Gliese 777

Short description: Binary star in the constellation Cygnus

Gliese 777

Location of Gliese 777 (circled in red)

Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| Epoch J2000.0 [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation | Cygnus[1]

Right ascension |  20h 03m 37.405s[2]
Declination | +29° 53′ 48.49″[2]
Apparent magnitude (V) | +5.73[3]

Right ascension |  20h 03m 26.581s[4]
Declination | +29° 51′ 59.53″[4]
Apparent magnitude (V) | +14.4[5]
Characteristics

Evolutionary stage | main sequence[2][6]
Spectral type | G6IV[3]

Evolutionary stage | main sequence[7]
Spectral type | M4.5V[8]
Astrometry

Radial velocity (Rv)| −45.34±0.12[2] km/s
Proper motion (μ)|  RA: +683.196[2] mas/yr
Dec.: −525.501[2] mas/yr
Parallax (π)| 62.4865 ± 0.34[2] mas
Distance| 52.2 ± 0.3 ly
(16.00 ± 0.09 pc)
Absolute magnitude (MV)| +4.73[1]

Radial velocity (Rv)| −44.02±0.40[4] km/s
Proper motion (μ)|  RA: +681.116 mas/yr
Dec.: −525.863 mas/yr
Parallax (π)| 62.5269 ± 0.0225[4] mas
Distance| 52.16 ± 0.02 ly
(15.993 ± 0.006 pc)
Absolute magnitude (MV)| +13.3[5]
Details

Mass| 0.991+0.039
−0.040[9] M☉
Radius| 1.142±0.009[10] R☉
Luminosity| 1.114±0.007[10] L☉
Surface gravity (log g)| 4.292±0.012[10] cgs
Temperature| 5,557±22[10] K
Metallicity [Fe/H]| 0.17±0.04[10] dex
Rotation| 40[11] days
Rotational velocity (v sin i)| 2.8[11] km/s
Age| 4.79[3] Gyr

Mass| 0.21[12] M☉
Radius| 0.24[12] R☉
Luminosity| 0.0044[13] L☉
Surface gravity (log g)| 4.84[14] cgs
Temperature| 3.169[12] K
Rotational velocity (v sin i)| 7.1[14] km/s
Age| 2.5[7] Gyr
Other designations

GJ 777

A: BD+29°3872, HD 190360, HIP 98767, HR 7670, LHS 3510
B: G 125-55, LHS 3509
Database references
SIMBAD| A
| B
Exoplanet Archive| data
ARICNS| data
| data2
Extrasolar Planets
Encyclopaedia| data

Gliese 777, also known as HD 190360, is a binary star system approximately 52 light-years away in the constellation of Cygnus. The system is made up of two stars and possibly a third. Three exoplanets are known to orbit the primary star.

## Contents

* 1 Stellar components
* 2 Planetary system
* 3 See also
* 4 References
* 5 External links

## Stellar components

The primary star of the system (catalogued as Gliese 777 A) is a yellow subgiant, a Sun-like star that is ceasing fusing hydrogen in its core. The star is much older than the Sun, about 6.7 billion years old. It is 4% less massive than the Sun. It is also rather metal-rich, having about 70% more "metals" (elements heavier than helium) than the Sun, which is typical for stars with extrasolar planets.

The secondary star (Gliese 777 B) is a distant, dim red dwarf star orbiting the primary at a distance of 3,000 astronomical units (0.047 light years). A faint companion has been reported, but not confirmed.[15]

## Planetary system

In 2002, a discovery of a long-period, wide-orbiting, planet (Gliese 777 Ab) was announced by the Geneva extrasolar planet search team.[16] The planet was estimated to orbit in a circular path with low orbital eccentricity, but that estimate was increased with later measurements (e=0.36).[17] Initially therefore, the planet was believed to be a true "Jupiter-twin" but was later redefined as being more like an "eccentric Jupiter", with a mass of at least 1.5 times Jupiter and about the same size. In 2021, the true mass of Gliese 777 Ab was measured via astrometry.[18]

In 2005, further observation of the star showed another amplitude with a period of 17.1 days.[17] The mass of this second planet (Gliese 777 Ac) was only 18 times more than Earth, or about the same as Neptune, indicating it was one of the smallest planets discovered at the time. Initially thought to be on a circular orbital path (e = 0.01),[17] Gliese 777 c was revealed to have a more eccentric orbit with later measurements.[9]

Evidence for a third candidate planet with an orbital period around 89 days was presented in 2025.[9] It was confirmed in the same year.[19]

The HD 190360 (Gliese 777 A) planetary system[19] Companion
(in order from star) | Mass | Semimajor axis
(AU) | Orbital period
(years) | Eccentricity | Inclination | Radius

|
|
|
|
|
|

c | 26.1+25.7
−4.1 M⊕ | 0.1296+0.0017
−0.0018 | 0.0468627(11)
(17.12 d)  | 0.163+0.020
−0.019 | 95+46
−51° | —
d | ≥10.23+0.81
−0.80 M⊕ | 0.3886±0.0046 | 0.2430±0.0001 | 0.058+0.062
−0.040 | —  | —
b | 1.68+0.26
−0.16[9] MJ | 3.965±0.047 | 7.906±0.010 | 0.3342+0.0061
−0.0062 | 69+42
−17[9]° | —

There was a METI message sent to Gliese 777. It was transmitted from Eurasia's largest radar, 70-meter Eupatoria Planetary Radar. The message was named Cosmic Call 1; it was sent on July 1, 1999, and it will arrive at Gliese 777 in April 2051.[20]

## See also

* 47 Ursae Majoris
* 51 Pegasi
* Gliese 229

## References

1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
3. ↑ 3.0 3.1 3.2 Ligi, R. et al. (February 2016), "Radii, masses, and ages of 18 bright stars using interferometry and new estimations of exoplanetary parameters", Astronomy & Astrophysics 586: 23, doi:10.1051/0004-6361/201527054, A94, Bibcode: 2016A&A...586A..94L.
4. ↑ 4.0 4.1 4.2 4.3 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.
5. ↑ 5.0 5.1 Houdebine, Éric R.; Mullan, D. J.; Doyle, J. G.; de la Vieuville, Geoffroy; Butler, C. J.; Paletou, F. (2019). "The Mass-Activity Relationships in M and K Dwarfs. I. Stellar Parameters of Our Sample of M and K Dwarfs". The Astronomical Journal 158 (2): 56. doi:10.3847/1538-3881/ab23fe. Bibcode: 2019AJ....158...56H.
6. ↑ Just, A.; Jahrei, H. (2008). "The main sequence from F to K stars of the solar neighbourhood in SDSS colours". Astronomische Nachrichten 329 (8): 790. doi:10.1002/asna.200811030. Bibcode: 2008AN....329..790J.
7. ↑ 7.0 7.1 Mann, Andrew W.; Feiden, Gregory A.; Gaidos, Eric; Boyajian, Tabetha; von Braun, Kaspar (2015). "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius". The Astrophysical Journal 804 (1): 64. doi:10.1088/0004-637X/804/1/64. Bibcode: 2015ApJ...804...64M.
8. ↑ Alonso-Floriano, F. J.; Morales, J. C.; Caballero, J. A.; Montes, D.; Klutsch, A.; Mundt, R.; Cortés-Contreras, M.; Ribas, I. et al. (2015). "CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS". Astronomy and Astrophysics 577: A128. doi:10.1051/0004-6361/201525803. Bibcode: 2015A&A...577A.128A.
9. ↑ 9.0 9.1 9.2 9.3 9.4 Giovinazzi, Mark R.; Blake, Cullen H.; Robertson, Paul; Lin, Andrea S. J.; Gupta, Arvind F.; Mahadevan, Suvrath; Fernandes, Rachel B.; Wright, Jason T. et al. (2025). "The NEID Earth Twin Survey. II. Dynamical Masses in Seven High-acceleration Star Systems". The Astronomical Journal 170 (1): 52. doi:10.3847/1538-3881/add922. Bibcode: 2025AJ....170...52G.
10. ↑ 10.0 10.1 10.2 10.3 10.4 Karovicova, I.; White, T. R.; Nordlander, T.; Casagrande, L.; Ireland, M.; Huber, D. (13 September 2021). "Fundamental stellar parameters of benchmark stars from CHARA interferometry -- II. Dwarf stars". Astronomy & Astrophysics 658: A47. doi:10.1051/0004-6361/202141833. ISSN 0004-6361. Bibcode: 2022A&A...658A..47K.
11. ↑ 11.0 11.1 Tejada Arevalo, Roberto A.; Winn, Joshua N.; Anderson, Kassandra R. (2021). "Further Evidence for Tidal Spin-up of Hot Jupiter Host Stars". The Astrophysical Journal 919 (2): 138. doi:10.3847/1538-4357/ac1429. Bibcode: 2021ApJ...919..138T.
12. ↑ 12.0 12.1 12.2 Sebastian, D.; Gillon, M.; Ducrot, E.; Pozuelos, F. J.; Garcia, L. J.; Günther, M. N.; Delrez, L.; Queloz, D. et al. (2021). "SPECULOOS: Ultracool dwarf transit survey. Target list and strategy". Astronomy and Astrophysics 645. doi:10.1051/0004-6361/202038827. Bibcode: 2021A&A...645A.100S.
13. ↑ Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal 165 (6): 267. doi:10.3847/1538-3881/acd1ec. Bibcode: 2023AJ....165..267H.
14. ↑ 14.0 14.1 Jönsson, Henrik; Holtzman, Jon A.; Allende Prieto, Carlos; Cunha, Katia; García-Hernández, D. A.; Hasselquist, Sten; Masseron, Thomas; Osorio, Yeisson et al. (2020). "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South". The Astronomical Journal 160 (3): 120. doi:10.3847/1538-3881/aba592. Bibcode: 2020AJ....160..120J.
15. ↑ Heintz, W. D. (1988). "Photographic Astrometry of Binary and Proper-Motion Stars. IV.". The Astronomical Journal 96: 1072. doi:10.1086/114867. Bibcode: 1988AJ.....96.1072H.
16. ↑ Naef, D. et al. (2003). "The ELODIE survey for northern extra-solar planets II. A Jovian planet on a long-period orbit around GJ 777 A". Astronomy and Astrophysics 410 (3): 1051–1054. doi:10.1051/0004-6361:20031341. Bibcode: 2003A&A...410.1051N.
17. ↑ 17.0 17.1 17.2 Vogt, Steven S. et al. (2005). "Five New Multicomponent Planetary Systems". The Astrophysical Journal 632 (1): 638–658. doi:10.1086/432901. Bibcode: 2005ApJ...632..638V. https://authors.library.caltech.edu/36250/1/0004-637X_632_1_638.pdf. Retrieved 2020-09-05.
18. ↑ Feng, Fabo; Butler, R Paul; Jones, Hugh R A.; Phillips, Mark W.; Vogt, Steven S.; Oppenheimer, Rebecca; Holden, Bradford; Burt, Jennifer et al. (2021). "Optimized modelling of Gaia–Hipparcos astrometry for the detection of the smallest cold Jupiter and confirmation of seven low-mass companions". Monthly Notices of the Royal Astronomical Society 507 (2): 2856–2868. doi:10.1093/mnras/stab2225. Bibcode: 2021MNRAS.507.2856F.
19. ↑ 19.0 19.1 Giovinazzi, Mark R.; Fitzmaurice, Evan; Gupta, Arvind F.; Robertson, Paul; Mahadevan, Suvrath; Ford, Eric B.; Alvarado-Montes, Jaime A.; Bender, Chad F.; Blake, Cullen H.; Dong, Jiayin; Fernandes, Rachel B.; Halverson, Samuel; Han, Te; Kanodia, Shubham; Krolikowski, Daniel M.; Logsdon, Sarah E.; Ninan, Joe P.; Roy, Arpita; Schwab, Christian; Stefansson, Gudmundur; Terrien, Ryan C.; Wright, Jason T. (2025). "The NEID Earth Twin Survey. IV. Confirming an 89 d, m sin i = 10 M⊕ Planet Orbiting a Nearby Sun-like Star". arXiv:2508.18169 [astro-ph.EP].
20. ↑ Script error: The function "in_lang" does not exist. http://www.cplire.ru/rus/ra&sr/VAK-2004.html

## External links

* Extrasolar Planet Interactions by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona

Template:Gliese 777

* v
* t
* e

Constellation of Cygnus

* List of stars in Cygnus

Stars|

| Bayer|

* α (Deneb)
* β (Albireo)
* γ (Sadr)
* δ (Fawaris)
* ε (Aljanah)
* ζ
* η
* θ
* ι1
* ι2
* κ
* λ
* μ
* ν
* ξ
* π1 (Azelfafage)
* π2
* ρ
* σ
* τ
* υ
* φ
* χ
* ψ
* ω1
* ω2
* P
* Q

|

Flamsteed|

* 2
* 4
* 8
* 9
* 14
* 15
* 16 (c)
* 17
* 20 (d)
* 22
* 23
* 26 (e)
* 27 (b1)
* 28 (b2)
* 29 (b3)
* 30
* 31
* 32
* 33
* 35
* 39
* 41
* 47
* 52
* 55
* 56
* 57
* 59 (f1)
* 61
* 63 (f2)
* 68 (A)
* 71 (g)
* 72
* 74
* 75

Variable|

* R
* T
* W
* RW
* SS
* TT
* BC
* BI
* CH
* KY
* V404
* V476
* V1057
* V1143
* V1191
* V1489
* V1500
* V1668
* V1974
* V2513

HR|

* 7633
* 7912
* 8193

HD|

* 185269
* 185435
* 187123
* 188753
* 191806

Gliese|

* 777
* 806
* 1245

Kepler|

* 5
* 6
* 11
* 15
* 16
* 17
* 18
* 22
* 23
* 27
* 28
* 29
* 31
* 32
* 33
* 34
* 35
* 36
* 39
* 40
* 41
* 42
* 43
* 44
* 45
* 47
* 51
* 56
* 61
* 66
* 67
* 68
* 69
* 70
* 78
* 80
* 84
* 86
* 89
* 107
* 182
* 186
* 223
* 371
* 419
* 432
* 451
* 452
* 1229
* 1520
* 1625

Other|

* AFGL 2591
* BD+40° 4210
* BD+43 3654
* Cygnus OB2 #8A
* Cygnus OB2 #12
* Cygnus X-1
* Cygnus X-3
* G 208-44
* G 208-45
* HAT-P-7
* HAT-P-11
* HAT-P-17
* KELT-9
* KIC 8462852
* KIC 9832227
* KIC 11026764
* KOI-74
* KOI-81
* KOI-256
* KPD 1930+2752
* MWC 349
* N6946-BH1
* NML Cygni
* PH1
* PSR J2032+4127
* W75N(B)-VLA2
* WISE J2000+3629
* WR 134
* WR 135
* WR 136
* WR 137
* WR 140
* WR 142
* WR 147
* WR 148

Former|

* 3

Star
clusters|

| Association|

* Cygnus OB2
* Cygnus OB7

|

Open|

* DR 6
* IC 5146
* Messier 29
* Messier 39
* NGC 6811
* NGC 6819
* NGC 6834
* NGC 6866
* NGC 6871
* NGC 6910

Molecular
clouds|

* Cygnus X (including DR 21)

Nebulae|

| Dark|

* Barnard 146
* Barnard 147
* IC 5146
* L1014

|

H II|

* NGC 6914
* North America Nebula
* Pelican Nebula
* Sadr Region
* Sh2-101
* Sh2-106

Planetary|

* Abell 78
* Egg Nebula
* IRAS 19475+3119
* Kronberger 61
* M1-92
* NGC 6826
* NGC 6881
* NGC 6884
* NGC 7008
* NGC 7026
* NGC 7027
* NGC 7048
* Soap Bubble Nebula

WR|

* Crescent Nebula

SNR|

* Cygnus Loop (including Veil Nebula)

Galaxies|

| NGC|

* 6801
* 6946
* 7013

|

Other|

* 3C 438
* Cygnus A

Coordinates:  20h 03m 37.41s, +29° 53′ 48.50″

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