GJ 1061

GJ 1061

GJ 1061 Location of GJ 1061 in the constellation Horologium
Observation data Epoch J2000       Equinox J2000
Constellation	Horologium
Right ascension	03h 35m 59.69916s [1]
Declination	−44° 30′ 45.7308″ [1]
Apparent magnitude  (V)	13.03 [2]
Characteristics
Spectral type	M5.5 V [2]
Apparent magnitude  (J)	7.52 ± 0.02 [3]
U−B color index	1.52 [3]
B−V color index	1.90 [3]
Astrometry
Radial velocity (Rv)	1.49±0.23 [1] km/s
Proper motion (μ)	RA: 745.654 mas/yr [1] Dec.: −373.323 mas/yr [1]
Parallax (π)	272.1615±0.0316  mas [1]
Distance	11.984 ± 0.001  ly (3.6743 ± 0.0004  pc)
Absolute magnitude  (MV)	15.26 [4]
Details
Mass	0.125±0.003 [5]   M☉
Radius	0.152±0.007 [5]   R☉
Luminosity (bolometric)	0.001641±0.000037 [5]   L☉
Luminosity (visual, LV)	0.00007 [nb 1]   L☉
Temperature	2,977+72 −69 [5]   K
Metallicity [Fe/H]	−0.03±0.09 [5]   dex
Rotational velocity (v sin i)	≤ 5 [6]  km/s
Age	>7.0±0.5 [7]   Gyr
Other designations
GJ 1061, LHS 1565, LFT 295, LTT 1702, LP 995-46, L 372-58 [3]
Database references
SIMBAD	data
Exoplanet Archive	data

GJ 1061 is a red dwarf star located 12 light-years (3.7 parsecs ) from Earth in the southern constellation of Horologium. Even though it is a relatively nearby star, it has an apparent visual magnitude of about 13, ^[2] so it can only be seen with at least a moderately-sized telescope.

The proper motion of GJ 1061 has been known since 1974, but it was estimated to be further away: approximately 25 light-years (7.7 parsecs) distant based upon an estimated parallax of 0.130″. The RECONS accurately determined its distance in 1997. At that time, it was the 20th-nearest star system to the Sun. The discovery team noted that many more stars like this are likely to be discovered nearby. ^[2]

This star is a tiny, dim, red dwarf, close to the lower mass limit. It has an estimated mass of about 12.5% that of the Sun and is only about 0.2% as luminous. ^[5] The star displays no significant infrared excess due to circumstellar dust. ^[8]

Planetary system

On August 13, 2019, a planetary system was announced orbiting the star GJ 1061 by the Red Dots project for detecting terrestrial planets around nearby red dwarf stars. ^[7] The planet GJ 1061 d orbits in the conservative circumstellar habitable zone of its star and the planet GJ 1061 c orbits in the inner edge of the habitable zone. ^[7] GJ 1061 is a non-variable star that does not suffer flares, so there is a greater probability that the exoplanets still conserve their atmosphere if they had one. ^[9]

The GJ 1061 planetary system ^[7]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥1.37+0.16 −0.15  M🜨	0.021±0.001	3.204±0.001	<0.31	—	—
c	≥1.74±0.23  M🜨	0.035±0.001	6.689±0.005	<0.29	—	—
d	≥1.64+0.24 −0.23  M🜨	0.054±0.001	13.031+0.025 −0.032	<0.53	—	—

GJ 1061 c

GJ 1061 c is a potentially habitable exoplanet orbiting within the limits of the optimistically defined habitable zone of its red dwarf parent star. ^{[10] [11] [7]}

GJ 1061 c is at least 74% more massive than the Earth. The planet receives 35% more stellar flux than Earth and has an equilibrium temperature of 275 K (2 °C; 35 °F). ^[12] The average temperature on the surface would be warmer, 34 °C (307 K; 93 °F), provided the atmosphere is of similar composition to the Earth's.

GJ 1061 c orbits its parent star very closely, every 6.7 days at a distance of just 0.035 au, so it is probably gravitationally locked and in synchronous rotation with its star.

GJ 1061 d

GJ 1061 d is a potentially habitable exoplanet largely orbiting within the limits of the conservatively defined habitable zone of its parent red dwarf star. ^{[10] [13] [7]}

The exoplanet is at least 64% more massive than the Earth. The planet receives about 40% less stellar flux than Earth and has an estimated equilibrium temperature of 218 K (−55 °C; −67 °F). ^{[10] [7]} The average temperature on the surface would be colder than Earth's and at around 250 K (−23 °C; −10 °F), provided the atmosphere is similar to that of Earth.

GJ 1061 d orbits its star every 13 days, and due to its close-in semi-major axis, it is likely that the exoplanet is tidally locked. ^[14] However, if the planet's orbit is confirmed to be highly eccentric then this eccentricity could be desynchronising it, enabling the existence of non-synchronised states of equilibrium in its rotation, relative to which side of the planet is facing the star, and thereby it will experience a day/night cycle. ^[15]

Another solution for this planet gives it a slightly shorter period of 12.4 days and a slightly smaller minimum mass of 1.53 M_E. ^[7]

See also

• List of nearest stars and brown dwarfs
• Research Consortium On Nearby Stars
• List of exoplanets discovered in 2020 - GJ 1061 b, c, & d

Notes

1. Taking the absolute visual magnitude of GJ 1061, ${\displaystyle \scriptstyle M_{V_{\ast }}=15.26}$, and the absolute visual magnitude of the Sun, ${\displaystyle \scriptstyle M_{V_{\odot }}=4.83}$, the visual luminosity of GJ 1061 can therefore be calculated: ${\displaystyle \scriptstyle {\frac {L_{V_{\ast }}}{L_{V_{\odot }}}}=10^{0.4\left(M_{V_{\odot }}-M_{V_{\ast }}\right)}=6.73\times 10^{-5}}$

References

9. Starr, Michelle (27 August 2019). "Three Rocky Exoplanets Have Been Found Orbiting a Star Just 12 Light-Years Away". ScienceAlert. Retrieved 2020-10-07.
10. "The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo". phl.upr.edu. Retrieved 2020-03-31.
11. "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 2020-03-31.
12. "Trio of Super-Earths Found Orbiting Red Dwarf Gliese 1061 | Astronomy | Sci-News.com". Breaking Science News | Sci-News.com. Retrieved 2020-03-31.
13. "GJ 1061 d". exoplanetarchive.ipac.caltech.edu. Retrieved 2020-10-07.
14. "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 2020-10-07.
15. Auclair-Desrotour, P.; et al. (2019). "Final spin states of eccentric ocean planets". Astronomy & Astrophysics. 629. EDP Sciences: A132. arXiv: 1907.06451 . Bibcode:2019A&A...629A.132A. doi: 10.1051/0004-6361/201935905 . ISSN   0004-6361. While the semidiurnal tide drives the body towards the spin-orbit synchronous rotation, eccentricity tides tend to desynchronise it, and thereby enable the existence of non-synchronised states of equilibrium.

External links

• SolStation.com: GJ 1061