arXiv subjects

Sharon Xuesong Wang

Publications and source records attributed to Sharon Xuesong Wang.

At least 19 recordsLinked to original sources

arXiv2026

Planets Around Solar Twins/Analogs (PASTA) III: Chemical Clock Relations in Planet-Hosting Solar Analogs

Context. Abundance ratios between elements synthesized on different nucleosynthetic timescales provide empirical chemical clocks for estimating stellar ages, but robust calibrations require homogeneous samples with precise stellar parameters and elemental abundances. Aims. We aim to investigate whether the presence of planets modifies empirical chemical clock relations. Methods. We present high-precision stellar parameters and elemental abundances for 52 new planet-hosting targets observed with Keck/HIRES, LBT/PEPSI, and Subaru/HDS. Combined with PASTA I and II, the full sample comprises 94 stars, of which 81 are identified as planet-hosting solar twins and analogs, and is used to characterize Galactic chemical evolution and derive empirical chemical clock relations. Results. We recover the expected Galactic chemical evolution trends, with $α$-elements such as Mg and S increasing with stellar age, while s-process elements such as Y, Ba, and Sr show negative age correlations. In contrast, Fe-peak elements and the r-process element Eu show little or no significant age dependence. These trends give rise to tight chemical clock relations based on [Y/Mg], [Y/Al], [Ba/Mg], [Ba/Al], and [Sr/Mg], with [Y/Mg] and [Y/Al] providing the strongest correlations. [Ba/Al] shows the steepest age dependence, and the Ba-based ratios are generally more sensitive to age than their Y-based counterparts. Conclusions. Planet-hosting solar analogs follow chemical-clock relations consistent with those of nearby solar twins, with no evidence for a significant planet-related effect. The derived relations are primarily applicable to local solar twins and analogs in the Galactic thin disk.

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arXiv2026

A Bayesian Search for Planet Engulfment Signatures in Solar Analogs

We present a systematic Bayesian search for chemical fingerprints of planet engulfment in 113 solar twins and analogs with high-precision abundance measurements, 45 of which host known or candidate planets or brown-dwarf companions. We constructed a Bayesian framework with three sets of abundance models: random scatter, Galactic chemical evolution, and planet engulfment with bulk Earth or CM chondrite compositions. Through model comparisons, we identified three candidates whose abundance patterns strongly favor planet engulfment over the alternatives, with inferred engulfed masses of about 7.5-33 Earth masses. Our findings correspond to a nominal detection rate of 1-3% for planet-engulfment signatures among solar analogs. This work extends abundance-based engulfment searches beyond the binary-star context and provides a framework for probing star-planet co-evolution with solar analogs, which goes beyond the commonly used abundance-condensation-temperature correlation (Tc slope).

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arXiv2026

JWST Exoplanetary Worlds and Elemental Survey (JEWELS) II: Condensation Temperature Trends and Galactic Chemical Evolution in JWST Planet-Hosting Stars

We present high-precision chemical abundances for 25 FGK-type stars hosting exoplanets observed in JWST Cycle 3 programs and all GTO and DDT programs from Cycles 1-3, based on high-resolution, high signal-to-noise ratio optical spectra from ground-based telescopes. Using a strictly differential, line-by-line analysis relative to the Sun, we derive homogeneous stellar parameters and abundances for 19 elements with atomic number Z <= 30. The sample spans a wide range of stellar properties, with [Fe/H] = -0.6 to +0.4 dex and effective temperatures between 4700 and 6600 K, and includes hosts of terrestrial and giant planets as well as multi-planet systems. We refine carbon and sulfur abundances in cool dwarfs using spectral synthesis, mitigating systematics from line blending. Several chemically interesting systems are identified, including mildly $α$-enhanced metal-poor stars and multi-planet hosts with elevated [C/O]. Using isochrone ages, we derive empirical Galactic chemical evolution (GCE) relations and examine condensation temperature (Tcond) trends before and after GCE correction. The $T_{cond}$ slopes show no dependence on stellar or planetary properties, indicating that they reflect a mixture of multiple mechanisms, with planet-related signatures entangled in GCE and stellar evolution effects. Thus, Tcond trends require careful interpretation. Several systems with significantly positive or negative Tcond slopes are identified. Together with forthcoming JWST atmospheric measurements, this homogeneous stellar abundance catalog provides a basis for probing star-planet chemical connections and planet formation pathways.

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arXiv2026

Six New Circumbinary Disk Occultation (CBO) Candidates from the Zwicky Transient Facility

Circumbinary disk occultation (CBO) systems, in which a misaligned circumbinary disk periodically obscures the central binary, provide unique probes of disk structure and dynamics. However, fewer than ten candidates with measured orbital periods were previously known. In this work, we identify six new CBO candidates, designated ZTF-CBO-1 through ZTF-CBO-6, through a systematic search of Zwicky Transient Facility (ZTF) photometry. These systems exhibit deep ($\gtrsim$1 mag) periodic dimming events with orbital periods ranging from $\sim$30 to $\sim$530 days and occultation durations spanning 32%-77% of their orbital periods. Such large duty cycles rule out the interpretation of circum-companion material occultation. Spectral energy distributions of ZTF-CBO-1 and ZTF-CBO-2 reveal infrared excess indicative of a dust component. TESS observations of ZTF-CBO-1 show no hours- to days-timescale variability during ingress and egress, indicating a smooth disk edge. These discoveries nearly double the known CBO sample, enabling meaningful population-level studies.

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arXiv2025

Planets Around Solar Twins/Analogs (PASTA) II: chemical abundances, systematic offsets, and clues to planet formation

Context. Previous studies have suggested that the Sun is relatively depleted in refractory elements compared to other solar twins or analogs, potentially as a result of planet formation. However, such conclusions are often limited by inhomogeneous samples and a lack of direct comparison with stars known to host planets. Aims. We aim to perform a homogeneous and precise abundance analysis of solar twins and analogs that host planets, to investigate possible chemical signatures associated with planet formation. Methods. We obtain high-resolution, high signal-to-noise ratio Magellan/MIKE spectra for 25 solar-like stars, including 22 confirmed or candidate planet hosts and three comparison stars. Stellar parameters and elemental abundances for 23 elements (from C to Eu) are derived through a strict line-by-line differential analysis relative to the Sun. Results. Our sample spans [Fe/H] = -0.23 to +0.18 dex and includes 20 solar analogs, six of which are solar twins. Typical abundance uncertainties range from 0.01 to 0.05 dex for lighter elements (e.g., Fe, Si, C, O, Na) and up to 0.1 dex for neutron-capture elements. The Sun is consistently depleted in refractory elements relative to all solar analogs and twins, regardless of planet type. Stars hosting small planets tentatively show slightly stronger refractory element depletion than those hosting giant planets, though the difference is not yet statistically significant. Conclusions. We emphasize the need for strictly differential, line-by-line analyses relative to the Sun, as well as careful consideration of systematic differences between instruments, to ensure consistency and the homogeneity required to achieve our goals.

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arXiv2025

Time-resolved p-mode oscillations for subgiant HD 142091 with NEID at WIYN

Detections of Earth-analog planets in radial velocity observations are limited by stellar astrophysical variability occurring on a variety of timescales. Current state-of-the-art methods to disentangle potential planet signals from intrinsic stellar signals assume that stellar signals introduce asymmetries to the line profiles that can therefore be separated from the pure translational Doppler shifts of planets. Here, we examine this assumption using a time series of resolved stellar p-mode oscillations in HD 142091 ($κ$ CrB), as observed on a single night with the NEID spectrograph at 2-minute cadence and with 25 cm/s precision. As an evolved subgiant star, this target has p-mode oscillations that are larger in amplitude (4-8 m/s) and occur on longer timescales (80 min.) than those of typical Sun-like stars of RV surveys, magnifying their corresponding effects on the stellar spectral profile. We show that for HD 142091, p-mode oscillations manifest primarily as pure Doppler shifts in the average line profile -- measured by the cross-correlation function (CCF) -- with "shape-driven" CCF variations as a higher-order effect. Specifically, we find that the amplitude of the shift varies across the CCF bisector, with 10% larger oscillation amplitudes closer to the core of the CCF, and 25% smaller oscillation amplitudes for bisector velocities derived near the wings; we attribute this trend to larger oscillation velocities higher in the stellar atmosphere. Using a line-by-line analysis, we verify that a similar trend is seen as a function of average line depth, with deeper lines showing larger oscillation amplitudes. Finally, we find no evidence that p-mode oscillations have a chromatic dependence across the NEID bandpass beyond that due to intrinsic line depth differences across the spectrum.

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arXiv2025

The Impact of Fiber Cross Contamination on Radial Velocity Precision

High-resolution spectrographs with precise radial velocity (PRV) capabilities require careful considerations in instrumental design and data processing in order to reach the 10 cm/s-level precision, which is needed for detecting Earth-like planets. In this work, we investigate the impact of fiber cross contamination on the RV precision via simulations, as modern PRV spectrographs often have multiple fiber traces on their spectral images. We simulated extracted 1-D spectra under the preliminary design of CHORUS, short for the Canary Hybrid Optical high-Resolution Ultra-stable Spectrograph, a dual-arm PRV spectrograph under construction for the Gran Telescopio de Canarias. We considered two types of fiber cross contaminations: contamination from calibration traces to neighboring science traces (or cal-sci contamination) and between science traces (or sci-sci contamination). We present results in four different scenarios: photon noise only, cal-sci contamination only, sci-sci contamination only, and all effects combined. For the preliminary design of CHORUS, we estimated that the cal-sci contamination fraction is smaller than 0.0001% in flux across the whole CCD for either arm, resulting in a negligible impact on the RV precision. Assuming worst-case scenarios, we estimated the sci-sci contamination to be up to 0.1% in some traces, corresponding to an additional RV error of up to 10 cm/s. We demonstrate the importance of considering fiber-trace spacing and cross contamination in PRV spectrographs, and we recommend careful design, operation, and spectral extraction algorithms to minimize and mitigate cross contamination to achieve the best possible instrumental RV precision.

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arXiv2025

TOI-6324b: An Earth-Mass Ultra-Short-Period Planet Transiting a Nearby M Dwarf

We report the confirmation of TOI-6324 b, an Earth-sized (1.059 $\pm$ 0.041 R$_\oplus$) ultra-short-period (USP) planet orbiting a nearby ($\sim$20 pc) M dwarf. Using the newly commissioned Keck Planet Finder (KPF) spectrograph, we have measured the mass of TOI-6324 b 1.17 $\pm$ 0.22 M$_\oplus$. Because of its extremely short orbit of just $\sim$6.7 hours, TOI-6324 b is intensely irradiated by its M dwarf host, and is expected to be stripped of any thick, H/He envelope. We were able to constrain its interior composition and found an iron core mass fraction (CMF = 27$\pm$37%) consistent with that of Earth ($\sim$33%) and other confirmed USPs. TOI-6324 b is the closest to Earth-sized USP confirmed to date. TOI-6324 b is a promising target for JWST phase curve and secondary eclipse observations (Emission Spectroscopy Metric = 25) which may reveal its surface mineralogy, day-night temperature contrast, and possible tidal deformation. From 7 sectors of TESS data, we report a tentative detection of the optical phase curve variation with an amplitude of 42$\pm$28 ppm.

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arXiv2025

Short-Period Small Planets with High Mutual Inclinations are more Common around Metal-Rich Stars

We present a correlation between the stellar metallicities and the mutual inclinations of multi-planet systems hosting short-period small planets (a/Rs<12, Rp<4Re). We analyzed 89 multi-planet systems discovered by Kepler, K2, and TESS, where the innermost planets have periods shorter than 10 days. We found that the mutual inclinations of the innermost two planets are higher and more diverse around metal-rich stars. The mutual inclinations are calculated as the absolute differences between the best-fit inclinations of the innermost two planets from transit modeling, which represent the lower limits of the true mutual inclinations. The mean and variance of the mutual inclination distribution of the metal-rich systems are 3.1+-0.5 and 3.1+-0.4 degrees, while for the metal-poor systems they are 1.3+-0.2 and 1.0+-0.2 degrees. This finding suggests that inner planetary systems around metal-rich stars are dynamically hotter. We summarized the theories that could plausibly explain this correlation, including the influence of giant planets, higher solid densities in protoplanetary disks around metal-rich stars, or secular chaos coupled with an excess of angular momentum deficits. Planet formation and population synthesis models tracking the mutual inclination evolution would be essential to fully understand this correlation.

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arXiv2024

C3PO III: On the Lithium Signatures Following Planet Engulfment by Stars

Planet engulfment has been identified as one of the mechanisms for enhancing lithium abundance in stars. However, comprehensive investigations into lithium signatures following such events remain limited. Stars born together, sharing a common origin and stellar characteristics, provide a unique opportunity to study these signatures and compare lithium abundances. We demonstrate that the distinctive signature of planet engulfment in lithium abundance is only discernible among highly similar stellar twins. We present lithium abundance measurements for 125 co-moving pairs of stars, representing the largest sample to date with a single, homogeneous assessment of high-precision lithium abundance. While lithium abundance enhancements in pairs showing planet engulfment signatures are within 0.35 dex, we find that even at fixed stellar parameters (temperature and age), the intrinsic scatter in lithium abundance is typically 0.35 dex for G/F dwarfs and can be as large as 0.6 dex for older and cooler stars due to internal stellar evolution processes. Since the planet engulfment signature from lithium can be masked by stellar intrinsic scatter, our findings raise questions about relying solely on lithium as an indicator for planet engulfment or attributing lithium-richness in stars primarily to planet engulfment events.

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arXiv2024

Planets Around Solar Twins/Analogs (PASTA) I.: High precision stellar chemical abundance for 17 planet-hosting stars and the condensation temperature trend

The Sun is depleted in refractory elements compared to nearby solar twins, which may be linked to the formation of giant or terrestrial planets. Here we present high-resolution, high signal-to-noise spectroscopic data for 17 solar-like stars hosting planets, obtained with Magellan II/MIKE, to investigate whether this depletion is related to planet formation. We derive stellar parameters, including stellar atmosphere, age, radius, mass, and chemical abundances for 22 elements from carbon to europium through line-by-line differential analysis. Our uncertainties range from 0.01 dex for Fe and Si to 0.08 dex for Sr, Y, and Eu. By comparing the solar abundances to those of the 17 stars, we investigate the differential abundance ([X/Fe]$_{\rm solar}$ - [X/Fe]$_{\rm star}$) versus condensation temperature ($T_c$) trend. In particular, we apply Galactic chemical evolution corrections to five solar twins within the full sample. Our results conform to previous studies that the Sun is relatively depleted in refractory compared to volatile elements. For both five solar twins and the rest of solar-like stars, we find that all stars hosting known gas giant planets exhibit negative $T_c$ trend slopes, suggesting that the Sun is relatively depleted in refractory elements compared to similar giant-planet-host stars. Additionally, we find no correlation between $T_c$ trend slopes and the total mass of detected terrestrial planets in each system, suggesting that terrestrial planet formation may not be the cause of refractory element depletion in the Sun.

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arXiv2024

Asteroseismology of the Nearby K-Dwarf $σ$ Draconis using the Keck Planet Finder and TESS

Asteroseismology of dwarf stars cooler than the Sun is very challenging due to the low amplitudes and rapid timescales of oscillations. Here, we present the asteroseismic detection of solar-like oscillations at 4-minute timescales ($ν_{\mathrm{max}}\sim4300μ$Hz) in the nearby K-dwarf $σ$ Draconis using extreme precision Doppler velocity observations from the Keck Planet Finder and 20-second cadence photometry from NASA's Transiting Exoplanet Survey Satellite. The star is the coolest dwarf star to date with both velocity and luminosity observations of solar-like oscillations, having amplitudes of $5.9\pm0.8\,$cm$\,\text{s}^{-1}$ and $0.8\pm0.2$ ppm, respectively. These measured values are in excellent agreement with established luminosity-velocity amplitude relations for oscillations and provide further evidence that mode amplitudes for stars with $T_{\mathrm{eff}}<\,5500\,$K diminish in scale following a $(L/M)^{1.5}$ relation. By modeling the star's oscillation frequencies from photometric data, we measure an asteroseismic age of $4.5\pm0.9\,\rm{(ran)} \pm 1.2\,\rm{(sys)}$ Gyr. The observations demonstrate the capability of next-generation spectrographs and precise space-based photometry to extend observational asteroseismology to nearby cool dwarfs, which are benchmarks for stellar astrophysics and prime targets for directly imaging planets using future space-based telescopes.

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arXiv2024

The Kinematic and Chemical Properties of the Close-in Planet Host Star 8 UMi

A recent study by Hon et al. reported that a close-in planet around the red clump star, 8 UMi, should have been engulfed during the expansion phase of its parent star's evolution. They explained the survival of this exoplanet through a binary-merger channel for 8 UMi. The key to testing this formation scenario is to derive the true age of this star: is it an old "imposter" resulting from a binary merger, or a genuinely young red clump giant? To accomplish this, we derive kinematic and chemical properties for 8 UMi using astrometric data from {\it Gaia} DR3 and the element-abundance pattern measured from a high-resolution ($R \sim 75,000$) spectrum taken by SOPHIE. Our analysis shows that 8 UMi is a normal thin-disk star with orbital rotation speed of $\it{V}_\mathrmϕ=\mathrm{244.96 km s^{-1}}$, and possesses a Solar metallicity ([Fe/H] $= -0.05 \pm 0.07$) and $α$-element abundance ratio ([$α$/Fe] $= +0.01 \pm 0.03$). By adopting well-established relationships between age and space velocities/elemental abundances, we estimate a kinematic age of $3.50^{+3.00}_{-2.00}$ Gyr, and a chemical age of $3.25^{+2.50}_{-1.50}$ Gyr from [C/N] and $3.47 \pm 1.96$ Gyr from [Y/Mg] for 8 UMi, respectively. These estimates are consistent with the isochrone-fitting age ($1.90^{+1.15}_{-0.30}$ Gyr) of 8 UMi, but are all much younger than the timescale required in a binary-merger scenario. This result challenges the binary-merger model; the existence of such a closely orbiting exoplanet around a giant star remains a mystery yet to be resolved.

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arXiv2024

A revisit of the Mass-Metallicity Trends in Transiting Exoplanets

The two prevailing planet formation scenarios, core-accretion and disk instability, predict distinct planetary mass-metallicity relations. Yet, the detection of this trend remains challenging due to inadequate data on planet atmosphere abundance and inhomogeneities in both planet and host stellar abundance measurements. Here we analyze high-resolution spectra for the host stars of 19 transiting exoplanets to derive the C, O, Na, S, and K abundances, including planetary types from cool mini-Neptunes to hot Jupiters ($T_{\rm eq}\ \sim$ 300 - 2700 K; planet radius $\sim$ 0.1 - 2 $R_{\rm J}$). Our Monte Carlo simulations suggest that the current dataset, updated based on Welbanks et al. 2019, is unable to distinguish between a linear relation and an independent distribution model for the abundance-mass correlation for water, Na, or K. To detect a trend with strong evidence (Bayes factor > 10) at the 2$σ$ confidence interval, we recommend a minimum sample of 58 planets with HST measurements of water abundances coupled with [O/H] of the host stars, or 45 planets at the JWST precision. Coupled with future JWST or ground-based high resolution data, this well-characterized sample of planets with precise host star abundances constitute an important ensemble of planets to further probe the abundance-mass correlation.

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arXiv2023

A Transiting Super-Earth in the Radius Valley and An Outer Planet Candidate Around HD 307842

We report the confirmation of a TESS-discovered transiting super-Earth planet orbiting a mid-G star, HD 307842 (TOI-784). The planet has a period of 2.8 days, and the radial velocity (RV) measurements constrain the mass to be 9.67+0.83/-0.82 [Earth Masses]. We also report the discovery of an additional planet candidate on an outer orbit that is most likely non-transiting. The possible periods of the planet candidate are approximately 20 to 63 days, with the corresponding RV semi-amplitudes expected to range from 3.2 to 5.4 m/s and minimum masses from 12.6 to 31.1 [Earth Masses]. The radius of the transiting planet (planet b) is 1.93+0.11/-0.09 [Earth Radii], which results in a mean density of 7.4+1.4/-1.2 g/cm^3 suggesting that TOI-784b is likely to be a rocky planet though it has a comparable radius to a sub-Neptune. We found TOI-784b is located at the lower edge of the so-called ``radius valley'' in the radius vs. insolation plane, which is consistent with the photoevaporation or core-powered mass loss prediction. The TESS data did not reveal any significant transit signal of the planet candidate, and our analysis shows that the orbital inclinations of planet b and the planet candidate are 88.60+0.84/-0.86 degrees and <= 88.3-89.2 degrees, respectively. More RV observations are needed to determine the period and mass of the second object, and search for additional planets in this system.

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arXiv2023

A search for stellar siblings of the ~ 200 Myr TOI-251b planetary system

Young planets (< 1 Gyr) are helpful for studying the physical processes occurring at the early stage of planet evolution. TOI-251 b is a recently discovered sub-Neptune orbiting a young G dwarf, which has an imprecise age estimation of 40-320 Myr. We select TOI-251 sibling candidates based on kinematics and spatial proximity to TOI-251, and further use the color-magnitude diagram (CMD) to refine the list and to compare to multiple open clusters. We report stellar rotational period for 321 sibling candidates in a 50 pc radius around TOI-251 by analyzing their stellar light curves, and find a color - rotational period sequence that lie in between the Group X (300 Myr) and Pleiades (120 Myr) members, suggesting an age ~ 200 Myr. A quantitative age analysis by using gyrochronology relations give 204 $\pm$ 45 Myr, consistent with the average Li-age of selected siblings (238 $\pm$ 38 Myr) and the Gaia variability age (193$^{102}_{-54}$ Myr). The detection fraction of comoving candidates that have short rotational period is 68.1%, much higher than the typical value in the field (14% - 16% from Kepler). The overdensity of young stars and consistency in age of stellar siblings suggest a potential young association candidate in the Pheonix-Grus constellation. Though TOI-251 b has a radius larger than most of its field-age counterparts, we are uncertain whether TOI-251 is inflated due to a lack of knowledge on the planet's mass.

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arXiv2023

Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions

Directly imaging temperate rocky planets orbiting nearby, Sun-like stars with a 6-m-class IR/O/UV space telescope, recently dubbed the Habitable Worlds Observatory, is a high priority goal of the Astro2020 Decadal Survey. To prepare for future direct imaging surveys, the list of potential targets should be thoroughly vetted to maximize efficiency and scientific yield. We present an analysis of archival radial velocity data for southern stars from the NASA/NSF Extreme Precision Radial Velocity Working Group's list of high priority target stars for future direct imaging missions (drawn from the HabEx, LUVOIR, and Starshade studies). For each star, we constrain the region of companion mass and period parameter space we are already sensitive to based on the observational baseline, sampling, and precision of the archival RV data. Additionally, for some of the targets we report new estimates of magnetic activity cycle periods, rotation periods, improved orbital parameters for previously known exoplanets, and new candidate planet signals that require further vetting or observations to confirm. Our results show that for many of these stars we are not yet sensitive to even Saturn-mass planets in the habitable zone, let alone smaller planets, highlighting the need for future EPRV vetting efforts before the launch of a direct imaging mission. We present evidence that the candidate temperate super-Earth exoplanet HD 85512 b is most likely due to the star's rotation, and report an RV acceleration for delta Pav which supports the existence of a distant giant planet previously inferred from astrometry.

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arXiv2022

Characterizing and Mitigating the Impact of Telluric Absorption in Precise Radial Velocities

Precise radial velocity (PRV) surveys are important for the search of Earth analogs around nearby bright stars. Such planets induce a small stellar reflex motion with RV amplitude of $\sim$10 cm/s. Detecting such a small RV signal poses important challenges to instrumentation, data analysis, and the precision of astrophysical models to mitigate stellar jitter. In this work, we investigate an important component in the PRV error budget - the spectral contamination from the Earth's atmosphere (tellurics). We characterize the effects of telluric absorption on the RV precision and quantify its contribution to the RV budget over time and across a wavelength range of 350 nm - 2.5$μ$m. We investigate the effectiveness in mitigating tellurics using simulated spectra of a solar twin star with telluric contamination over a year's worth of observations, and we extracted the RVs using two commonly adopted algorithms: dividing out a telluric model before performing cross-correlation or Forward Modeling the observed spectrum incorporating a telluric model. We assume various degrees of cleanness in removing the tellurics, including mimicking the lack of accurate knowledge of the telluric lines by using a mismatched line profile to model the "observed" tellurics. We conclude that the RV errors caused by telluric absorption can be suppressed to close to or even below the photon-limited precision in the optical region, especially in the blue, around 1-10 cm/s. At red through near-infrared wavelengths, however, the residuals of tellurics can induce an RV error on the m/s level even under the most favorable assumptions for telluric removal, leading to significant systematic noise in the RV time series and periodograms. If the red-optical or near-infrared becomes critical in the mitigation of stellar activity, systematic errors from tellurics can be eliminated with a space mission such as EarthFinder.

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