Groombridge 34

Groombridge 34 or ADS 246 A or Gliese 15 00h18m22.89s, +44°01'22.6"
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 18m 22.89s[1]
Declination +44° 01′ 22.6″[1]
Apparent magnitude (V) 8.09/11.06
Characteristics
Spectral type M1.5V + M3.5V
U−B color index 1.24
B−V color index 1.56
Variable type Flare stars
Astrometry
Radial velocity (Rv)+12.0 km/s
Proper motion (μ) RA: +2888.92 ± 0.60[1] mas/yr
Dec.: +410.10 ± 0.48[1] mas/yr
Parallax (π)278.76 ± 0.77[1] mas
Distance11.70 ± 0.03 ly
(3.587 ± 0.010 pc)
Absolute magnitude (MV)10.32/13.29
Orbit
CompanionGroombridge 34 B
Gl 15 B
Period (P)2,600 yr
Semi-major axis (a)41.15"
Eccentricity (e)0.00
Inclination (i)61.4°
Longitude of the node (Ω)45.3°
Periastron epoch (T)1745
Details
GX And
Mass0.404[2] M☉
Radius0.3863 ± 0.0021[3] R☉
Luminosity (bolometric)0.02589[note 1] L☉
Luminosity (visual, LV)0.00637[note 2] L☉
Surface gravity (log g)4.89[2] cgs
Temperature3,730 ± 49[2] K
Metallicity [Fe/H]-0.32 dex
GQ And
Mass0.163 M☉
Radius0.19 R☉
Luminosity (bolometric)~0.00262[note 1] L☉
Luminosity (visual, LV)0.00041[note 2] L☉
Temperature~3,000 K
Other designations
GX/GQ Andromedae, BD +43°44, GCTP 49, GJ 15 A/B, Gl 171-047/171-048, HD 1326, HIP 1475, LHS 3/4, LTT 10108/10109, LFT 31/32, SAO 36248, Vys 085 A/B.
Database references
SIMBADdata
Database references
SIMBADdata

Groombridge 34 is a binary star system located about 11.7 light-years from the Sun. It consists of two red dwarfs in a nearly circular orbit with a separation of about 147 AU. Both stars in this pair exhibit variability due to random flares and they have been given variable star designations. (The brighter member Groombridge 34 A is designated GX And, and the other member is designated GQ And).

Distance

Groombridge 34 distance estimates

Source Parallax, mas Distance, pc Distance, ly Distance, Pm Ref.
Woolley et al. (1970) 282±7 3.55±0.09 11.57+0.29
−0.28		 109.4+2.8
−2.7		 [4]
Gliese & Jahreiß (1991) 289.5±4.9 3.45±0.06 11.27±0.19 106.6±1.8 [5]
van Altena et al. (1995) 282.0±2.2 3.546+0.028
−0.027		 11.57±0.09 109.4+0.9
−0.8		 [6]
Perryman et al. (1997) (Hipparcos) 280.27±1.05 3.568±0.013 11.64±0.04 110.1±0.4 [7]
Perryman et al. (1997) (Tycho) 320.70±24.40 3.12+0.26
−0.22		 10.2+0.8
−0.7		 96.2+7.9
−6.8		 [8]
van Leeuwen (2007) 278.76±0.77 3.587±0.01 11.7±0.03 110.69+0.31
−0.3		 [1]
Gatewood (2008) (MAP-based study) 281.45±1.05 3.553±0.013 11.59±0.04 109.6±0.4 [9]
RECONS TOP100 (2012) 279.87±0.60[note 3] 3.573±0.008 11.654±0.025 110.25±0.24 [10]
Dittmann et al. (2014) (A) 279.30±5.40 3.58±0.07 11.68+0.23
−0.22		 110.5+2.2
−2.1		 [11]
Dittmann et al. (2014) (B) 313.90±9.30 3.19+0.1
−0.09		 10.39+0.32
−0.3		 98.3+3
−2.8		 [11]

Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.

Planetary system

In August 2014, a planet orbiting around Groombridge 34 A was reported.[3] The planet's existence was deduced from analysis of the radial velocities of the parent Star by the Eta-Earth Survey using HIRES at Keck Observatory.

The planet is thought to have a minimum mass of 5.35 ± 0.75 Earth masses,[12] and at its discovery was the sixth nearest known exoplanet.

The Groombridge 34 A planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥ 5.35±0.75 M⊕ 0.0717±0.0034 11.4433±0.0017 0.12? — —

See also

Notes

  1. ↑ 1.0 1.1 From \begin{smallmatrix}L=4 \pi R^2 \sigma T_{\rm eff}^4 \end{smallmatrix}, where \begin{smallmatrix}L \end{smallmatrix} is the luminosity, \begin{smallmatrix}R \end{smallmatrix} is the radius, \begin{smallmatrix}T_{\rm eff}\end{smallmatrix} is the effective surface temperature and \begin{smallmatrix}\sigma \end{smallmatrix} is the Stefan–Boltzmann constant
  2. ↑ 2.0 2.1 Using the absolute visual magnitude of Gliese 15 A, \scriptstyle M_{V_{\ast}}=10.32, and Gliese 15 B, \scriptstyle M_{V_{\ast}}=13.29, with the absolute visual magnitude of the Sun, \scriptstyle M_{V_{\odot}}=4.83, the two visual luminosities of the stars can be calculated by \scriptstyle \frac{L_{V_{\ast}}}{L_{V_{\odot}}}=10^{0.4\left(M_{V_{\odot}} - M_{V_{\ast}}\right)}
  3. ↑ Weighted parallax based on parallaxes from van Altena et al. (1995), van Leeuwen (2007) and Gatewood (2008).

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen F. (2007). "HIP 1475". Validation of the new Hipparcos reduction. Retrieved 2014-10-20.
  2. ↑ 2.0 2.1 2.2 Berger, D. H. et al. (2006). "First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars". The Astrophysical Journal 644 (1): 475–483. arXiv:astro-ph/0602105. Bibcode:2006ApJ...644..475B. doi:10.1086/503318.
  3. ↑ 3.0 3.1 http://arxiv.org/abs/1408.5645
  4. ↑ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 15". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-10-20.
  5. ↑ Gliese, W. and Jahreiß, H. (1991). "Gl 15". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-10-20.
  6. ↑ Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 49". The General Catalogue of Trigonometric Stellar Parallaxes (Fourth ed.). Retrieved 2014-10-20.
  7. ↑ Perryman et al. (1997). "HIP 1475". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
  8. ↑ Perryman et al. (1997). "HIP 1475". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
  9. ↑ Gatewood, George (2008). "Astrometric Studies of Aldebaran, Arcturus, Vega, the Hyades, and Other Regions". The Astronomical Journal 136 (1): 452–460. Bibcode:2008AJ....136..452G. doi:10.1088/0004-6256/136/1/452.
  10. ↑ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-10-20.
  11. ↑ 11.0 11.1 Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Berta-Thompson, Zachory K. (2014). "Trigonometric Parallaxes for 1507 Nearby Mid-to-late M Dwarfs". The Astrophysical Journal 784 (2): 156. arXiv:1312.3241. Bibcode:2014ApJ...784..156D. doi:10.1088/0004-637X/784/2/156.
  12. ↑ Andrew Howard, Geoffrey Marcy, Debra A. Fischer, Howard Isaacson, Philip S. Muirhead, Gregory W. Henry, Tabetha S. Boyajian, Kaspar von Braun, Juliette C. Becker, Jason T. Wright, John Asher Johnson, Astrophysics Earth and Planetary Astrophysics : The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth.

External links

Components

NAME Right ascension Declination Apparent magnitude (V) Spectral type Database references
ADS 246 B (ADS 246 AB) 00h 18m 24s +44° 01' 00 11.0 Simbad
ADS 246 C (V* GQ And) 00h 18m 25.868s +44° 01' 38.44 11.4 M3.5 Simbad
ADS 246 D (GJ 15 C) 00h 18m 00.13s +44° 00' 29.2 11.4 M5 Simbad