WASP-8#Planetary system

{{Starbox image

| image = 250px

| caption = Artist's impression of a star like WASP-8

}}

{{Starbox observe

| epoch = J2000

| constell = Sculptor

| ra = {{RA|23|59|36.07119}}

| dec = {{DEC|−35|01|52.9236}}

| appmag_v = 9.87

}}

{{Starbox character

| type = main-sequence

| component1 = WASP-8A

| class = G8V

| b-v =

| u-b =

| variable =

| component2 = WASP-8B

| class2 = M

}}

{{Starbox astrometry

| radial_v = {{val|-1.38|0.26}}

| prop_mo_ra = 109.752

| prop_mo_dec = 7.615

| pm_footnote =

| parallax = 11.1052

| p_error = 0.0175

| parallax_footnote =

| absmag_v =

}}

{{Starbox relpos

| reference =

| epoch = 2016

| primary = WASP-8A

| component = WASP-8B

| angdistsec = {{val|4.520|0.005}}

| posang = {{val|170.9|0.1}}

| projsep = 408

}}

{{Starbox detail

| source =

| component1 = WASP-8A

| mass = {{val|1.093|0.024}}

| radius = {{val|0.976|0.020}}

| luminosity = 0.79

| gravity = {{val|4.498|0.018}}

| temperature = {{val|5600|80}}

| metal_fe = {{val|0.29|0.03}}

| rotational_velocity = {{val|1.90|0.05}}

| age_gyr = {{val|0.3|0.9|0.1}}

| component2 = WASP-8B

| mass2 = {{val|0.53|0.02}}

| temperature2 = {{val|3758|47|43}}

}}

{{Starbox catalog

| names = {{odlist | 2MASS = J23593607-3501530 | CD = -35 16019 | CPD = -35 9465 | PPM = 304426 | SAO = 214901 | TIC = 183532609 | TOI = 191 | TYC = 7522-505-1 | WASP = 8 | WDS = J23596-3502A}}

}}

{{Starbox reference

| Simbad = WASP-8 |sn=A

| Simbad2 = CD-35+16019B |sn2=B

| NSTED = WASP-8

}}

WASP-8 is a binary star system {{convert|294|ly|pc|lk=on|abbr=off}} away. The star system is much younger than the Sun at 300 million to 1.2 billion years age, and is heavily enriched in heavy elements, having nearly twice the concentration of iron compared to the Sun.

The primary, WASP-8A, is a magnitude 9.9 main-sequence yellow dwarf star. It is reported to be a G-type star with a temperature of 5600 K and has a mass 1.093{{±|0.024}}, a radius 0.976{{±|0.020}} and a luminosity of 0.79 times that of the Sun. There is a companion star WASP-8B located 4.5 arcseconds away with the same proper motion, indicating a stellar binary system. The binarity was confirmed in 2020. The axis orientation of the primary star is uncertain, but it is close to pointing one of the poles to the Earth.

Planetary system

The primary star is orbited by two known exoplanets, designated WASP-8b and WASP-8c. WASP-8b was discovered in 2010 by the astronomical transit method and was catalogued as part of the SuperWASP mission. WASP-8c was discovered in late 2013 with the radial velocity method.

{{OrbitboxPlanet begin

| table_ref =

}}

{{OrbitboxPlanet

| exoplanet = b

| mass = {{val|2.216|0.035}}

| period = {{val|8.158715|(16)}}

| semimajor = {{val|0.0817|0.0006}}

| eccentricity = {{val|0.3057|0.0046}}

| radius = {{val|1.165|0.032}}

| inclination = {{val|88.51|0.09}}

}}

{{OrbitboxPlanet

| exoplanet = c

| mass = {{val|9.45|2.26|1.04|p=≥}}

| period = {{val|4323|740|380}}

| semimajor = {{val|5.28|0.63|0.34}}

| eccentricity = 0

}}

References

{{reflist|refs=

{{cite journal | title=WASP-8b: a retrograde transiting planet in a multiple system | url=http://www.aanda.org/articles/aa/full_html/2010/09/aa14768-10/aa14768-10.html | last1=Queloz | first1=D. | last2=Anderson | first2=D. | last3=Collier Cameron | first3=A. | last4=Gillon | first4=M. | last5=Hebb | first5=L. | last6=Hellier | first6=C. | last7=Maxted | first7=P. | last8=Pepe | first8=F. | last9=Pollacco | first9=D. | last10=Ségransan | first10=D. | last11=Smalley | first11=B. | last12=Triaud | first12=A. H. M. J. | last13=Udry | first13=S. | last14=West | first14=R. | display-authors=1 | journal=Astronomy and Astrophysics | volume=517 | at=L1 | year=2010 | arxiv=1006.5089 | bibcode=2010A&A...517L...1Q | doi=10.1051/0004-6361/201014768 | s2cid=35774603 }}

{{citation|arxiv=1312.2954|year=2013|title=Friends of Hot Jupiters. I. A Radial Velocity Search for Massive, Long-Period Companions to Close-In Gas Giant Planets|doi=10.1088/0004-637X/785/2/126|last1=Knutson|first1=Heather A.|last2=Fulton|first2=Benjamin J.|last3=Montet|first3=Benjamin T.|last4=Kao|first4=Melodie|last5=Ngo|first5=Henry|last6=Howard|first6=Andrew W.|last7=Crepp|first7=Justin R.|last8=Hinkley|first8=Sasha|last9=Bakos|first9=Gaspar Á.|last10=Batygin|first10=Konstantin|last11=Johnson|first11=John Asher|last12=Morton|first12=Timothy D.|last13=Muirhead|first13=Philip S.|journal=The Astrophysical Journal|volume=785|issue=2|page=126|s2cid=42687848 |bibcode=2014ApJ...785..126K}}

{{cite journal |last1=Salz |first1=M. |last2=Schneider |first2=P. C. |display-authors=etal |date=April 2015 |title=High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood |journal=Astronomy & Astrophysics |volume=576 |issue= |pages=A42 |doi=10.1051/0004-6361/201425243 |arxiv=1502.00576 |bibcode=2015A&A...576A..42S}}

{{cite journal |last1=Bourrier |first1=V. |last2=Cegla |first2=H. M. |last3=Lovis |first3=C. |last4=Wyttenbach |first4=A. |display-authors=2 |date=March 2017 |title=Refined architecture of the WASP-8 system: A cautionary tale for traditional Rossiter-McLaughlin analysis |journal=Astronomy & Astrophysics |volume=599 |issue= |at=A33 |doi=10.1051/0004-6361/201629973 |doi-access=free |arxiv=1611.07985 |bibcode=2017A&A...599A..33B |s2cid=118864447}}

{{cite journal |last1=Bonomo |first1=A. S. |last2=Desidera |first2=S. |display-authors=etal |date=June 2017 |title=The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets |journal=Astronomy & Astrophysics |volume=602 |issue= |pages=A107 |doi=10.1051/0004-6361/201629882 |arxiv=1704.00373 |bibcode=2017A&A...602A.107B}}

{{citation|arxiv=2001.08224|year=2020|title=A multiplicity study of transiting exoplanet host stars|doi=10.1051/0004-6361/201937127|last1=Bohn|first1=A. J.|last2=Southworth|first2=J.|last3=Ginski|first3=C.|last4=Kenworthy|first4=M. A.|last5=Maxted|first5=P. F. L.|last6=Evans|first6=D. F.|journal=Astronomy & Astrophysics|volume=635|pages=A73|bibcode=2020A&A...635A..73B |s2cid=210861118}}

{{citation|arxiv=2001.08225|year=2020|title=A multiplicity study of transiting exoplanet host stars|doi=10.1051/0004-6361/201937334|last1=Southworth|first1=J.|last2=Bohn|first2=A. J.|last3=Kenworthy|first3=M. A.|last4=Ginski|first4=C.|last5=Mancini|first5=L.|journal=Astronomy & Astrophysics|volume=635|pages=A74|bibcode=2020A&A...635A..74S |s2cid=210860775}}

}}