Gliese 229

Gliese 229
	; Gliese 229 A and B.
Observation data; Epoch J2000 Equinox J2000
Constellation	Lepus
Right ascension	06h 10m 34.6154s[1]
Declination	−21° 51′ 52.715″[1]
Apparent magnitude (V)	8.14
Characteristics
Evolutionary stage	Main sequence / Brown dwarf
Spectral type	M1Ve / T7V[2]
U−B color index	+1.222[2]
B−V color index	+1.478[2]
Variable type	Flare star
Astrometry
Radial velocity (Rv)	+3.9[3] km/s
Proper motion (μ)	RA: –137.01[1] mas/yr ; Dec.: –714.05[1] mas/yr
Parallax (π)	173.5740 ± 0.0170 mas[4]
Distance	18.791 ± 0.002 ly ; (5.7612 ± 0.0006 pc)
Absolute magnitude (MV)	9.326[5]
Absolute bolometric; magnitude (Mbol)	7.96[6]
Orbit[5]
Companion	Gliese 229 B
Period (P)	237.9+5.1; −4.6 yr
Semi-major axis (a)	33.3+0.4; −0.3 AU
Eccentricity (e)	0.851+0.002; −0.008
Inclination (i)	7.7+7.6; −4.4°
Longitude of the node (Ω)	−29+13; −140°
Periastron epoch (T)	2466912+97; −63
Argument of periastron (ω); (secondary)	−9+140; −13°
Details
A
Mass	0.579[5] M☉
Radius	0.69[7] R☉
Luminosity (bolometric)	0.0430[5] L☉
Luminosity (visual, LV)	0.0158[nb 1] L☉
Temperature	3,700[6] K
Rotational velocity (v sin i)	1[8] km/s
B
Mass	41.6±3.3[9] MJup
Radius	~1.1[10] RJup
Luminosity (bolometric)	~0.000011 L☉
Temperature	869+5; −7[9] K
Other designations
	BD-21°1377, HD 42581, HIP 29295, LHS 1827, NSV 2863, SAO 171334, TYC 5945- 765-1
Database references
SIMBAD	A
	B
	Gliese 229 Location of Gliese 229 in the constellation Lepus;

Gliese 229 (also written as Gl 229 or GJ 229) is a binary system composed of a red dwarf and the first brown dwarf seen by astronomers, about 19 light years away in the constellation Lepus. The primary component has 58% of the mass of the Sun,[5] 69% of the Sun's radius,[7] and a very low projected rotation velocity of 1 km/s at the stellar equator.[8]

The star is known to be a low activity flare star, which means it undergoes random increases in luminosity because of magnetic activity at the surface. The spectrum shows emission lines of calcium in the H and K bands. The emission of X-rays has been detected from the corona of this star.[11] These may be caused by magnetic loops interacting with the gas of the star's outer atmosphere. No large-scale star spot activity has been detected.[2]

The space velocity components of this star are U = +12, V = –11 and W = –12 km/s.[12] The orbit of this star through the Milky Way galaxy has an eccentricity of 0.07 and an orbital inclination of 0.005.[2]

Planetary system

A substellar companion was discovered in 1994 by Caltech astronomers Kulkarni, Tadashi Nakajima, Keith Matthews, and Rebecca Oppenheimer, and Johns Hopkins scientists Sam Durrance and David Golimowski. It was confirmed in 1995 as Gliese 229B,[13][14] one of the first two instances of clear evidence for a brown dwarf, along with Teide 1. Although too small to sustain hydrogen-burning nuclear fusion as in a main sequence star, with a mass of 70 times that of Jupiter (0.07 solar masses),[15] it is still too massive to be a planet. As a brown dwarf, its core temperature is high enough to initiate the fusion of deuterium with a proton to form helium-3, but it is thought that it used up all its deuterium fuel long ago.[16] This object has a surface temperature of 950 K.[17]

In March 2014, a super-Neptune mass planet candidate was announced in a much closer-in orbit around GJ 229.[18] Given the proximity to the Sun, the orbit of GJ 229 Ab might be fully characterized by the Gaia space-astrometry mission or via direct imaging. In 2020, a super-Earth mass planet was discovered around GJ 229. GJ 229 Ac orbits the star closer in than GJ 229 Ab, located towards the outer edge but still well inside the star's habitable zone and in that sense similar to Mars in our own Solar System. GJ 229 Ab was not confirmed, but its estimated minimum mass was reduced.[19]

The Gliese 229 planetary system[19][15][5]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
Ac	≥7.268±1.256 M_🜨	0.339±0.011	121.995±0.161	0.19±0.08	—	—
Ab (unconfirmed)	≥8.478±2.033 M_🜨	0.898±0.031	526.115±4.300	0.10±0.06	—	—
B	41.6±3.3[9] M_J	33.3+0.4 −0.3	237.9+5.1 −4.6 y	0.851+0.002 −0.008	7.7+7.6 −4.4°	~1.1[10] R_J

If the planets Gliese 229 Ab & c orbit in the same plane as the brown dwarf Gliese 229 B, their true masses would be significantly greater than their minimum masses, placing them both in the super-Neptune range.[nb 2]

References

Perryman, M. A. C.; et al. (1997). "The Hipparcos Catalogue". Astronomy and Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
Byrne, P. B.; Doyle, J. G.; Menzies, J. W. (May 1, 1985). "Optical photometry and spectroscopy of the flare star Gliese 229 (=HD42581)". Monthly Notices of the Royal Astronomical Society. 214 (2): 119–130. Bibcode:1985MNRAS.214..119B. doi:10.1093/mnras/214.2.119.
Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.
Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
Brandt, G. Mirek; Dupuy, Trent J.; Li, Yiting; Chen, Minghan; Brandt, Timothy D.; Wong, Tin Long Sunny; Currie, Thayne; Bowler, Brendan P.; Liu, Michael C.; Best, William M. J.; Phillips, Mark W. (2021). "Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3". The Astronomical Journal. 162 (6): 301. arXiv:2109.07525. Bibcode:2021AJ....162..301B. doi:10.3847/1538-3881/ac273e. S2CID 237532125.
Morales, J. C.; Ribas, I.; Jordi, C. (February 2008). "The effect of activity on stellar temperatures and radii". Astronomy and Astrophysics. 478 (2): 507–512. arXiv:0711.3523. Bibcode:2008A&A...478..507M. doi:10.1051/0004-6361:20078324. S2CID 16238033. Data from CDS table J/A+A/478/507.
White, Stephen M.; Jackson, Peter D.; Kundu, Mukul R. (December 1989). "A VLA survey of nearby flare stars". Astrophysical Journal Supplement Series. 71: 895–904. Bibcode:1989ApJS...71..895W. doi:10.1086/191401.
Reiners, Ansgar (May 2007). "The narrowest M-dwarf line profiles and the rotation-activity connection at very slow rotation". Astronomy and Astrophysics. 467 (1): 259–268. arXiv:astro-ph/0702634. Bibcode:2007A&A...467..259R. doi:10.1051/0004-6361:20066991. S2CID 8672566.
GJ 229B: Solving the Puzzle of the First Known T-Dwarf with the APOLLO Retrieval Code, 2022, arXiv:2203.11706
Nakajima, T.; Tsuji, T.; Takeda, Y. (July 2015). "Physical Properties of Gliese 229B Based on Newly Determined Carbon and Oxygen Abundances of Gliese 229A". The Astronomical Journal. 150 (2): 53. arXiv:1506.03178. doi:10.1088/0004-6256/150/2/53. ISSN 1538-3881. S2CID 117666443.
Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
Gliese, W. (1969). "Catalogue of Nearby Stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. 22: 1. Bibcode:1969VeARI..22....1G.
"Astronomers Announce First Clear Evidence of a Brown Dwarf". Space Telescope Science Institute news release STScI-1995-48. November 29, 1995. Retrieved 24 September 2013.
Oppenheimer, Ben R. (2014), "Companions of Stars: From Other Stars to Brown Dwarfs to Planets and the Discovery of the First Methane Brown Dwarf", in Joergens, Viki (ed.), 50 Years of Brown Dwarfs - From Prediction to Discovery to Forefront of Research, Astrophysics and Space Science Library, vol. 401, Springer, pp. 81–111, arXiv:1404.4430, doi:10.1007/978-3-319-01162-2_6, ISBN 978-3-319-01162-2, S2CID 118304613
Brandt, Timothy D.; Dupuy, Trent J.; Bowler, Brendan P.; Gagliuffi, Daniella C. Bardalez; Faherty, Jacqueline; Brandt, G. Mirek; Michalik, Daniel (2020). "A Dynamical Mass of 70±5 Jupiter Masses for Gliese 229B, the First Imaged T Dwarf". Astronomical Journal. 160: 4. arXiv:1910.01652. doi:10.3847/1538-3881/abb45e. S2CID 222277091.
J. Kelly Beatty; Carolyn Collins Petersen; Andrew Chaikin (1999). The New Solar System. Cambridge University Press.
Geißler, K.; Chauvin, G.; Sterzik, M. F. (March 2008). "Mid-infrared imaging of brown dwarfs in binary systems". Astronomy and Astrophysics. 480 (1): 193–198. arXiv:0712.1887. Bibcode:2008A&A...480..193G. doi:10.1051/0004-6361:20078229. S2CID 9331798.
Tuomi, Mikko; et al. (2014). "Bayesian search for low-mass planets around nearby M dwarfs – Estimates for occurrence rate based on global detectability statistics". Monthly Notices of the Royal Astronomical Society. 441 (2): 1545. arXiv:1403.0430. Bibcode:2014MNRAS.441.1545T. doi:10.1093/mnras/stu358. S2CID 32965505.
Feng, Fabo; Butler, R. Paul; Shectman, Stephen A.; Crane, Jeffrey D.; Vogt, Steve; Chambers, John; Jones, Hugh R. A.; Wang, Sharon Xuesong; Teske, Johanna K.; Burt, Jenn; Díaz, Matías R.; Thompson, Ian B. (2020). "Search for Nearby Earth Analogs. II. Detection of Five New Planets, Eight Planet Candidates, and Confirmation of Three Planets around Nine Nearby M Dwarfs". The Astrophysical Journal Supplement Series. 246: 11. arXiv:2001.02577. doi:10.3847/1538-4365/ab5e7c. S2CID 210064560.

Notes

Using the absolute visual magnitude of Gliese 229 A $\scriptstyle M_{V_{\ast }}=9.33$ and the absolute visual magnitude of the Sun $\scriptstyle M_{V_{\odot }}=4.83$ , the visual luminosity can be calculated by $\scriptstyle {\frac {L_{V_{\ast }}}{L_{V_{\odot }}}}=10^{0.4\left(M_{V_{\odot }}-M_{V_{\ast }}\right)}$
7.268 M_Earth/sin(13°) = 32.309 M_Earth
8.478 M_Earth/sin(13°) = 37.688 M_Earth

External links

Brown dwarfs (NASA)

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[aaa323-1] Perryman, M. A. C.; et al. (1997). "The Hipparcos Catalogue". Astronomy and Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.

[mnras214-2] Byrne, P. B.; Doyle, J. G.; Menzies, J. W. (May 1, 1985). "Optical photometry and spectroscopy of the flare star Gliese 229 (=HD42581)". Monthly Notices of the Royal Astronomical Society. 214 (2): 119–130. Bibcode:1985MNRAS.214..119B. doi:10.1093/mnras/214.2.119.

[3] Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.

[GaiaEDR3-4] Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.

[Brandt2021-5] Brandt, G. Mirek; Dupuy, Trent J.; Li, Yiting; Chen, Minghan; Brandt, Timothy D.; Wong, Tin Long Sunny; Currie, Thayne; Bowler, Brendan P.; Liu, Michael C.; Best, William M. J.; Phillips, Mark W. (2021). "Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3". The Astronomical Journal. 162 (6): 301. arXiv:2109.07525. Bibcode:2021AJ....162..301B. doi:10.3847/1538-3881/ac273e. S2CID 237532125.

[Morales+2008-6] Morales, J. C.; Ribas, I.; Jordi, C. (February 2008). "The effect of activity on stellar temperatures and radii". Astronomy and Astrophysics. 478 (2): 507–512. arXiv:0711.3523. Bibcode:2008A&A...478..507M. doi:10.1051/0004-6361:20078324. S2CID 16238033. Data from CDS table J/A+A/478/507.

[apjss71-7] White, Stephen M.; Jackson, Peter D.; Kundu, Mukul R. (December 1989). "A VLA survey of nearby flare stars". Astrophysical Journal Supplement Series. 71: 895–904. Bibcode:1989ApJS...71..895W. doi:10.1086/191401.

[aaa467-9] Reiners, Ansgar (May 2007). "The narrowest M-dwarf line profiles and the rotation-activity connection at very slow rotation". Astronomy and Astrophysics. 467 (1): 259–268. arXiv:astro-ph/0702634. Bibcode:2007A&A...467..259R. doi:10.1051/0004-6361:20066991. S2CID 8672566.

[Howe2022-10] GJ 229B: Solving the Puzzle of the First Known T-Dwarf with the APOLLO Retrieval Code, 2022, arXiv:2203.11706

[Nakajima2015-11] Nakajima, T.; Tsuji, T.; Takeda, Y. (July 2015). "Physical Properties of Gliese 229B Based on Newly Determined Carbon and Oxygen Abundances of Gliese 229A". The Astronomical Journal. 150 (2): 53. arXiv:1506.03178. doi:10.1088/0004-6256/150/2/53. ISSN 1538-3881. S2CID 117666443.

[Schmitt-12] Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.

[13] Gliese, W. (1969). "Catalogue of Nearby Stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. 22: 1. Bibcode:1969VeARI..22....1G.

[14] "Astronomers Announce First Clear Evidence of a Brown Dwarf". Space Telescope Science Institute news release STScI-1995-48. November 29, 1995. Retrieved 24 September 2013.

[BenOppenheimer-15] Oppenheimer, Ben R. (2014), "Companions of Stars: From Other Stars to Brown Dwarfs to Planets and the Discovery of the First Methane Brown Dwarf", in Joergens, Viki (ed.), 50 Years of Brown Dwarfs - From Prediction to Discovery to Forefront of Research, Astrophysics and Space Science Library, vol. 401, Springer, pp. 81–111, arXiv:1404.4430, doi:10.1007/978-3-319-01162-2_6, ISBN 978-3-319-01162-2, S2CID 118304613

[Brandt2019-16] Brandt, Timothy D.; Dupuy, Trent J.; Bowler, Brendan P.; Gagliuffi, Daniella C. Bardalez; Faherty, Jacqueline; Brandt, G. Mirek; Michalik, Daniel (2020). "A Dynamical Mass of 70±5 Jupiter Masses for Gliese 229B, the First Imaged T Dwarf". Astronomical Journal. 160: 4. arXiv:1910.01652. doi:10.3847/1538-3881/abb45e. S2CID 222277091.

[17] J. Kelly Beatty; Carolyn Collins Petersen; Andrew Chaikin (1999). The New Solar System. Cambridge University Press.

[geibler-18] Geißler, K.; Chauvin, G.; Sterzik, M. F. (March 2008). "Mid-infrared imaging of brown dwarfs in binary systems". Astronomy and Astrophysics. 480 (1): 193–198. arXiv:0712.1887. Bibcode:2008A&A...480..193G. doi:10.1051/0004-6361:20078229. S2CID 9331798.

[uves_harps-19] Tuomi, Mikko; et al. (2014). "Bayesian search for low-mass planets around nearby M dwarfs – Estimates for occurrence rate based on global detectability statistics". Monthly Notices of the Royal Astronomical Society. 441 (2): 1545. arXiv:1403.0430. Bibcode:2014MNRAS.441.1545T. doi:10.1093/mnras/stu358. S2CID 32965505.

[Feng2020-20] Feng, Fabo; Butler, R. Paul; Shectman, Stephen A.; Crane, Jeffrey D.; Vogt, Steve; Chambers, John; Jones, Hugh R. A.; Wang, Sharon Xuesong; Teske, Johanna K.; Burt, Jenn; Díaz, Matías R.; Thompson, Ian B. (2020). "Search for Nearby Earth Analogs. II. Detection of Five New Planets, Eight Planet Candidates, and Confirmation of Three Planets around Nine Nearby M Dwarfs". The Astrophysical Journal Supplement Series. 246: 11. arXiv:2001.02577. doi:10.3847/1538-4365/ab5e7c. S2CID 210064560.

[luminosity_visual-8] Using the absolute visual magnitude of Gliese 229 A $\scriptstyle M_{V_{\ast }}=9.33$ and the absolute visual magnitude of the Sun $\scriptstyle M_{V_{\odot }}=4.83$ , the visual luminosity can be calculated by $\scriptstyle {\frac {L_{V_{\ast }}}{L_{V_{\odot }}}}=10^{0.4\left(M_{V_{\odot }}-M_{V_{\ast }}\right)}$

[21] 7.268 M_Earth/sin(13°) = 32.309 M_Earth
8.478 M_Earth/sin(13°) = 37.688 M_Earth

Observation data Epoch J2000 Equinox J2000
Gliese 229 A and B.
Constellation	Lepus
Right ascension	06^h 10^m 34.6154^s[1]
Declination	−21° 51′ 52.715″[1]
Apparent magnitude (V)	8.14
Characteristics
Evolutionary stage	Main sequence / Brown dwarf
Spectral type	M1Ve / T7V[2]
U−B color index	+1.222[2]
B−V color index	+1.478[2]
Variable type	Flare star
Astrometry

Radial velocity (R_v)	+3.9[3] km/s
Proper motion (μ)	RA: –137.01[1] mas/yr Dec.: –714.05[1] mas/yr
Parallax (π)	173.5740 ± 0.0170 mas[4]
Distance	18.791 ± 0.002 ly (5.7612 ± 0.0006 pc)
Absolute magnitude (M_V)	9.326[5]
Absolute bolometric magnitude (M_bol)	7.96[6]

Orbit[5]
Companion	Gliese 229 B
Period (P)	237.9+5.1 −4.6 yr
Semi-major axis (a)	33.3+0.4 −0.3 AU
Eccentricity (e)	0.851+0.002 −0.008
Inclination (i)	7.7+7.6 −4.4°
Longitude of the node (Ω)	−29+13 −140°
Periastron epoch (T)	2466912+97 −63
Argument of periastron (ω) (secondary)	−9+140 −13°
Details
A
Mass	0.579[5] `M`_☉
Radius	0.69[7] `R`_☉
Luminosity (bolometric)	0.0430[5] `L`_☉
Luminosity (visual, L_V)	0.0158[nb 1] `L`_☉
Temperature	3,700[6] K
Rotational velocity (v sin i)	1[8] km/s
B
Mass	41.6±3.3[9] M_Jup
Radius	~1.1[10] R_Jup
Luminosity (bolometric)	~0.000011 `L`_☉
Temperature	869⁺⁵ ₋₇[9] K
Other designations
BD-21°1377, HD 42581, HIP 29295, LHS 1827, NSV 2863, SAO 171334, TYC 5945- 765-1
Database references
SIMBAD	A
	B
Gliese 229 Location of Gliese 229 in the constellation Lepus