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WASP-84

{{Short description|Star in the constellation Hydra}}

{{Starbox begin}}

{{Starbox observe

| epoch = J2000

| constell = Hydra

| ra = {{RA|08|44|25.70315}}

| dec = {{DEC|+01|51|36.1055}}

| appmag_v = 10.83

}}

{{Starbox character

| type = main sequence

| class = G9V

}}

{{Starbox astrometry

| radial_v = {{val|−11.63|0.21}}

| prop_mo_ra = −23.344

| prop_mo_dec = −31.570

| pm_footnote =

| parallax = 9.9636

| p_error = 0.0149

| parallax_footnote =

}}

{{Starbox detail

| mass = 0.842{{±|0.037|0.036}}

| radius = 0.748{{±|0.015}}

| temperature = 5350{{±|31}}

| luminosity = 0.48

| gravity = 4.63{{±|0.06}}

| metal_fe = 0.05{{±|0.02}}

| rotation = 14.36{{±|0.35}} d

| rotational_velocity = 4.10{{±|0.30}}

| age_gyr = 8.5{{±|4.1|5.5}}

}}

{{Starbox catalog

| names = {{odlist|2MASS = J08442570+0151361 | BD = +02 2056 |Gaia DR2=3078836109158636928|WASP=84|TYC=211-706-1|GSC=00211-00706}}

}}

{{Starbox reference

| Simbad = WASP-84

}}

{{Starbox end}}

WASP-84, also known as BD+02 2056, is a G-type main-sequence star {{convert|327|ly|pc|lk=on|abbr=off}} away in the constellation Hydra. Its surface temperature is 5350{{±|31}} K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05{{±|0.02}}. It is rich in carbon and depleted of oxygen. WASP-84's age is probably older than the Sun at 8.5{{±|4.1|5.5}} billion years. The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.{{citation |arxiv=1503.09111 |doi=10.1051/0004-6361/201525774 |title=Comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars |year=2015 |last1=Maxted |first1=P. F. L. |last2=Serenelli |first2=A. M. |last3=Southworth |first3=J. |journal=Astronomy & Astrophysics |volume=577 |pages=A90 |bibcode=2015A&A...577A..90M |s2cid=53324330 }}

A multiplicity survey did not detect any stellar companions to WASP-84 as of 2015.{{citation |arxiv=1506.05456 |doi=10.1051/0004-6361/201526525 |title=A Lucky Imaging search for stellar sources near 74 transit hosts |year=2015 |last1=Wöllert |first1=Maria |last2=Brandner |first2=Wolfgang |journal=Astronomy & Astrophysics |volume=579 |pages=A129 |bibcode=2015A&A...579A.129W |s2cid=118903879 }}

Planetary system

In 2013, one exoplanet, named WASP-84b, was discovered on a tight, circular orbit. The planet is a hot Jupiter that cannot have formed in its current location and likely migrated from elsewhere. The planetary orbit is well aligned with the equatorial plane of the star, misalignment being equal to 0.3{{±|1.7}}°. Planetary equilibrium temperature is 832{{±|13}} K.

In 2023, a second planet was discovered around WASP-84. This appears to be a dense rocky planet despite its high mass, comparable to Uranus.

{{OrbitboxPlanet begin

| name = WASP-84

| table_ref =

}}

{{OrbitboxPlanet

| exoplanet = c

| mass_earth = {{val|15.2|4.5|4.2}}

| radius_earth = {{val|1.95|0.12}}

| semimajor = {{val|0.02359|0.00100}}

| period = {{val|1.4468849|0.0000022|0.0000016}}

| eccentricity =

| inclination = {{val|83.20|0.51|0.49}}

}}

{{OrbitboxPlanet

| exoplanet = b

| mass = {{val|0.692|0.058}}

| radius = {{val|0.956|0.024}}

| semimajor = {{val|0.0778|0.0021}}

| period = {{val|8.52349648|(60)}}

| eccentricity = <0.077

| inclination = {{val|88.292|0.045|0.042}}

}}

{{Orbitbox end}}

References

{{Reflist|refs=

{{cite simbad|title=BD+02 2056|access-date=2021-01-25}}

{{cite Gaia DR3|3078836109158636928}}

{{citation |arxiv=1310.5654 |doi=10.1093/mnras/stu1737 |title=Three newly discovered sub-Jupiter-mass planets: WASP-69b and WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary |year=2014 |last1=Anderson |first1=D. R. |last2=Collier Cameron |first2=A. |last3=Delrez |first3=L. |last4=Doyle |first4=A. P. |last5=Faedi |first5=F. |last6=Fumel |first6=A. |last7=Gillon |first7=M. |last8=Gómez Maqueo Chew |first8=Y. |last9=Hellier |first9=C. |last10=Jehin |first10=E. |last11=Lendl |first11=M. |last12=Maxted |first12=P. F. L. |last13=Pepe |first13=F. |last14=Pollacco |first14=D. |last15=Queloz |first15=D. |last16=Ségransan |first16=D. |last17=Skillen |first17=I. |last18=Smalley |first18=B. |last19=Smith |first19=A. M. S. |last20=Southworth |first20=J. |last21=Triaud |first21=A. H. M. J. |last22=Turner |first22=O. D. |last23=Udry |first23=S. |last24=West |first24=R. G. |journal=Monthly Notices of the Royal Astronomical Society |volume=445 |issue=2 |pages=1114–1129 |doi-access=free |s2cid=54750890 |bibcode=2014MNRAS.445.1114A}}

{{citation |arxiv=1409.6335 |doi=10.1088/2041-8205/800/1/L9 |title=THE WELL-ALIGNED ORBIT OF WASP-84b: EVIDENCE FOR DISK MIGRATION OF a HOT JUPITER |year=2015 |last1=Anderson |first1=D. R. |last2=Triaud |first2=A. H. M. J. |last3=Turner |first3=O. D. |last4=Brown |first4=D. J. A. |last5=Clark |first5=B. J. M. |last6=Smalley |first6=B. |last7=Cameron |first7=A. Collier |last8=Doyle |first8=A. P. |last9=Gillon |first9=M. |last10=Hellier |first10=C. |last11=Lovis |first11=C. |last12=Maxted |first12=P. F. L. |last13=Pollacco |first13=D. |last14=Queloz |first14=D. |last15=Smith |first15=A. M. S. |journal=The Astrophysical Journal |volume=800 |issue=1 |pages=L9 |bibcode=2015ApJ...800L...9A |s2cid=13606807 }}

{{citation |arxiv=1704.00373|title=The GAPS Programme with HARPS-N@TNG XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets|year=2017|doi=10.1051/0004-6361/201629882|last1=Bonomo|first1=A. S.|last2=Desidera|first2=S.|last3=Benatti|first3=S.|last4=Borsa|first4=F.|last5=Crespi|first5=S.|last6=Damasso|first6=M.|last7=Lanza|first7=A. F.|last8=Sozzetti|first8=A.|last9=Lodato|first9=G.|last10=Marzari|first10=F.|last11=Boccato|first11=C.|last12=Claudi|first12=R. U.|last13=Cosentino|first13=R.|last14=Covino|first14=E.|last15=Gratton|first15=R.|last16=Maggio|first16=A.|last17=Micela|first17=G.|last18=Molinari|first18=E.|last19=Pagano|first19=I.|last20=Piotto|first20=G.|last21=Poretti|first21=E.|last22=Smareglia|first22=R.|last23=Affer|first23=L.|last24=Biazzo|first24=K.|last25=Bignamini|first25=A.|last26=Esposito|first26=M.|last27=Giacobbe|first27=P.|last28=Hébrard|first28=G.|last29=Malavolta|first29=L.|last30=Maldonado|first30=J.|journal=Astronomy & Astrophysics|volume=A107|page=602|bibcode=2017A&A...602A.107B|s2cid=118923163|display-authors=29}}

{{Cite constellation|WASP-84}}

{{citation |arxiv=1912.00255 |doi=10.3847/1538-3881/ab4f79 |title=Do Metal-rich Stars Make Metal-rich Planets? New Insights on Giant Planet Formation from Host Star Abundances |year=2019 |last1=Teske |first1=Johanna K. |last2=Thorngren |first2=Daniel |last3=Fortney |first3=Jonathan J. |last4=Hinkel |first4=Natalie |last5=Brewer |first5=John M. |journal=The Astronomical Journal |volume=158 |issue=6 |page=239 |bibcode=2019AJ....158..239T |s2cid=208527082 |doi-access=free }}

{{cite journal |last1=Maciejewski |first1=G. |last2=Golonka |first2=J. |display-authors=etal |date=May 2023 |title=A hot super-Earth planet in the WASP-84 planetary system |journal=Monthly Notices of the Royal Astronomical Society |volume=525 |issue=1 |pages=L43–L49 |doi=10.1093/mnrasl/slad078 |doi-access=free |arxiv=2305.09177 |bibcode=2023MNRAS.525L..43M}}

}}

{{Sky|08|44|25.7033|+|01|51|36.1066}}

{{Stars of Hydra}}

Category:Hydra (constellation)

Category:Planetary transit variables

Category:G-type main-sequence stars

Category:Planetary systems with two confirmed planets

J08442570+0151361

BD+02 2056