like Star", The Astrophysical Journal Letters, 707 (2): L123–L127, arXiv:0911.1127, Bibcode:2009ApJ...707L.123T, doi:10.1088/0004-637X/707/2/L123, S2CID 116823073
  11. ^ "Discovery of an Exoplanet Candidate Orbiting a Sun-Like Star: Inaugural Observations with Subaru's New Instrument HiCIAO", Subaru Telescope, 2009-12-03, retrieved 2009-12-04
  12. ^ Janson, M.; Carson, J.; Thalmann, C.; McElwain, M. W.; Goto, M.; Crepp, J.; Wisniewski, J.; Abe, L.; Brandner, W.; Burrows, Adam; Egner, S.; Feldt, M.; Grady, C. A.; Golota, T.; Guyon, Olivier; Hashimoto, J.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K. W.; Ishii, M.; Iye, M.; Kandori, R.; Knapp, G. R.; Kudo, T.; Kusakabe, N.; Kuzuhara, M.; Matsuo, T.; Mayama, S.; Miyama, S.; Morino, J.-I.; Moro-Martín, A.; Nishimura, T.; Pyo, T.-S.; Serabyn, E.; Suto, H.; Suzuki, R.; Takami, M.; Takato, N.; Terada, H.; Tofflemire, B.; Tomono, D.; Turner, E. L.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M. (2011), "Near-infrared Multi-band Photometry of the Substellar Companion GJ 758 B", The Astrophysical Journal, 728 (2): 85, arXiv:1011.5505, Bibcode:2011ApJ...728...85J, doi:10.1088/0004-637X/728/2/85, S2CID 119296265

External links[]

Coordinates: Sky map 19h 23m 34.0s, +33° 13′ 19.1″

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