J/AJ/162/296ivo://CDS.VizieR/J/AJ/162/296doi:10.26093/cds/vizier.51620296CDSXu S.Diamond-lowe H.Macdonald R.J.Vanderburg A.Blouin S.,Dufour P.Gao P.Kreidberg L.Leggett S.K.Mann A.W.Morley C.V.,Stephens A.W.O'connor C.E.Thao P.C.Lewis N.K.2022-06-13T13:35:03Z2022-03-28T07:08:04ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frexoplanetswhite-dwarf-starsvisible-astronomyspectroscopyinfrared-astronomyWD1856+534b is a Jupiter-sized, cool giant planet candidate transiting the white dwarf WD1856+534. Here, we report an optical transmission spectrum of WD1856+534b obtained from ten transits using the Gemini Multi-Object Spectrograph. This system is challenging to observe due to the faintness of the host star and the short transit duration. Nevertheless, our phase-folded white light curve reached a precision of 0.12%. WD1856+534b provides a unique transit configuration compared to other known exoplanets: the planet is 8x larger than its star and occults over half of the stellar disk during mid-transit. Consequently, many standard modeling assumptions do not hold. We introduce the concept of a "limb darkening corrected, time-averaged transmission spectrum" and propose that this is more suitable than (R_p,{lambda}_/R_s_)^2^ for comparisons to atmospheric models for planets with grazing transits. We also present a modified radiative transfer prescription. Though the transmission spectrum shows no prominent absorption features, it is sufficiently precise to constrain the mass of WD1856+534b to be >0.84M_J_ (to 2{sigma} confidence), assuming a clear atmosphere and a Jovian composition. High-altitude cloud decks can allow lower masses. WD1856+534b could have formed either as a result of common envelope evolution or migration under the Kozai-Lidov mechanism. Further studies of WD1856+534b, alongside new dedicated searches for substellar objects around white dwarfs, will shed further light on the mysteries of post-main-sequence planetary systems.2021AJ....162..296Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/296CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)J/MNRAS/413/1121 : SDSS post-common envelope bin. X (Rebassa-Mansergas+ 2011)J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)J/MNRAS/426/739 : Velocities for seven transiting hot Jupiters (Hellier+, 2012)J/ApJ/766/3 : Limb-darkening coefficients eclipsing WD* (Gianninas+, 2013)J/A+A/605/A95 : CH4 & hot methane continuum hybrid line list (Yurchenko+, 2017)J/AJ/156/18 : APOGEE DR14:Binary comp. of evolved stars (Price-Whelan+, 2018)J/ApJ/878/63 : Cool WD atmos. models. IV. Spectral evolution (Blouin+, 2019)J/MNRAS/490/4638 : ExoMol molecular line lists. XXXV. NH3 (Coles+, 2019)J/other/Nat/576.61 : WDJ0914+1914 X-Shooter spectrum (Gansicke+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/162/296https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/162/296http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/162/296https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/162/296https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/162/296http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/162/296GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/AJ/162/296/table5Derived transmission spectrum of WD1856+534brecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdamin[0.52/0.99] Lower wavelength rangeumem.wl;stat.minfloatlambdamax[0.54/1.1] Upper wavelength rangeumem.wl;stat.maxfloatq1[0.09/0.24] q1 quadratic limb darkening parameterphot.limbDarkfloate_q1[0.07/0.2] Uncertainty in q1stat.errorfloatq2[0.04/0.18] q2 quadratic limb darkening parameterphot.limbDarkfloate_q2[0.08/0.3] Uncertainty in q2stat.errorfloatRp/R*[7.85/7.87] Planet to stellar radii ratiophys.size;arith.ratiofloate_Rp/R*[0.001/0.004] Uncertainty in Rp/R*stat.errorfloatsigma[0.32/0.34] Limb darkening corrected time-averaged transit depthphot.limbDarkfloate_sigma[0.0006/0.002] Uncertainty in sigmastat.errorfloatFlag[e] Data excluded from atmosphere fitting (1)meta.code.errorchar