Astronomy:Gliese 758

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Short description: Star in the constellation Lyra
Gliese 758
GJ 758 System - Labeled.jpg
Discovery image of Gliese 758 B, taken with Subaru HiCIAO in the near infrared
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lyra
Right ascension  19h 23m 34.013166s[1]
Declination +33° 13′ 19.078368″[1]
Apparent magnitude (V) 6.36[2]
Characteristics
Spectral type G8V[3]+T8[4]
U−B color index +0.455[2]
B−V color index +0.799[2]
Astrometry
Radial velocity (Rv)−21.62±0.12[1] km/s
Proper motion (μ) RA: 81.966±0.013[1] mas/yr
Dec.: 160.158±0.016[1] mas/yr
Parallax (π)64.0703 ± 0.0154[1] mas
Distance50.91 ± 0.01 ly
(15.608 ± 0.004 pc)
Absolute magnitude (MV)5.37[5]
Orbit[6]
PrimaryGliese 758 A
CompanionGliese 758 B
Period (P)131.276+15.078
−12.080 yr
Semi-major axis (a)25.409+1.944
−1.626 astronomical unit|AU
Eccentricity (e)0.365+0.079
−0.082
Inclination (i)38.080+5.438
−4.808°
Longitude of the node (Ω)349.680+5.776
−6.263°
Periastron epoch (T)2,421,289.845+3,708.120
−4,680.545
Argument of periastron (ω)
(secondary)		175.102+11.951
−14.709°
Semi-amplitude (K1)
(primary)		0.139318+0.009603
−0.008036 km/s
Details
Gliese 758 A
Mass0.93±0.03[6] M☉
Radius0.88[7] R☉
Surface gravity (log g)4.55[7] cgs
Temperature5305[1] K
Metallicity [Fe/H]0.18[3] dex
Age7.7–8.7[8] Gyr
Gliese 758 B
Mass36.387+1.210
−1.081[6] MJup
Temperature600±100[4] K
Other designations
GJ 758, BD+32 3411, HD 182488, HIP 95319, HR 7368, PPM 82821, SAO 68239[9]
Database references
SIMBADA
B
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 50.9 light-years (15.6 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]

Companion

In November 2009, a team using the HiCIAO instrument of the Subaru Telescope imaged a substellar companion orbiting the star. This brown dwarf, 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][12] Follow-up studies of the system refined 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.[13] On the other hand, a younger age was suggested from the kinematic stellar grouping.

The most recent parameters for Gliese 758 B as of 2022 come from a combination of data from radial velocity, astrometry, and imaging,[14][15][6] showing that it is about 36 times the mass of Jupiter, and on an eccentric orbit with a semi-major axis of about 25.4 astronomical units and an orbital period of about 131 years.[6]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 Breger, M. (March 1968), "UBV and narrow-band UVBY photometry of bright stars", Astronomical Journal 73: 84–85, doi:10.1086/110602, Bibcode: 1968AJ.....73...84B 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 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. doi:10.1051/0004-6361:20078788. Bibcode: 2008A&A...480...91S. 
  4. ↑ 4.0 4.1 Vigan, A.; Bonnefoy, M.; Ginski, C.; Beust, H.; Galicher, R.; Janson, M.; Baudino, J.-L.; Buenzli, E. et al. (16 February 2016). "First light of the VLT planet finder SPHERE". Astronomy & Astrophysics 587: A55. doi:10.1051/0004-6361/201526465. Bibcode: 2016A&A...587A..55V. 
  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, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Feng, Fabo et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series 262 (21): 21. doi:10.3847/1538-4365/ac7e57. Bibcode: 2022ApJS..262...21F. 
  7. ↑ 7.0 7.1 7.2 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, doi:10.1086/509763, Bibcode: 2007ApJS..168..297T 
  8. ↑ 8.0 8.1 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, doi:10.1086/591785, Bibcode: 2008ApJ...687.1264M 
  9. ↑ "HD 182488". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+182488. 
  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, doi:10.1088/0004-637X/707/2/L123, Bibcode: 2009ApJ...707L.123T 
  11. ↑ "Possible Planet Around a G-class Star". Centauri Dreams. 2009-12-04. http://www.centauri-dreams.org/?p=10517. 
  12. ↑ "Discovery of an Exoplanet Candidate Orbiting a Sun-Like Star: Inaugural Observations with Subaru's New Instrument HiCIAO", Subaru Telescope, 2009-12-03, http://subarutelescope.org/Pressrelease/2009/12/03/index.html, retrieved 2009-12-04 
  13. ↑ Janson, M.; Carson, J.; Thalmann, C.; McElwain, M. W.; Goto, M.; Crepp, J.; Wisniewski, J.; Abe, L. et al. (2011), "Near-infrared Multi-band Photometry of the Substellar Companion GJ 758 B", The Astrophysical Journal 728 (2): 85, doi:10.1088/0004-637X/728/2/85, Bibcode: 2011ApJ...728...85J 
  14. ↑ Bowler, Brendan P. et al. (2018). "Orbit and Dynamical Mass of the Late-T Dwarf GL 758 B". The Astronomical Journal 155 (4): 159. doi:10.3847/1538-3881/aab2a6. Bibcode: 2018AJ....155..159B. 
  15. ↑ Brandt, G. Mirek et al. (December 2021). "Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3". The Astronomical Journal 162 (6): 301. doi:10.3847/1538-3881/ac273e. Bibcode: 2021AJ....162..301B. 

External links

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



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