arXiv subjects

John H. Debes

Publications and source records attributed to John H. Debes.

At least 19 recordsLinked to original sources

arXiv2026

White dwarfs within 13 pc: insights from ultraviolet spectroscopy

We present a comprehensive multi-wavelength spectroscopic and photometric analysis of the 44 confirmed white dwarfs within 13 pc of the Sun. Combining flux-calibrated ultraviolet spectroscopy from the Hubble Space Telescope (STIS and COS) with ground-based optical spectroscopy, as well as photometry from Gaia, 2MASS, and WISE, we employ a combined fitting method to calculate atmospheric parameters. Each white dwarf is fitted with a bespoke model depending on its detailed atmospheric composition. Two strongly magnetic stars could not be fitted due to the complex splitting of their spectral lines. We find a systematic discrepancy in hydrogen-atmosphere white dwarfs with effective temperatures below 10,000K, where fits incorporating ultraviolet spectra result in effective temperatures that are 1 - 5 per cent higher than those derived from optical and infrared photometry alone. We re-classify three helium-atmosphere white dwarfs as metal enriched following a magnesium detection in their near-ultraviolet spectra: WD 0435-088, WD 1132-325 and WD 1917+386. In total, we identify five stars in the sample for which metals are only detected in the ultraviolet. Overall, we find that 30 per cent of the 13 pc white dwarfs show spectroscopic evidence of evolved planetary systems. Our analysis reveals no measurable difference between the hydrogen content of DQ and DC white dwarfs, although the upper limits of carbon in DCs are significantly below that of the DQ population. We find a multiplicity fraction of 33 per cent for the 13 pc white dwarfs.

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arXiv2025

JWST-TST High Contrast: Medium-resolution spectroscopy reveals a carbon-rich circumplanetary disk around the young accreting exoplanet Delorme 1 AB b

Young accreting planetary-mass objects are thought to draw material from a circumplanetary disk (CPD) composed of gas and dust. While the gas within the disk is expected to disperse within the first million years, strong accretion has nonetheless been detected in older systems, including the 30--45 Myr-old planetary-mass companion Delorme 1 AB b. We conducted spectroscopic observations with JWST/MIRI to investigate the presence of circumplanetary material around this young, accreting planet, and to characterize the planet's atmospheric properties and composition. We perform forward modeling using atmospheric models to characterize the planet's atmosphere. Beyond 10 microns, the SED becomes dominated by this CPD rather than the planet itself. We detect strong emission from HCN and C$_2$H$_2$, while no O-bearing species are observed in the CPD spectrum, suggesting the gas in the CPD has an elevated C/O. We also identify spatially extended H$_2$ emission around the planet, tracing warm gas, with indications that it may be at a higher temperature than the non-extended component. The mid-infrared spectrum of the planetary-mass companion Delorme 1 AB b reveals the first detection of bright C-bearing species in a CPD, together with an outflow traced by H$_2$ extended emission, that could be interpreted as a disk wind. The hot dust continuum emission suggests an inner cavity in the CPD. The presence of warm gas in the CPD provides constraints on the disk's chemical composition and physical conditions, opening up new avenues for disk studies. The study of these long-lived "Peter Pan" disks will enhance our understanding of how accretion persists in evolved low-mass systems, shedding light on their formation, longevity, and evolutionary pathways in planetary systems.

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arXiv2025

Hubble reveals complex multi-scale structure in the edge-on protoplanetary disk IRAS 23077+6707

We present high-resolution ($\lesssim 0.1''$) Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) imaging of the near edge-on ($i{\sim}80^\circ$) protoplanetary disk IRAS 23077+6707 ("Dracula's Chivito") obtained across six broadband filters spanning $0.4-1.6\,μ$m. These observations unveil the scattered light from this unusually large disk (${\sim}14''$, or ${\sim}4200\,\mathrm{au}$ at $300\,\mathrm{pc}$) in remarkable detail, revealing a rich tapestry of substructures, including brightness asymmetries and signatures of dynamical activity. Extended filaments are detected extending ${\sim}10''$ from the northern edges of both nebulae, while no comparable southern features are observed. In addition to large-scale asymmetries, the disk exhibits prominent wispy features that extend well above the midplane and are visible in all filters, suggesting a complex, possibly turbulent outer disk atmosphere shaped by infall, dynamical stirring, or gravitational instability. The central dark lane narrows from optical to near-IR wavelengths, and high-resolution millimeter data reveal compact midplane emission. Although our radiative transfer simulations show that the current data cannot yet distinguish between dust settling and no-settling scenarios, they underscore the need for resolved mid-infrared observations of this unique system. IRAS 23077+6707 thus represents a rare and valuable laboratory for studying the vertical structure, asymmetries, and evolutionary state of protoplanetary disks.

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arXiv2025

The MIRI Excesses around Degenerates (MEAD) Survey I: A candidate cold brown dwarf in orbit around the nearby white dwarf 2MASS J09424023-4637176

The MIRI Excesses Around Degenerates Survey is a Cycle 2 James Webb Space Telescope (JWST) Survey program designed to image nearby white dwarfs in the mid-IR with the MIRI imaging mode. Only a handful of white dwarfs have previously been observed beyond 8~\micron. This survey gathered observations for 56 white dwarfs within 25~pc at 10 and 15~\micron, probing each white dwarf for unresolved IR excesses, IR flux deficits indicative of collision induced absorption, or resolved substellar companions. We present in this paper observations of our first target, 2MASS J09424023-4637176, (also UCAC4 217-039132), henceforth called MEAD 62. It is a magnetic DA white dwarf with an estimated age of $7.6^{+1.7}_{-2.2}$\,Gyr. A red candidate companion, MEAD 62B, about 2 magnitudes fainter at 15\,$μ$m than the white dwarf is detected at an apparent separation of 1.95". If confirmed, MEAD 62B, would be a $0.014^{+0.002}_{-0.003}$\,\Msun\, brown dwarf with T$_{\rm eff} = 343^{+7}_{-11}$\,K, according to ATMO2020 evolutionary models. Although its red F1000W$-$F1500W color is similar to background galaxies, MEAD 62B, is consistent with being an unresolved point-source from empirical PSF fitting. A false positive analysis yields an expectation number of 0.66 red (F1000W$-$F1500$ \geq +0.80$\,mag) unresolved sources within the same separation (r$\leq2$ arcsec) for the entire MEAD survey. Thus, this candidate companion as likely to be an actual companion as a false-positive unresolved background galaxy. Additional observations to measure common proper motion or sample the SED are warranted to confirm the nature of MEAD 62B. A deep near-infrared imaging detection is achievable from the ground while JWST is needed at longer infrared wavelengths.

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arXiv2025

Composition of planetary debris around the white dwarf GD 362

White dwarf stars with high abundances of heavy elements in their atmospheres and infrared excesses are believed to be accreting planetary material. GD 362 is one of the most heavily polluted white dwarfs and has an exceptionally strong mid-infrared excess, reprocessing 2.4% of the star's light into the mid-infrared. We present a high signal-to-noise, medium-resolution spectrum of GD 362 obtained with JWST, covering 0.6 to 17 microns, along with photometry out to 25.5 microns. The mid-infrared spectrum is dominated by an exceptionally strong 9 to 11 micron silicate feature, which can be explained by a combination of olivine and pyroxene silicate minerals. Grains such as carbon, hotter than silicates, are required to explain the near-infrared emission. The silicates and carbon reside in a disk from 140 to 1400 stellar radii, and the disk scale height is greater than half the stellar radius. The elemental abundances of the solid material, relative to Si, are within a factor of 2 of meteoritic (CI chondrites) for C, O, Mg, Al, and Fe, with Al elevated and O slightly depleted. A similar pattern is observed for the abundances of accreted material in the stellar photosphere. Hydrogen is an exception, because no significant H-bearing minerals or water were detected in the disk, despite a large H abundance in the photosphere.

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arXiv2025

Metal Polluted White Dwarfs with 21 μm IR excesses from JWST/MIRI: Planets or Dust?

White dwarfs with metal pollution are caused by the accretion of rocky dust from tidally disrupted minor bodies and are signposts for planetary systems. These minor bodies are perturbed by planets that have survived post-main sequence evolution. Open questions exist as to the typical mass of the perturbers and the specific planetary architectures that cause metal pollution. JWST's sensitivity in the mid-IR has opened new doors to deciphering polluted white dwarfs. We present JWST Cycle 1 MIRI imaging of four nearby metal-polluted white dwarfs with the goal of detecting and characterizing planetary companions. With deep mid-IR imaging we are sensitive to cold Jupiter-mass planet analogs. In addition to finding two candidate planetary companions, for the first time we detect significant excesses above the expected photospheric emission at 21~$μ$m for two of our targets, WD 2149+021 and WD 2105-820. WD 2105-280 has a candidate planetary companion at a projected separation of 34 au and an infrared excess--if both candidates are confirmed, it would represent the first WD multi-planet system. We investigate whether these excesses could be caused by very low luminosity warm dust disks or planets. While both are likely, we argue that the most likely explanation for the excesses is that they are the thermal emission from jovian-mass planets in orbits with semi-major axes $<$10 au, using a combination of observational constraints. If most of the candidate planets presented here are confirmed, it would suggest that metal polluted white dwarfs are frequently orbited by at least one giant planet.

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arXiv2025

Review and prospects of hot exozodiacal dust research for future exo-Earth direct imaging missions

Hot exozodiacal dust is dust in the innermost regions of planetary systems, at temperatures around 1000K to 2000K, and commonly detected by near-infrared interferometry. The phenomenon is poorly understood and has received renewed attention as a potential risk to a planned future space mission to image potentially habitable exoplanets and characterize their atmospheres (exo-Earth imaging) such as the Habitable Worlds Observatory (HWO). In this article, we review the current understanding of hot exozodiacal dust and its implications for HWO. We argue that the observational evidence suggests that the phenomenon is most likely real and indeed caused by hot dust, although conclusive proof in particular of the latter statement is still missing. Furthermore, we find that there exists as of yet no single model that is able to successfully explain the presence of the dust. We find that it is plausible and not unlikely that large amounts of hot exozodiacal dust in a system will critically limit the sensitivity of exo-Earth imaging observations around that star. It is thus crucial to better understood the phenomenon in order to be able to evaluate the actual impact on such a mission, and current and near-future observational opportunities for acquiring the required data exist. At the same time, hot exozodiacal dust (and warm exozodiacal dust closer to a system's habitable zone) has the potential to provide important context for HWO observations of rocky, HZ planets, constraining the environment in which these planets exist and hence to determine why a detected planet may be capable to sustain life or not.

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arXiv2024

New Ultracool Companions to Nearby White Dwarfs

We conducted a search for new ultracool companions to nearby white dwarfs using multiple methods, including the analysis of colors and examination of images in both the optical and the infrared. Through this process, we identified fifty-one previously unrecognized systems with candidate ultracool companions. Thirty-one of these systems are resolved in at least one catalog, and all but six are confirmed as co-moving companions via common proper motion and consistent parallax measurements (when available). We have followed up four co-moving companions with near-infrared spectroscopy and confirm their ultracool nature. The remaining twenty candidates are unresolved, but show clear signs of infrared excess which is most likely due to the presence of a cold, low-mass companion or a dusty circumstellar disk. Three of these unresolved systems have existing optical spectra that clearly show the presence of a cool stellar companion to the white dwarf primary via spectral decomposition. These new discoveries, along with our age estimates for the primary white dwarfs, will serve as valuable benchmark systems for future characterization of ultracool dwarfs.

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arXiv2024

Deepest limits on scattered light emission from the Epsilon Eridani inner debris disk with HST/STIS

Epsilon Eridani ($ε$ Eri) is one of the first debris disk systems detected by the Infrared Astronomical Satellite (IRAS). However, the system has thus far eluded detection in scattered light with no components having been directly imaged. Its similarity to a relatively young Solar System combined with its proximity makes it an excellent candidate to further our understanding of planetary system evolution. We present a set of coronagraphic images taken using the Space Telescope Imaging Spectrograph (STIS) coronagraph on the Hubble space telescope at a small inner working angle to detect a predicted warm inner debris disk inside 1". We used three different post-processing approaches; Non-negative Matrix Factorization (NMF), Karhunen-Lo`eve Image Processing (KLIP), and Classical reference differential imaging (RDI), to best optimize reference star subtraction, and find that NMF performed the best overall while KLIP produced the absolute best contrast inside 1". We present limits on scattered light from warm dust, with constraints on surface brightness at 6 mJy/as$^2$ at our inner working angle of 0.6". We also place a constraint of 0.5 mJy/as$^2$ outside 1", which gives us an upper limit on the brightness for outer disks and substellar companions. Finally, we calculated an upper limit on the dust albedo at $ω<$ 0.487.

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arXiv2024

3C 273 Host Galaxy with Hubble Space Telescope Coronagraphy

The close-in regions of bright quasars' host galaxies have been difficult to image due to the overwhelming light from the quasars. With coronagraphic observations in visible light using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, we removed 3C 273 quasar light using color-matching reference stars. The observations revealed the host galaxy from 60" to 0.2" with nearly full angular coverage. Isophote modeling revealed a new core jet, a core blob, and multiple smaller-scale blobs within 2.5". The blobs could potentially be satellite galaxies or infalling materials towards the central quasar. Using archival STIS data, we constrained the apparent motion of its large scale jets over a 22 yr timeline. By resolving the 3C 273 host galaxy with STIS, our study validates the coronagraph usage on extragalactic sources in obtaining new insights into the central ~kpc regions of quasar hosts.

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arXiv2023

A Companion in V1247 Ori Supported by Spiral Arm Pattern Motion

While there have been nearly two dozen of spiral arms detected from planet-forming disks in near-infrared scattered light, none of their substellar drivers have been confirmed. By observing spiral systems in at least two epochs spanning multiple years, and measuring the motion of the spirals, we can distinguish the cause of the spirals, and locate the orbits of the driving planets if they trigger the spirals. Upon a recent validation of this approach using the co-motion between a stellar companion and a spiral, we obtained a second epoch observation for the spiral system in the disk of V1247 Ori in the $H$-band polarized scattered light using VLT/SPHERE/IRDIS. Combining our observations with archival IRDIS data, we established a $4.8$ yr timeline to constrain the V1247 Ori spiral motion. We obtained a pattern speed of $0.40^{\circ} \pm 0.09^{\circ}$ yr$^{-1}$ for the north-east spiral. This corresponds to an orbital period of $900\pm200$ yr, and thus the semi-major axis of the hidden planetary driver is $118\pm19$ au for a 2.0 $\pm$ 0.1 M$_\odot$ central star. The location agrees with the gap in ALMA dust continuum observations, providing joint support for the existence of a companion driving the scattered-light spirals while carving a millimeter gap. With an angular separation of 0.29" $\pm$ 0.05", this hidden companion is an ideal target for JWST imaging.

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arXiv2023

A Uniform Analysis of Debris Disks with the Gemini Planet Imager I: An Empirical Search for Perturbations from Planetary Companions in Polarized Light Images

The Gemini Planet Imager (GPI) has excelled in imaging debris disks in the near-infrared. The GPI Exoplanet Survey (GPIES) imaged twenty-four debris disks in polarized $H$-band light, while other programs observed half of these disks in polarized $J$- and/or $K1$-bands. Using these data, we present a uniform analysis of the morphology of each disk to find asymmetries suggestive of perturbations, particularly those due to planet-disk interactions. The multi-wavelength surface brightness, the disk color and geometry permit identification of any asymmetries such as warps or disk offsets from the central star. We find that nineteen of the disks in this sample exhibit asymmetries in surface brightness, disk color, disk geometry, or a combination of the three, suggesting that for this sample, perturbations, as seen in scattered light, are common. The relationship between these perturbations and potential planets in the system are discussed. We also explore correlations among stellar temperatures, ages, disk properties, and observed perturbations. We find significant trends between the vertical aspect ratio and the stellar temperature, disk radial extent, and the dust grain size distribution power-law, $q$. We also confirm a trend between the disk color and stellar effective temperature, where the disk becomes increasingly red/neutral with increasing temperature. Such results have important implications on the evolution of debris disk systems around stars of various spectral types.

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arXiv2023

Debris Disk Color with the Hubble Space Telescope

Multi-wavelength scattered light imaging of debris disks may inform dust properties including typical size and mineral composition. Existing studies have investigated a small set of individual systems across a variety of imaging instruments and filters, calling for uniform comparison studies to systematically investigate dust properties. We obtain the surface brightness of dust particles in debris disks by post-processing coronagraphic imaging observations, and compare the multi-wavelength reflectance of dust. For a sample of resolved debris disks, we perform a systematic analysis on the reflectance properties of their birth rings. We reduced the visible and near-infrared images of 23 debris disk systems hosted by A through M stars using two coronagraphs onboard the Hubble Space Telescope: the STIS instrument observations centering at 0.58 $μ$m, and the NICMOS instrument at 1.12 $μ$m or 1.60 $μ$m. For proper recovery of debris disks, we used classical reference differential imaging for STIS, and adopted non-negative matrix factorization with forward modeling for NICMOS. By dividing disk signals by stellar signals to take into account of intrinsic stellar color effects, we systematically obtained and compared the reflectance of debris birth rings at ~90 deg scattering angle. Debris birth rings typically exhibit a blue color at ~90 deg scattering angle. As the stellar luminosity increases, the color tends to be more neutral. A likely L-shaped color-albedo distribution indicates a clustering of scatterer properties. The observed color trend correlates with the expected blow-out size of dust particles. The color-albedo clustering likely suggests different populations of dust in these systems. More detailed radiative transfer models with realistic dust morphology will contribute to explaining the observed color and color-albedo distribution of debris systems.

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arXiv2023

Discovery of a resolved white dwarf-brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB

We present the confirmation of SDSS J222551.65+001637.7AB as a closely separated, resolved, white dwarf-brown dwarf binary. We have obtained spectroscopy from GNIRS and seeing-limited $K_s$-band imaging from NIRI on Gemini North. The target is spatially resolved into its constituent components: a 10926$ \pm$ 246 K white dwarf, with log $g = 8.214 \pm 0.168$ and a mass of 0.66$^{+0.11}_{-0.06}$ M$_{\odot}$, and an L4 brown dwarf companion, which are separated by $0.9498 \pm 0.0022$". We derive the fundamental properties of the companion from the Sonora-Bobcat evolutionary models, finding a mass of $25-53$ M$_{\text{Jup}}$ and a radius of $0.101-0.128$ R$_{\odot}$ for the brown dwarf, at a confidence level of 1$σ$. We use wdwarfdate to determine the age of the binary as $1.97^{+4.41}_{-0.76}$ Gyr. A kinematic analysis shows that this binary is likely a member of the thick disc. The distance to the binary is 218$^{+14}_{-13}$ pc, and hence the projected separation of the binary is 207$^{+13}_{-12}$ AU. Whilst the white dwarf progenitor was on the main sequence the binary separation would have been $69 \pm 5$ AU. SDSS J222551.65+001637.7AB is the third closest spatially resolved white dwarf-brown dwarf binary after GD 165AB and PHL 5038AB.

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arXiv2022

Disks in Nearby Young Stellar Associations Found Via Virtual Reality

The Disk Detective citizen science project recently released a new catalog of disk candidates found by visual inspection of images from NASA's Wide-Field Infrared Survey Explorer (WISE) mission and other surveys. We applied this new catalog of well-vetted disk candidates to search for new members of nearby young stellar associations (YSAs) using a novel technique based on Gaia data and virtual reality (VR). We examined AB Doradus, Argus, $β$ Pictoris, Carina, Columba, Octans-Near, Tucana-Horologium, and TW Hya by displaying them in VR together with other nearby stars, color-coded to show infrared excesses found via Disk Detective. Using this method allows us to find new association members in mass regimes where isochrones are degenerate. We propose ten new YSA members with infrared excesses: three of AB Doradus (HD 44775, HD 40540 and HD 44510), one of $β$ Pictoris (HD 198472), two of Octans-Near (HD 157165 and BD+35 2953), and four disk-hosting members of a combined population of Carina, Columba and Tucana-Horologium: CPD-57 937, HD 274311, HD 41992, and WISEA J092521.90-673224.8. This last object (J0925) appears to be an extreme debris disk with a fractional infrared luminosity of $3.7 \times 10^{-2}$. We also propose two new members of AB Doradus that do not show infrared excesses: TYC 6518-1857-1 and CPD-25 1292. We find HD 15115 appears to be a member of Tucana-Horologium rather than $β$ Pictoris. We advocate for membership in Columba-Carina of HD 30447, CPD-35 525, and HD 35841. Finally, we propose that three M dwarfs, previously considered members of Tuc-Hor are better considered a separate association, tentatively called ``Smethells 165''.

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arXiv2021

A Wide Planetary Mass Companion Discovered Through the Citizen Science Project Backyard Worlds: Planet 9

Through the Backyard Worlds: Planet 9 citizen science project we discovered a late-type L dwarf co-moving with the young K0 star BD+60 1417 at a projected separation of 37" or 1662 AU. The secondary - CWISER J124332.12+600126.2 (W1243) - is detected in both the CatWISE2020 and 2MASS reject tables. The photometric distance and CatWISE proper motion both match that of the primary within ~1sigma and our estimates for chance alignment yield a zero probability. Follow-up near infrared spectroscopy reveals W1243 to be a very red 2MASS color(J-Ks=2.72), low-surface gravity source that we classify as L6 - L8gamma. Its spectral morphology strongly resembles that of confirmed late-type L dwarfs in 10 - 150 Myr moving groups as well as that of planetary mass companions. The position on near- and mid-infrared color-magnitude diagrams indicates the source is redder and fainter than the field sequence, a telltale sign of an object with thick clouds and a complex atmosphere. For the primary we obtained new optical spectroscopy and analyzed all available literature information for youth indicators. We conclude that the Li I abundance, its loci on color-magnitude and color-color diagrams, and the rotation rate revealed in multiple TESS sectors are all consistent with an age of 50 - 150 Myr. Using our re-evaluated age of the primary, the Gaia parallax along with the photometry and spectrum for W1243 we find a Teff=1303+/-31 K, logg=4.3+/-0.17 cm s-2, and a mass of 15+/-5 MJup. We find a physical separation of ~1662 AU and a mass ratio of ~0.01 for this system. Placing it in context with the diverse collection of binary stars, brown dwarf and planetary companions, the BD+60 1417 system falls in a sparsely sampled area where the formation pathway is difficult to assess.

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arXiv2021

Velocity-imaging the rapidly precessing planetary disc around the white dwarf HE 1349-2305 using Doppler tomography

The presence of planetary material in white dwarf atmospheres, thought to be accreted from a dusty debris disc produced via the tidal disruption of a planetesimal, is common. Approximately five per cent of these discs host a co-orbital gaseous component detectable via emission from atomic transitions - usually the 8600 Angstrom CaII triplet. These emission profiles can be highly variable in both morphology and strength. Furthermore, the morphological variations in a few systems have been shown to be periodic, likely produced by an apsidally precessing asymmetric disc. Of the known gaseous debris discs, that around HE1349-2305 has the most rapidly evolving emission line morphology, and we present updated spectroscopy of the CaII triplet of this system. The additional observations show that the emission line morphologies vary periodically and consistently, and we constrain the period to two aliases of 459$\pm$3d and 502$\pm$3d. We produce images of the CaII triplet emission from the disc in velocity space using Doppler tomography - only the second such imaging of a white dwarf debris disc. We suggest that the asymmetric nature of these velocity images is generated by gas moving on eccentric orbits with radially-dependent excitation conditions via photo-ionisation from the white dwarf. We also obtained short-cadence (~ 4 min) spectroscopy to search for variability on the time-scale of the disc's orbital period (~ hours) due to the presence of a planetesimal, and rule out variability at a level of ~ 1.4 per cent.

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arXiv2021

Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project

Through the Backyard Worlds: Planet 9 citizen science project, we have identified a wide-separation ($\sim$10', $\sim$9900 au projected) substellar companion to the nearby ($\sim$17.5 pc), mid-M dwarf Ross 19. We have developed a new formalism for determining chance alignment probabilities based on the BANYAN $Σ$ tool, and find a 100% probability that this is a physically associated pair. Through a detailed examination of Ross 19A, we find that the system is metal-poor ([Fe/H]=$-$0.40$\pm$0.12) with an age of 7.2$^{+3.8}_{-3.6}$ Gyr. Combining new and existing photometry and astrometry, we find that Ross 19B is one of the coldest known wide-separation companions, with a spectral type on the T/Y boundary, an effective temperature of 500$^{+115}_{-100}$ K, and a mass in the range 15-40 $M_{\rm Jup}$. This new, extremely cold benchmark companion is a compelling target for detailed characterization with future spectroscopic observations using facilities such as the Hubble Space Telescope or James Webb Space Telescope.

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