Groombridge 34

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Groombridge 34
File:GXAndLightCurve.png
Ultraviolet band light curves for GX Andromedae, with flares marked by red arrows. Adapted from Pettersen and Griffin (1980)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Groombridge 34 A
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 8.119[3]
Groombridge 34 B
Right ascension Template:RA[4]
Declination Template:DEC[4]
Apparent magnitude (V) 11.007[3]
Characteristics
Spectral type M1.4V + M4.1V[3]
U−B Template:Engvar +1.24/+1.40[5]
B−V Template:Engvar +1.56/+1.80[5]
Variable type Flare stars
Astrometry
Groombridge 34 A
Radial velocity (Rv)Template:Val[6] km/s
Proper motion (μ) RA: Template:Val mas/yr[2]
Dec.: Template:Val mas/yr[2]
Parallax (π)280.7068±0.0203 mas[2]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)10.32Script error: No such module "Unsubst".
Groombridge 34 B
Radial velocity (Rv)Template:Val[4] km/s
Proper motion (μ) RA: Template:Val mas/yr[4]
Dec.: Template:Val mas/yr[4]
Parallax (π)280.6947±0.0278 mas[4]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)13.3Script error: No such module "Unsubst".
Orbit[7]
Period (P)Template:Val years
Semi-major axis (a)Template:Val[8] AU
Eccentricity (e)Template:Val
Inclination (i)Template:Val°
Longitude of the node (Ω)Template:Val°
Periastron epoch (T)Template:Val
Argument of periastron (ω)
(secondary)		Template:Val°
Details
Groombridge 34 A
MassTemplate:Val[9] Template:Solar mass
RadiusTemplate:Val[9] Template:Solar radius
Luminosity0.02249±0.00019[9] Template:Solar luminosity
Habitable zone inner limit0.112[10] AU
Habitable zone outer limit0.239[10] AU
Surface gravity (log g)Template:Val[8] cgs
TemperatureTemplate:Val[9] K
Metallicity [Fe/H]Template:Val[8] dex
RotationTemplate:Val[11] days
Rotational velocity (v sin i)Template:Val[8] km/s
Age~3.02[3] Gyr
Groombridge 34 B
MassTemplate:Val[8] Template:Solar mass
RadiusTemplate:Val[8] Template:Solar radius
Luminosity~8.5Template:E[8] Template:Solar luminosity
Habitable zone inner limit0.048[10] AU
Habitable zone outer limit0.103[10] AU
Surface gravity (log g)Template:Val[8] cgs
TemperatureTemplate:Val[8] K
Metallicity [Fe/H]Template:Val[3] dex
RotationTemplate:Val[11] days
Age~2.754[3] Gyr
Other designations
GX/GQ Andromedae, BD+43° 44, GCTP 49, GJ 15 A/B, G 171-047/171-048, HD 1326, HIP 1475, LHS 3/4, LTT 10108/10109, SAO 36248, PPM 42798[12]
Database references
SIMBADGJ 15 A
GJ 15 Ab
GJ 15 B
Exoplanet Archivedata
ARICNSGJ 15 A
GJ 15 B
Script error: No such module "Location map".

Script error: No such module "Check for unknown parameters".

Groombridge 34 is a binary star system in the northern constellation of Andromeda. It was listed as entry number 34 in A Catalogue of Circumpolar Stars, published posthumously in 1838 by British astronomer Stephen Groombridge.[13] Based upon parallax measurements taken by the Gaia spacecraft, the system is located about Template:Convert from the Sun. This positions the pair among the nearest stars to the Solar System.

Both components are small, dim red dwarf stars that are too faint to be seen with the naked eye. They orbit around their common barycenter in a fairly eccentric orbit with a separation of about 93 AU and a period of around 1,065 years.[8][7] Both stars exhibit random variation in luminosity due to flares and they have been given variable star designations: the brighter member Groombridge 34 A is designated GX And, while the smaller component is designated GQ And.[14]

The star system has a relatively high proper motion of 2.9 arc seconds per year,[15] and is moving away from the Solar System at a velocity of 11.6 km/s.[6] It achieved perihelion some 15,000 years ago when it came within Template:Cvt of the Sun.[15]

GX Andromedae

The more massive and luminous component of the pair has the variable star designation GX Andromedae. It is a main-sequence red dwarf star of spectral type M1.4[3] that varies its brightness due to stellar flares. Gaia observations suggest a rotation period of 44 days and a magnetic activity cycle of roughly 9 years.[16]

GQ Andromedae

The smaller companion bears the variable star name GQ Andromedae. It is a red dwarf main sequence star that undergoes flare events like the primary; it has a spectral type M4.1,[3] so it also has a lower effective temperature.

Planetary system

In August 2014, a planet orbiting around Groombridge 34 A was reported.[17] 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. At the time of its discovery, it was the sixth-nearest-known exoplanet.

Using the CARMENES spectrograph combined with the measurements of the HARPS and HIRES spectrographs, researchers failed to detect the purported Groombridge 34 Ab. However, they did propose that another planet (Groombridge 34 Ac, GJ 15 Ac) could be orbiting the parent star.[18]

This discrepancy was later reconciled with new HIRES observations, covering a longer span of time, where both planets were recovered, constraining their minimum mass to 3.03 Template:Earth mass for Groombridge 34 Ab and 36 Template:Earth mass for Groombridge Ac. Their orbital periods are 11.4 and approximately 7,600 days, respectively. To date, this is the fourth-closest confirmed multi-planet system to the Sun, hosting the longest-period Neptune-mass exoplanet discovered so far.[8]

Template:OrbitboxPlanet begin Template:OrbitboxPlanet Template:OrbitboxPlanet Template:Orbitbox end

See also

References

Template:Reflist

External links

Template:Nearest systems Template:Stars of Andromeda

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Pettersen
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named Gaia DR3 A
  3. ↑ a b c d e f g h Cite error: Invalid <ref> tag; no text was provided for refs named apj804_1_64
  4. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named Gaia DR3 B
  5. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named MERMILLIOD
  6. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Nidever2002
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Izmailov2025
  8. ↑ a b c d e f g h i j k Cite error: Invalid <ref> tag; no text was provided for refs named Pinamonti2018
  9. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named Pineda2021
  10. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named aaa555_A104
  11. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Kemmer2025
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named groombridge1838
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named petit1990
  15. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aa575_A35
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Morris2018
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named apj794_1_51
  18. ↑ Script error: No such module "Citation/CS1".
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