View source for GJ 3929

{{Short description|Red dwarf star in the constellation Corona Borealis}}
{{Starbox begin
|name=GJ 3929
}}
{{Starbox image
|image=[[File:Gliese 3929 system.jpg|thumb|300px]]
|caption=Artist's impression and size comparison of the two planets in the GJ 3929 system with Earth
}}
{{Starbox observe
|epoch=J2000
|constell=[[Corona Borealis]]{{Efn|Obtained with a right ascension of {{RA|15|58|18.8}} and a declination of {{DEC|+35|24|24.3}}<ref name=":5a" /> on this  [https://djm.cc/constellation.html website].|name=Constellation|group=note}}
|pronounce=
|ra={{RA|15|58|18.8}}<ref name=":5a">{{Cite web |title=G 180-18 |url=https://simbad.cds.unistra.fr/mobile/object.html?object_name=G%20180-18 |access-date=January 4, 2023 |website=SIMBAD}}</ref>
|dec={{DEC|+35|24|24.3}}<ref name=":5a" />
|appmag_v=12.67<ref name=":6" />}}
{{Starbox character
|class=M3.5V<ref name=":5a" />
}}
{{Starbox astrometry
|radial_v={{val|10.14}}<ref name=":6" />
|prop_mo_ra={{val|-143.277|0.066}}
|prop_mo_dec={{val|318.219|0.082}}
|parallax=63.1727
|p_error=0.038
|parallax_footnote=<ref name=":5a" />
|absmag_v=11
|dist_pc={{val|15.822|0.006}}
|dist_ly={{val|51.58|0.02}}
|dist_footnote=<ref name=":2" />
|pm_footnote=<ref name=":6"/>
}}
{{Starbox detail
|mass={{Val|0.313|0.027|0.022}}
|metal_fe={{val|-0.02|0.12}}
|radius={{val|0.32|0.01}}
|rotational_velocity={{val|2|p=<}}
|luminosity={{val|0.0109|0.0005|0.0004}}
|temperature={{val|3384|88|fmt=commas}}
|gravity={{val|4.89|0.05}}
|age_gyr=2.2 – 11.2{{efn|The quoted value of {{val|7.1|4.1|4.9}} has very high margins of error.|name=Error|group=note}}
|source=<ref name=":2" />
|rotation={{val|122|13|ul=day}}<ref name=":1" />
}}
{{Starbox catalog
|names=[[Tess object of interest|TOI]]-2013, [[TESS Input Catalog|TIC]] 188589164, [[2MASS]] J15581883+3524236, [[Gaia DR3]] 1372215976327300480,<ref name=":2" /> [[Giclas|G]] 180-18<ref name=":0" />
}}
{{Starbox reference
|Simbad=G+180-18
|ARICNS=
}}
{{Starbox end}}
'''GJ 3929''', also known as Gliese 3929 and TOI-2013, is a [[red dwarf]] star located 51.6 [[light-year]]s from Earth, in the constellation [[Corona Borealis]].<ref name=":0">{{Cite web |title=★ Gliese 3929 |url=https://www.stellarcatalog.com/stars/gliese-3929 |access-date=2024-01-01 |website=Stellar Catalog |language=en}}</ref>{{Efn|Obtained with a right ascension of {{RA|15|58|18.8}} and a declination of {{DEC|+35|24|24.3}}<ref name=":5a" /> on this  [https://djm.cc/constellation.html website].|name=Constellation 1|group=note}} With an [[apparent magnitude]] of 12,<ref name=":0" /> it is not visible to the naked eye. In 2022, two exoplanets were detected orbiting the star.<ref name=":1">{{Cite journal |last1=Kemmer |first1=J. |last2=Dreizler |first2=S. |last3=Kossakowski |first3=D. |last4=Stock |first4=S. |last5=Quirrenbach |first5=A. |last6=Caballero |first6=J. A. |last7=Amado |first7=P. J. |last8=Collins |first8=K. A. |last9=Espinoza |first9=N. |last10=Herrero |first10=E. |last11=Jenkins |first11=J. M. |last12=Latham |first12=D. W. |last13=Lillo-Box |first13=J. |last14=Narita |first14=N. |last15=Pallé |first15=E. |date=2022-03-01 |title=Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b |url=https://www.aanda.org/articles/aa/abs/2022/03/aa42653-21/aa42653-21.html |journal=Astronomy & Astrophysics |language=en |volume=659 |pages=A17 |doi=10.1051/0004-6361/202142653 |arxiv=2202.00970 |bibcode=2022A&A...659A..17K |issn=0004-6361}}</ref>
== Characteristics ==
GJ 3929 is a [[red dwarf]] of [[spectral type]] M3.5V, having a radius of {{val|0.32|0.01|ul=Solar radius}}, a mass of {{val|0.313 |0.027|0.022|ul=Solar mass}} and a temperature of {{Val|3384|88|ul=K}}.<ref name=":7" /> With an [[apparent magnitude]] of 12.7,<ref name=":6">{{Cite web |title=GJ 3929 {{!}} NASA Exoplanet Archive |url=https://exoplanetarchive.ipac.caltech.edu/overview/GJ%203929 |access-date=2024-01-03 |website=exoplanetarchive.ipac.caltech.edu}}</ref> it cannot be visible with the naked eye, neither with a small telescope.<ref name=":0" /> It has no [[companion star]]s.<ref name=":1" /> The age of GJ 3929 is estimated at 2.2 to 12.2 billion years.<ref name=":2" />
The star is located in the [[Northern celestial hemisphere|northern hemisphere]], approximately 50 [[Light-year|light years]] from Earth,<ref name=":0" /> in the direction of the constellation [[Corona Borealis]].{{Efn|Obtained with a right ascension of {{RA|15|58|18.8}} and a declination of {{DEC|+35|24|24.3}}<ref name=":5a" /> on this  [https://djm.cc/constellation.html website].|name=Constellation 2|group=}} Its closest neighbor is the red dwarf G 179–57, located at a distance of 3.9 light years.<ref name=":0" />
{|class="wikitable unsortable"
|+Nearest stars to GJ 3929<ref name=":0" />
!Name
!Distance {{nowrap|(light-years)}}
|-
|G 179-57
|3.9
|-
|[[LHS 3154|LP 224-38]]
|5.2
|-
|[[Ross 640]]
|5.6
|-
|[[Rho Coronae Borealis]]
|5.9
|-
|[[Gliese 611]]
|5.9
|}
== Planetary system ==
In 2022, two exoplanets were detected orbiting around GJ 3929.<ref name=":1" /> The innermost, GJ 3929 b, is a [[rocky planet]] just 9% larger than Earth, while the outermost, GJ 3929 c, is a [[sub-Neptune]] with 5.7 times the mass of Earth.<ref name=":2">{{Cite journal |last1=Beard |first1=Corey |last2=Robertson |first2=Paul |last3=Kanodia |first3=Shubham |last4=Lubin |first4=Jack |last5=Cañas |first5=Caleb I. |last6=Gupta |first6=Arvind F. |last7=Holcomb |first7=Rae |last8=Jones |first8=Sinclaire |last9=Libby-Roberts |first9=Jessica E. |last10=Lin |first10=Andrea S. J. |last11=Mahadevan |first11=Suvrath |last12=Stefánsson |first12=Guðmundur |last13=Bender |first13=Chad F. |last14=Blake |first14=Cullen H. |last15=Cochran |first15=William D. |date=2022-09-01 |title=GJ 3929: High Precision Photometric and Doppler Characterization of an Exo-Venus and its Hot, Mini-Neptune-mass Companion |journal=The Astrophysical Journal |volume=936 |issue=1 |pages=55 |doi=10.3847/1538-4357/ac8480 |doi-access=free |arxiv=2207.10672 |bibcode=2022ApJ...936...55B |issn=0004-637X}}</ref> Both planets orbit below the star's [[habitable zone]].<ref name=":7">{{Cite web |title=Open Exoplanet Catalogue - GJ 3929 b |url=https://www.openexoplanetcatalogue.com/planet/GJ%203929%20b/ |access-date=2024-01-02 |website=www.openexoplanetcatalogue.com}}</ref>
{{OrbitboxPlanet begin|table_ref=<ref name=":2" />|name=GJ 3929}}
{{OrbitboxPlanet|exoplanet=[[GJ 3929 b|b]]|mass_earth={{val|1.75|0.45}}|radius_earth={{val|1.09|0.04}}|period={{val|2.616}}|semimajor={{val|0.0252|0.0005}}|inclination={{Nowrap|88.442°{{±|0.008}}}}|eccentricity=0 (fixed)}}
{{OrbitboxPlanet|exoplanet=c|mass_earth=>{{val|5.71|0.94}}|radius_earth=|period={{val|15.04|0.03}}|semimajor={{val|0.081|0.002}}|inclination=|eccentricity=0 (fixed)}}
{{Orbitbox end}}
=== GJ 3929 b ===
{{Main article|GJ 3929 b}}
The innermost planet, [[GJ 3929 b]] (TOI-2013 b), is an [[Exoplanet#Earth-size planets|Earth-sized planet]] discovered by the [[transit method]].<ref name=":1" /> Orbiting its star at a distance of {{Convert|0.0252|AU|km}}, the planet is located in its star's [[Venus zone]], and completes a revolution every 2 days and 15 hours.<ref name=":2" /> The planet's [[equilibrium temperature]] is calculated at {{Convert|568|K|C}}, and it receives a [[Solar irradiance|planetary insolation]] 17 times greater than what the Earth receives from the Sun.<ref name=":2" />
The planet's mass is calculated at {{val|1.75|0.45|ul=Earth mass}} according to photometric observations using the [[WIYN Observatory#Current instrumentation|NEID spectrometer]].<ref name=":2" /> Observations using the [[ARCTIC imager]], plus [[Photometry (astronomy)|photometry]] from [[TESS]] and [[LCOGT]], constrained the planet's radius to {{val|1.09|0.04|ul=Earth radius}}.<ref name=":2" /> This radius makes GJ 3929 b very similar to Earth in terms of size.
Due to the apparent brightness of the host star, and its small size, GJ 3929 b is an excellent planet for atmospheric study with the [[James Webb Space Telescope]].<ref name=":2" /><ref name=":1" />
It was discovered by a team of astronomers led by Jonas Kemmer.<ref name=":5">{{Cite web |title=Hot Earth-sized exoplanet detected with TESS |url=https://phys.org/news/2022-02-hot-earth-sized-exoplanet-tess.html |access-date=2024-01-04 |website=phys.org |language=en}}</ref> They reported an [[planetary transit]] signal in the host star's [[light curve]].<ref name=":5" /> Subsequent observations, mainly with the [[CARMENES (spectrograph)|CARMENES]] [[spectrograph]], revealed that this transit signal is an orbiting exoplanet.<ref name=":5" /><ref name=":1" />
=== {{vanchor|GJ 3929 c}} ===
The outermost planet, GJ 3929 c (TOI-2013 c) is a [[Sub-Neptune]] discovered using the [[Radial velocity method|radial velocity]] method.<ref name=":1" /> It orbits its star at a distance of {{Convert|0.081|AU|km}}, 3 times further away than {{Nowrap|GJ 3929 b}}, but still below GJ 3929's [[habitable zone]],<ref name=":7" /> completing an orbit every 15 days.<ref name=":2" />
Its [[minimum mass]] is {{val|5.71|0.94|ul=Earth mass}}, while its radius is unknown.<ref name=":2" /> Estimates using mass-radius relationship derive a radius of 2.26 {{Earth radius|link=Y}}.<ref name=":2" /> Its [[equilibrium temperature]] is calculated at {{Convert|317|K|C}}, and it receives a [[Solar irradiance|planetary insolation]] 68% greater than what the Earth receives from the Sun.<ref name=":2" />
GJ 3929 c was first identified in [[Radial velocity method|radial velocity]] data, which indicated the existence of another planet besides GJ 3929 b.<ref name=":1" /><ref name=":8">{{Cite web |last=Cassese |first=Ben |date=2022-12-09 |title=Dotting the i's, Crossing the t's: Follow-Up of an Exo-Venus |url=https://aasnova.org/2022/12/09/dotting-the-is-crossing-the-ts-follow-up-of-an-exo-venus/ |access-date=2024-01-04 |website=AAS Nova |language=en-US}}</ref> Initially, it was just an exoplanet candidate, but it was later confirmed by a team led by Corey Beard.<ref name=":2" /><ref name=":8" /> Because its [[orbital period]] (15 days) is far from its star's [[Rotation period (astronomy)|rotation period]] (122 days), it is unlikely that the radial velocity signal is actually an artifact of its parent star's activity and rotation.<ref name=":1" />
== See also ==
* [[Gliese 436]]
== Notes and references ==
<references />
<references group="lower-alpha" />
<references group="note" />
{{2022 in space}}
{{Corona Borealis}}
[[Category:Gliese and GJ objects|3929]]
[[Category:M-type main-sequence stars]]
[[Category:Corona Borealis]]
[[Category:Planetary systems with two confirmed planets]]
[[Category:TIC objects|188589164]]
[[Category:2MASS objects|J15581883+3524236]]