View source for Astronomy:Gliese 784

{{Sky|20|13|53.396|-|45|09|50.47|20.106}}
{{short description|Star in the constellation Telescopium}}
{{Starbox begin}}
{{Starbox observe
 | epoch       = [[Astronomy:J2000.0|J2000.0]]
 | constell    = [[Astronomy:Telescopium|Telescopium]]
 | ra          = {{RA|20|13|53.396}}<ref name=EDR3/>
 | dec         = {{DEC|-45|09|50.47}}<ref name=EDR3/>
 | appmag_v    = 7.96<ref name=Torres_et_al_2006/>
}}
{{Starbox character
 | type        = 
 | class       = M0V<ref name=Torres_et_al_2006/>
 | b-v         = 1.45<ref name=Torres_et_al_2006/>
 | v-i         = 1.82<ref name=Torres_et_al_2006/>
 | u-b         = 
 | variable    = 
}}
{{Starbox astrometry
 | radial_v    = −33.5{{±|0.5}}<ref name=EDR3/>
 | prop_mo_ra  = 778.331
 | prop_mo_dec = -159.939
 | pm_footnote = <ref name=EDR3/>
 | parallax    = 162.2171
 | p_error     = 0.0225
 | parallax_footnote = <ref name=EDR3/>
 | absmag_v    = 9.01<ref name=Anderson_Francis_2012/>
}}
{{Starbox detail
 | source      = 
 | mass        = 0.58<ref name=RECONS/>
 | radius      = 0.58<ref name=Gáspár_et_al_2016/>
 | luminosity  = 0.06<ref name=Gáspár_et_al_2016/>
 | gravity     = 
 | temperature = 3,754{{±|92}}<ref name=Hojjatpanah_et_al_2019/>
 | metal_fe    = −0.07{{±|0.06}}<ref name=Hojjatpanah_et_al_2019/>
 | rotation    = 48{{±|12}}<ref name=Byrne_Doyle_1989/>
 | rotational_velocity = 1.0<ref name=Torres_et_al_2006/>
 | age_gyr     = 0.85{{±|0.4}}<ref name=Brems2019/>
}}
{{Starbox catalog
 | names = {{odlist | CD=-45 13677 | Ci 20=1196 | HD=191849 | LHS=3531 | LFT=1532 | LPM=730 | LTT=7999 | SAO=230110 | NLTT=48880 | PM=20103-4519 | PPM=325963 | PLX=4794 | HIP=99701 | TYC=8392-2673-1 | 2MASS=J20135335-4509506 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad = Gliese+784
}}
{{Starbox image
|image={{Location map|100x100|AlternativeMap=Telescopium_constellation_map.svg
|alt=Gliese 784 is located in the constellation Telescopium
|caption=Location of Gliese 784 in the constellation [[Astronomy:Telescopium|Telescopium]]|border=infobox|mark=Red_pog.png|width=300
|label=Gliese 784
|position=bottom
|lat=76.9
|long=11.1
}}|caption=
}}
{{Starbox end}}

'''Gliese 784''' is a single<ref name=Brems2019/> [[Astronomy:Red dwarf|red dwarf]] star located in the southern [[Astronomy:Constellation|constellation]] of [[Astronomy:Telescopium|Telescopium]] that may host an [[Astronomy:Exoplanet|exoplanet]]ary companion. The star was catalogued in 1900, when it was included in the ''Cordoba Durchmusterung (CD)'' by [[Biography:John M. Thome|John M. Thome]] with the designation '''CD−45 13677'''.<ref name="Thome1900"/> It is too faint to be viewed with the naked eye, having an [[Astronomy:Apparent visual magnitude|apparent visual magnitude]] of 7.96.<ref name=Torres_et_al_2006/> Gliese 784 is located at a distance of 20.1&nbsp;[[Astronomy:Light-year|light-year]]s from the [[Astronomy:Sun|Sun]] as determined from [[Astronomy:Stellar parallax|parallax]] measurements, and is drifting closer with a [[Astronomy:Radial velocity|radial velocity]] of −33.5&nbsp;km/s.<ref name=EDR3/> The system is predicted to come as close as {{convert|3.5047|pc|ly|1|disp=out|abbr=off}} in ~121,700&nbsp;years time.<ref name=Bailer_et_al_2018/>

This is a small M-type main-sequence star with a [[Astronomy:Stellar classification|stellar classification]] of M0V.<ref name=Torres_et_al_2006/> It is much younger than Sun at 0.85{{±|0.4}} billion years.<ref name=Brems2019/> Despite this, it appears to be rotating slowly with a [[Rotation period|period]] of roughly 48&nbsp;days.<ref name=Byrne_Doyle_1989/> The star has 58% of the mass and 58% of the radius of the Sun. It is radiating just 6%<ref name=Gáspár_et_al_2016/> of the luminosity of the Sun from its [[Astronomy:Photosphere|photosphere]] at an [[Astronomy:Effective temperature|effective temperature]] of 3,754&nbsp;K.<ref name=Hojjatpanah_et_al_2019/>

==Planetary system == 

In June 2019 one planet candidate was reported in orbit around Gliese 784.<ref name=Tuomi_et_al_2019/> Since 2020, the star is suspected to be surrounded by a disk of cold dust, but the signal may be also due to a background extragalactic source.<ref name=Tanner_et_al_2020/>

{{OrbitboxPlanet begin
 | table_ref = <ref name=Tuomi_et_al_2019/>
}}
{{OrbitboxPlanet hypothetical
 | exoplanet = [[Astronomy:Gliese 784 b|b]]
 | mass_earth = {{val|9.4|4.6|4.1}}
 | period = {{val|6.6592|0.0033|0.0038}}
 | semimajor = 0.059 ± 0.006
 | eccentricity = {{val|0.05|0.23|0.05}}
 | inclination =
}}
{{Orbitbox end}}

==References==
{{reflist|refs=

<ref name=EDR3>{{cite Gaia EDR3 | 6673000841376349696}}</ref>

<ref name=SIMBAD>{{cite simbad
 | title=HD 191849 | access-date=2021-11-22 }}</ref>

<ref name=Anderson_Francis_2012>{{cite journal
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | title=XHIP: An extended hipparcos compilation
 | journal=Astronomy Letters
 | volume=38 | issue=5 | pages=331 | year=2012
 | bibcode=2012AstL...38..331A | arxiv=1108.4971
 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>

<ref name=Torres_et_al_2006>{{cite journal
 | title=Search for associations containing young stars (SACY). I. Sample and searching method
 | last1=Torres | first1=C. A. O. | last2=Quast | first2=G. R.
 | last3=Da Silva | first3=L. | last4=De La Reza | first4=R.
 | last5=Melo | first5=C. H. F. | last6=Sterzik | first6=M.
 | display-authors=1 | journal=Astronomy and Astrophysics
 | volume=460 | issue=3 | date=December 2006 | pages=695–708
 | doi=10.1051/0004-6361:20065602 | arxiv=astro-ph/0609258
 | bibcode=2006A&A...460..695T | s2cid=16080025 }}</ref>

<ref name="Thome1900">{{cite journal
 | title=Cordoba Durchmusterung declination -42 to -52
 | year=1900
 | journal=Resultados del Observatorio Nacional Argentino
 | volume=18 | pages=1–502
 | bibcode=1900RNAO...18....1T }} (See also
 [http://adsabs.harvard.edu/abs/1900RNAO...18....1. 1900RNAO...18....1.],
 [http://adsabs.harvard.edu/abs/1900RNAO...18.....T 1900RNAO...18.....T]).
 [http://cdsads.u-strasbg.fr/full/seri/RNAO./0018//0000265.000.html Page 206 (CD-45 13677)]</ref>

<ref name=Brems2019>{{citation
 | title=Radial-velocity jitter of stars as a function of observational timescale and stellar age
 | display-authors=1 | last1=Brems | first1=Stefan S.
 | last2=Kürster | first2=Martin | last3=Trifonov | first3=Trifon
 | last4=Reffert | first4=Sabine | last5=Quirrenbach | first5=Andreas
 | journal=Astronomy & Astrophysics
 | volume=632 | pages=A37 | year=2019
 | doi=10.1051/0004-6361/201935520 | arxiv=1910.10389
 | bibcode=2019A&A...632A..37B | s2cid=204838030}}</ref>

<ref name=Tanner_et_al_2020>{{citation
 | title=Herschel Observations of Disks around Late-type Stars
 | last1=Tanner | first1=Angelle | last2=Plavchan | first2=Peter
 | last3=Bryden | first3=Geoff | last4=Kennedy | first4=Grant
 | last5=Matrá | first5=Luca | last6=Cronin-Coltsmann | first6=Patrick
 | last7=Lowrance | first7=Patrick | last8=Henry | first8=Todd
 | last9=Riaz | first9=Basmah | last10=Gizis | first10=John E.
 | last11=Riedel | first11=Adric | last12=Choquet | first12=Elodie
 | display-authors=1 | journal=Publications of the Astronomical Society of the Pacific
 | volume=132 | issue=1014 | page=084401 | year=2020
 | doi=10.1088/1538-3873/ab895f | arxiv=2004.12597
 | bibcode=2020PASP..132h4401T|s2cid=216553868 }}</ref>

<ref name=RECONS>{{cite web
 | url=http://www.recons.org/TOP100.posted.htm
 | title=The One Hundred Nearest Star Systems
 | publisher=Research Consortium On Nearby Stars
 | website=RECONS | date=January 1, 2012 }}</ref>

<ref name=Tuomi_et_al_2019>{{Cite arXiv
 | title=Frequency of planets orbiting M dwarfs in the Solar neighbourhood
 | display-authors=1 | last1=Tuomi | first1=M.
 | last2=Jones | first2=H. R. A. | last3=Butler | first3=R. P.
 | last4=Arriagada | first4=P. | last5=Vogt | first5=S. S.
 | last6=Burt | first6=J. | last7=Laughlin | first7=G.
 | last8=Holden | first8=B. | last9=Shectman | first9=S. A.
 | last10=Crane | first10=J. D. | last11=Thompson | first11=I.
 | last12=Keiser | first12=S. | last13=Jenkins | first13=J. S.
 | last14=Berdiñas | first14=Z. | last15=Diaz | first15=M.
 | last16=Kiraga | first16=M. | last17=Barnes | first17=J. R.
 | date=2019-06-11 | eprint=1906.04644v1
 | language=en | class=astro-ph.EP }}</ref>

<ref name=Hojjatpanah_et_al_2019>{{cite journal
 | title=Catalog for the ESPRESSO blind radial velocity exoplanet survey
 | last1=Hojjatpanah | first1=S. | last2=Figueira | first2=P.
 | last3=Santos | first3=N. C. | last4=Adibekyan | first4=V.
 | last5=Sousa | first5=S. G. | last6=Delgado-Mena | first6=E.
 | last7=Alibert | first7=Y. | last8=Cristiani | first8=S.
 | last9=González Hernández | first9=J. I. | last10=Lanza | first10=A. F.
 | last11=Di Marcantonio | first11=P. | last12=Martins | first12=J. H. C.
 | last13=Micela | first13=G. | last14=Molaro | first14=P.
 | last15=Neves | first15=V. | last16=Oshagh | first16=M.
 | last17=Pepe | first17=F. | last18=Poretti | first18=E.
 | last19=Rojas-Ayala | first19=B. | last20=Rebolo | first20=R.
 | last21=Suárez Mascareño | first21=A. | last22=Zapatero Osorio | first22=M. R.
 | display-authors=1 | journal=Astronomy & Astrophysics
 | volume=629 | pages=A80 | year=2019
 | arxiv=1908.04627 | doi=10.1051/0004-6361/201834729
 | bibcode=2019A&A...629A..80H |s2cid=199552090 }}</ref>

<ref name=Bailer_et_al_2018>{{cite journal
 | title=New stellar encounters discovered in the second Gaia data release
 | last1=Bailer-Jones | first1=C.A.L. | last2=Rybizki | first2=J.
 | last3=Andrae | first3=R. | last4=Fouesnea | first4=M.
 | display-authors=1 | journal=Astronomy & Astrophysics
 | volume=616 | pages=A37 | date=2018
 | arxiv=1805.07581 | bibcode=2018A&A...616A..37B
 | doi=10.1051/0004-6361/201833456 | s2cid=56269929 }}</ref>

<ref name=Gáspár_et_al_2016>{{cite journal
 | display-authors=1 | last1=Gáspár | first1=András
 | last2=Rieke | first2=George H. | last3=Ballering | first3=Nicholas
 | title=The Correlation between Metallicity and Debris Disk Mass
 | journal=The Astrophysical Journal
 | volume=826 | issue=2 | pages=171 | year=2016
 | bibcode=2016ApJ...826..171G | arxiv=1604.07403
 | doi=10.3847/0004-637X/826/2/171 | s2cid=119241004 | doi-access=free }}</ref>

<ref name=Byrne_Doyle_1989>{{cite journal
 | title=Activity in late-type dwarfs. III. Chromospheric and transition region line fluxes for two dM stars
 | last1=Byrne | first1=P. B. | last2=Doyle | first2=J. G.
 | journal=Astronomy and Astrophysics
 | volume=208 | pages=159–165 | date=January 1989
 | bibcode=1989A&A...208..159B }}</ref>

}}

{{Stars of Telescopium}}

<!-- Properties -->
[[Category:M-type main-sequence stars]]
[[Category:Hypothetical planetary systems]]
[[Category:Circumstellar disks]]
<!-- Other -->
[[Category:2MASS objects|J20135335-4509506]]
[[Category:Durchmusterung objects|CD-45 13677]]
[[Category:Gliese and GJ objects|0784]]
[[Category:Henry Draper Catalogue objects|191849]]
[[Category:Hipparcos objects|099701]]

{{Sourceattribution|Gliese 784}}