Peter 876

Database links to Gliese 876

Star gliese 876
Artist's impression of Gliese 876 and the planet Gliese 876 b with hypothetical exomondes
AladinLite
Observation dates equinox :  J2000.0 , epoch : J2000.0
Constellation	Aquarius
Right ascension	22 h 53 m 16.73 s
declination	-14 ° 15 ′ 49.3 ″
Apparent brightness	10.15 (10.15-10.21) mag
Typing
Known exoplanets	4th
B − V color index	+1.56
U − B color index	+1.18
R − I index	+1.55
Spectral class	M3.5 V
Variable star type	BY
Astrometry
Radial velocity	−1.52 ± 0.16 km / s
parallax	213.89 ± 0.08  mas
distance	15.24 ± 0.01  Lj 4.675 ± 0.002  pc
Visual absolute brightness M vis	+11.79 mag
Proper movement
Rec. Share:	+957.96 ± 0.12  mas / a
Dec. portion:	−673.64 ± 0.10  mas / a
Physical Properties
Dimensions	(0.346 ± 0.007)  M ☉
radius	(0.352 ± 0.011)  R ☉
Luminosity	0.013  L ☉
Effective temperature	3473 ±  17K
Metallicity [Fe / H]	+0.19 ± 0.17
Rotation time	96.9 d
Age	0.1-9.9 billion  a
Other names and catalog entries
Bonn survey BD −15 ° 6290 Gliese catalog FY 876 [1] Hipparcos catalog HIP 113020 [2] Tycho catalog TYC 5819-1255-1 [3] 2MASS catalog 2MASS J22531672-1415489 [4] Other names IL Aquarii, Ross 780, G 156-057, GCTP 5546.00, Vys 337

Gliese 876 is a red dwarf in the constellation Aquarius , of about 15 light-years from the sun is removed. It is one of the closest neighbors to the sun, where the existence of a planetary system has been confirmed. The Gliese 876 planetary system consists of four known exoplanets .

Despite its (comparatively) proximity to Earth , the star, like all red dwarfs, is far too faint to be observed with the naked eye.

properties

Gliese 876 is significantly smaller, less massive and less light than the sun. Its mass is only about a third of the solar mass and its luminosity is only 1.3% of the solar luminosity . The star's metallicity is also less than that of the sun. Measurements of the activity of the Gliese 876 chromosphere indicate an age of 6.5 to 9.9 billion years. In contrast, the space movement of the star within the Milky Way suggests that it belongs to the disk population and is therefore between 0.1 and 5 billion years old.

Gliese 876 is a BY Draconis variable and as such carries the variable designation IL Aquarii . Its brightness varies between 10.150 mag at the maximum and 10.210 mag at the minimum. The star also emits X-rays .

Planetary system

Orbits in the planetary system of Gliese 876

Using the radial velocity method , a planet around Gliese 876 was independently detected in 1998 by two teams of astronomers, led by Geoffrey W. Marcy and Xavier Delfosse . It was the first discovery of an exoplanet in orbit around a red dwarf. The planet with the designation Gliese 876 b was also the closest exoplanet to the sun at this point in time. It has a minimum mass of a little more than the mass of Jupiter .

A second planet, named Gliese 876 c , was also discovered in 2001 by Marcy et al. discovered. Its orbit runs closer to the star than that of the first discovered planet and lies in the habitable zone of Gliese 876. The minimum mass is a little more than 0.7 Jupiter masses.

Further measurements of the radial velocity of Gliese 876 carried out with high precision led to the detection of a third planet, Gliese 876 d , by a team of astronomers led by Eugenio Rivera in 2005 . It is the innermost planet in the system and the first super-earth- classified exoplanet around a main sequence star .

The minimum mass of Gliese 876 d was initially estimated to be about 7.53 earth masses, later to about 6.83 earth masses. According to an investigation from 2014, it is around 5.85 Earth masses.

Another group of astronomers led by Eugenio Rivera discovered in 2010 a fourth planet orbiting Gliese 876 , Gliese 876 e . The minimum mass of Gliese 876 e roughly corresponds to the mass of the planet Uranus in the solar system .

The orbits of the three outer planets Gliese 876 b, Gliese 876 c and Gliese 876 e are in a Laplace resonance , comparable to the three large Jupiter moons Io , Europa and Ganymede . It is believed that the three outer planets were formed at a greater distance from the star and then migrated into their current orbits.

Studies of the radial velocity of Gliese 876, published in 2014, suggest that there are two other planets in the system. These would orbit their central star in about 10.01 and 15.04 days, respectively. A confirmation of this is still pending.

Planetary system of Gliese 876

Planet (by distance from the star)	Discovery (year)	Mass (in M ♁ )	Cycle time (in days)	Major semi-axis (in AU )	Orbit inclination (in ) ${\displaystyle \mathrm {^{\circ }} }$	eccentricity
Gliese 876 d	2005	6.91   +0.22−0.27	1.938 ± 0.001	0.021 ± 0.001	59	0.082   +0.043−0.025
Gliese 876 c	2001	241.5   +0.7−0.6	30.126   +0.011−0.003	0.134 ± 0.001	59	0.250   + 0.001−0.002
Gliese 876 b	1998	760.9 ± 1.0	61.082   + 0.006−0.010	0.214 ± 0.001	59	0.040   +0.021−0.004
Gliese 876 e	2010	15.43   +1.29−1.27	124.4   +0.3−0.7	0.345   + 0.001−0.002	59	0.040   +0.021−0.004

Web links

Commons : Gliese 876  - Collection of images, videos and audio files

• SolStation.com: Gliese 876 / Ross 780. Retrieved June 28, 2015 . 

Individual evidence

1. ↑ ^{a b c d e f g} BD-15 6290. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on November 10, 2018 . 
2. ↑ VizieR: GJ 876. Retrieved June 28, 2015 . 
3. ↑ ^{a b} IL Aqr. In: VSX. AAVSO, accessed November 10, 2018 . 
4. ↑ ^{a b c} P. E. Kervella, F. Arenou, F. Mignard, F. Thévenin: Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly . In: Astronomy & Astrophysics . 623, p. A72. arxiv : 1811.08902 . bibcode : 2019A & A ... 623A..72K . doi : 10.1051 / 0004-6361 / 201834371 .
5. ^ ^{A b c d} Correia, ACM et al .: The HARPS search for southern extra-solar planets XIX. Characterization and dynamics of the GJ876 planetary system . arxiv : 1001.4774 .
6. ↑ ^{a b} Rojas-Ayala, Bárbara et al .: Metallicity and Temperature Indicators in M ​​dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs . arxiv : 1112.4567 .
7. ↑ ^{a b} Saffe, C .; Gomez, M .; Chavero, C .: On the Ages of Exoplanet Host Stars . arxiv : astro-ph / 0510092 .
8. ^ VizieR: IL Aqr. Retrieved June 28, 2015 . 
9. ↑ Schmitt, Jürgen HMM; Fleming, Thomas A .; Giampapa, Mark S .: The X-ray view of the low-mass stars in the solar neighborhood . bibcode : 1995ApJ ... 450..392S .
10. ^ Marcy, Geoffrey W. et al .: A Planetary Companion to the Nearby M4 Dwarf, Gliese 876 . arxiv : astro-ph / 9807307 .
11. ↑ Delfosse, X. et al .: The closest extrasolar planet: A giant planet around the M4 dwarf Gl 876 . arxiv : astro-ph / 9808026 .
12. ^ Marcy, Geoffrey W. et al .: A Pair of Resonant Planets Orbiting GJ 876 . bibcode : 2001ApJ ... 556..296M .
13. ↑ ^{a b c} Rivera, Eugenio J. et al .: A ~ 7.5 Earth-Mass Planet Orbiting the Nearby Star, GJ 876 . arxiv : astro-ph / 0510508 .
14. ↑ ^{a b} Rivera, Eugenio J. et al .: The Lick-Carnegie Exoplanet Survey: A Uranus-mass Fourth Planet for GJ 876 in an Extrasolar Laplace Configuration . arxiv : 1006.4244 .
15. ^ Kammer, J. et al .: A Spitzer Search for Transits of Radial Velocity Detected Super-Earths . arxiv : 1310.7952 .
16. ↑ Gerlach, E .; Haghighipour, N .: Can GJ 876 host four planets in resonance? arxiv : 1202.5865 .
17. ↑ Jenkins, JS; Yoma, NB; Rojo, P .; Mahu, R .; Wuth, J .: Improved signal detection algorithms for unevenly sampled data. Six signals in the radial velocity data for GJ876 . arxiv : 1403.7646 .
18. ↑ ^{a b c d} The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems. (PDF) October 4, 2017, p. 17 , accessed on January 18, 2018 . doi : 10.1051 / 0004-6361 / 201731442 , arxiv : 1710.01595