arXiv subjects

Andrew Vanderburg

Publications and source records attributed to Andrew Vanderburg.

At least 55 records · Page 3Linked to original sources

arXiv2025

Sensitivity to Sub-Io-sized Exosatellite Transits in the MIRI LRS Lightcurve of the Nearest Substellar Worlds

JWST's unprecedented sensitivity enables precise spectrophotometric monitoring of substellar worlds, revealing atmospheric variability driven by mechanisms operating across different pressure levels. This same precision now permits exceptionally sensitive searches for transiting exosatellites, small terrestrial companions to these worlds. Using a novel simultaneous dual-band search method to address host variability, we present a search for transiting exosatellites in an 8-hour JWST/MIRI LRS lightcurve of the nearby ($2.0\,pc$) substellar binary WISE J1049-5319AB, composed of two $\sim30 M_{\rm Jup}$ brown dwarfs separated by $3.5\,au$ and viewed near edge-on. Although we detect no statistically significant transits, our injection-recovery tests demonstrate sensitivity to satellites as small as $0.275\,R_{\oplus}$ ($0.96\,R_{\rm Io}$ or $\sim$1 lunar radius), corresponding to 300ppm transit depths, and satellite-to-host mass ratios $>$$10^{-6}$. This approach paves the way for detecting Galilean-moon analogs around directly imaged brown dwarfs, free-floating planets, and wide-orbit exoplanets, dozens of which are already scheduled for JWST lightcurve monitoring. In our Solar System, each giant planet hosts on average 3.5 moons above this threshold, suggesting that JWST now probes a regime where such companions are expected to be abundant. The technique and sensitivities demonstrated here mark a critical step toward detecting exosatellites and ultimately enabling constraints on the occurrence rates of small terrestrial worlds orbiting $1\text{-}70$$M_{\rm Jup}$ hosts.

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arXiv2025

The Fate of Oceans on First-Generation Planets Orbiting White Dwarfs

Several groups have recently suggested that small planets orbiting very closely around white dwarf stars could be promising locations for life to arise, even after stellar death. There are still many uncertainties, however, regarding the existence and habitability of these worlds. Here, we consider the retention of water during post-main-sequence evolution of a Sun-like star, and during the subsequent migration of planets to the white dwarf's habitable zone. This inward migration is driven by dynamical mechanisms such as planet-planet interactions in packed systems, which can excite planets to high eccentricities, setting the initial conditions for tidal migration into short-period orbits. In order for water to persist on the surfaces of planets orbiting white dwarfs, the water must first survive the AGB phase of stellar evolution, then avoid being lost due to photoevaporation due to X-ray and extreme ultraviolet (XUV) radiation from the newly-formed white dwarf, and then finally survive the tidal migration of the planet inwards to the habitable zone. We find that while this journey will likely desiccate large swaths of post-main-sequence planetary systems, planets with substantial reservoirs of water may retain some surface water, especially if their migration occurs at later white dwarf cooling ages. Therefore, although stellar evolution may pose a challenge for the retention of water on exoplanet surfaces, it is possible for planets to retain surface oceans even as their host stars die and their orbits evolve.

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arXiv2025

NGTS-11 c: a transiting Neptune-mass planet interior to the warm Saturn NGTS-11 b

We report the discovery of NGTS-11 c, a transiting warm Neptune ($P \approx 12.8$ d; $M_{p} = 1.2^{+0.3}_{-0.2} M_{\mathrm{Nep}}$; $R_{p} = 1.24 \pm 0.03 R_{\mathrm{Nep}}$), in an orbit interior to the previously reported transiting warm Saturn NGTS-11 b ($P \approx 35.5$ d). We also find evidence of a third outer companion orbiting the K-dwarf NGTS-11. We first detected transits of NGTS-11 c in TESS light curves and confirmed them with follow-up transits from NGTS and many other ground-based facilities. Radial-velocity monitoring with the HARPS and FEROS spectrographs revealed the mass of NGTS-11 c and provides evidence for a long-period companion ($P > 2300$ d; $M_{p} \sin i > 3.6 M_{\mathrm{Jup}}$). Taking into account the two additional bodies in our expanded datasets, we find that the mass of NGTS-11 b ($M_{p} = 0.63 \pm 0.09 M_{\mathrm{Sat}}$; $R_{p} = 0.97 \pm 0.02 R_{\mathrm{Sat}}$) is lower than previously reported ($M_{p} = 1.2 \pm 0.3 M_{\mathrm{Sat}}$). Given their near-circular and compact orbits, NGTS-11 c and b are unlikely to have reached their present locations via high-eccentricity migration. Instead, they probably either formed in situ or formed farther out and then underwent disk migration. A comparison of NGTS-11 with the eight other known systems hosting multiple well-characterized warm giants shows that it is most similar to Kepler-56. Finally, we find that the commonly used 10-day boundary between hot and warm Jupiters is empirically well supported.

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arXiv2025

Metallicities from High-Resolution TRES Spectra with uberMS: Performance Benchmarks and Literature Comparison

As the field of exoplanetary astronomy has matured, demand has grown for precise stellar abundances to probe subtle correlations between stellar compositions and planetary demographics. However, drawing population-level conclusions from the disparate measurements in the literature is challenging, with various groups measuring metallicities using bespoke codes with differing line lists, radiative transfer models, and other assumptions. Homogeneous analyses are thus critical. Here we use the neural-net framework uberMS to measure iron abundances and alpha enrichments from high-resolution optical spectra observed by the Tillinghast Reflector Echelle Spectrograph (TRES), a key resource used for the follow-up of candidate exoplanet hosts. To contextualize these measurements and benchmark our method's performance, we compare to external constraints on metallicity using the Hyades cluster, wide binaries, and asteroids, to external constraints on $T_{\rm eff}$ and $\log g$ using stars with interferometric radii, and to the results of other abundance measurement methods using overlap samples with the APOGEE and SPOCS catalogs, as well as by applying the SPC method directly to TRES spectra. We find that TRES-uberMS provides reliable parameter estimates with errors of roughly 100 K in $T_{\rm eff}$, 0.09 dex in $\log g$, and 0.04 dex in [Fe/H] for many nearby dwarf stars, although [Fe/H] performance is poorer for mid-to-late K dwarfs, with the bias worsening with decreasing $T_{\rm eff}$. Performance is also worse for evolved stars. For [$α$/Fe], our error may be as good as 0.03 dex for dwarfs based on external benchmarks, despite sizable and variable systematic differences when comparing with specific alpha-element abundances from other catalogs.

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arXiv2025

The HD 60779 Planetary System: A Transiting Sub-Neptune on a 30-day Orbit and a More Massive Outer World

We present the discovery of the planetary system orbiting the bright (V = 7.2), nearby (35 pc), Sun-like star HD 60779, which has a mass of 1.050 +/- 0.044 solar masses and a radius of 1.129 +/- 0.013 solar radii. We report two TESS transits and a subsequent CHEOPS transit of HD 60779 b, a sub-Neptune with a radius of 3.250 (+0.100 / -0.098) Earth radii on a 29.986175 (+0.000030 / -0.000033) day orbit. Additionally, 286 HARPS-N radial velocity measurements reveal the mass of planet b (14.7 +1.1 / -1.0 Earth masses) and the presence of an outer planet, HD 60779 c, with an orbital period of 104.25 (+0.30 / -0.29) days and a minimum mass (m sin i) of 27.7 +/- 1.6 Earth masses. Both planets' orbits are consistent with being circular, suggesting that they have a dynamically quiet history. The data are not sufficient to determine whether planet c transits. HD 60779's uniquely high systemic radial velocity (129.75 +/- 0.12 km/s) allows its Lyman-alpha emission to avoid absorption by the interstellar medium, making it a prime candidate for probing atmospheric escape from HD 60779 b. HD 60779 is also the third-brightest host of a sub-Neptune with orbital period greater than 25 days and with both mass and radius measured, distinguishing it in terms of accessibility to spectroscopic characterization.

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arXiv2025

A New Brown Dwarf Orbiting an M star and An Investigation on the Eccentricity Distribution of Transiting Long-Period Brown Dwarfs

The orbital eccentricities of brown dwarfs encode valuable information of their formation and evolution history, providing insights into whether they resemble giant planets or stellar binaries. Here, we report the discovery of TOI-5575b, a long-period, massive brown dwarf orbiting a low-mass M5V star ($\rm 0.21\pm0.02\,M_\odot$) delivered by the TESS mission. The companion has a mass and radius of $\rm 72.4\pm4.1\,M_J$ and $\rm 0.84\pm0.07\,R_J$ on a 32-day moderately eccentric orbit ($e=0.187\pm0.002$), making it the third highest-mass-ratio transiting brown dwarf system known to date. Building on this discovery, we investigate the eccentricity distributions of a sample of transiting long-period ($10\leq P\lesssim 1000$ days, $\sim$0.1-1.5 AU) giant planets, brown dwarfs and low-mass stars. We find that brown dwarfs exhibit an eccentricity behavior nearly identical to that of giant planets: a preference for circular orbits with a long tail toward high eccentricities. Such a trend contrasts sharply with direct imaging findings, where cold (5-100 AU) brown dwarfs and giant planets display distinct eccentricity distributions. Our results suggest that transiting long-period brown dwarfs and giant planets probably 1) form in different routes at exterior orbits but undergo analogous dynamical evolution processes and migrate inwards; or 2) both contain two sub-groups, one with widely spread eccentricities while the other has circular orbits, that jointly sculpt the eccentricity distributions. The low-mass-star systems appear to be a distinctive population, showing a peak eccentricity at about 0.3, akin to more massive stellar binaries.

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arXiv2025

An Eccentric Sub-Neptune Moving Into the Evaporation Desert

Though missions such as Kepler, K2, and TESS have discovered $>$2,000 sub-Neptune and Neptunian planets, there is a dearth of such planets at close-in (P$\lesssim$3 days) orbits. This feature, called the Neptune desert or the evaporation desert, is believed to be primarily shaped by planetary migration and photoevaporation. However, this region is not completely devoid of planets--a small number of very hot Neptunes reside within the desert. These planets provide an opportunity to directly probe the effects of migration and photoevaporation. We present confirmation of TOI-5800 b, an eccentric sub-Neptune on a $\approx$2.6 day period that is likely actively undergoing tidal migration. We use radial velocity measurements from the Carnegie Planet Finder Spectrograph (PFS) to constrain TOI-5800 b's mass and eccentricity. We find that it has an unusually high eccentricity (0.39$\pm$0.07) for its short orbit. TOI-5800 is therefore currently experiencing high levels of tidal heating as it moves into the desert. Ranked as a top candidate for transmission and emission spectroscopy within its temperature and radius regime, TOI-5800 b is a prime target for atmospheric characterization with JWST. TOI-5800 b presents a unique opportunity to study the atmosphere of a planet undergoing tidal heating and to probe the composition of sub-Neptune planets.

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arXiv2025

Disentangling Metallicity Effects in Hot Jupiter Occurrence Across Galactic Birth Radius and Phase-Space Density

We explore how the correlation between host star metallicity and giant planets shapes hot Jupiter occurrence as a function of Galactic birth radius (\rbirth) and phase-space density in the Milky Way disk. Using the GALAH and APOGEE surveys and a galaxy from the NIHAO simulation suite, we inject hot Jupiters around stars based on metallicity power laws, reflecting the trend that giant planets preferentially form around metal-rich stars. For \rbirth\ $\geq 5$ kpc, hot Jupiter occurrence decreases with \rbirth\ by $\sim -0.1%$ per kpc; this is driven by the Galaxy's chemical evolution, where the inner regions of the disk are more metal-rich. Differences in GALAH occurrence rates versus APOGEE's and the simulation's at \rbirth\ $< 5$ kpc arise from survey selection effects. APOGEE and the NIHAO simulation have more high-$α$ sequence stars than GALAH, resulting in average differences in metallicity (0.2--0.4 dex), $α$-process element enrichment (0.2 dex), and vertical velocities (7--14 km/s) at each \rbirth\ bin. Additionally, we replicate the result of \cite{Winter20}, which showed that over 92% of hot Jupiters are associated with stars in phase-space overdensities, or "clustered environments." However, our findings suggest that this clustering effect is primarily driven by chemical and kinematic differences between low and high-$α$ sequence star properties. Our results support stellar characteristics, particularly metallicity, being the primary drivers of hot Jupiter formation, which serves as the "null hypothesis" for interpreting planet demographics. This underscores the need to disentangle planetary and stellar properties from Galactic-scale effects in future planet demographics studies.

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arXiv2025

NIRCam yells at cloud: JWST MIRI imaging can directly detect exoplanets of the same temperature, mass, age, and orbital separation as Saturn and Jupiter

NIRCam and MIRI coronagraphy have successfully demonstrated the ability to directly image young sub-Jupiter mass and mature gas-giant exoplanets. However, these modes struggle to reach the sensitivities needed to find the population of cold giant planets that are similar to our own Solar System's giant planets ($T_{\rm eff} = 60 - 125$ K; $a=5 - 30$ AU). For the first time, we explore the high-contrast imaging capabilities of MIRI imaging rather than coronagraphy. Using data from the JWST GO 6122: Cool Kids on the Block program which targets nearby ($<6$ pc) M-dwarfs with NIRCam coronagraphy and MIRI imaging, we demonstrate that 21$μ$m MIRI imaging can detect planets with the same temperature, mass, age, and orbital separations as Saturn and Jupiter. For systems within 3pc, 21$μ$m MIRI imaging reaches the sensitivity needed to detect planets colder than Saturn ($<95$ K). NIRCam coronagraphy can achieve similar results only in the unlikely case that a cold giant planet is cloud-free. Motivated by these compelling findings, we extend our analysis to evaluate the measured performance of MIRI F2100W imaging versus NIRCam F444W coronagraphy to 70 pc and conclude that MIRI imaging offers the advantage for systems within 20pc. Microlensing surveys predict an occurrence rate as high as 1 - 2 low-mass giant exoplanets per star, suggesting that JWST MIRI imaging surveys of nearby systems may be poised to uncover a substantial population. This breakthrough enables a path towards the first direct characterization of cold giant exoplanets that are analogous to the solar system giant planets.

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arXiv2025

The Receding Cosmic Shoreline of Mid-to-Late M Dwarfs: Measurements of Active Lifetimes Worsen Challenges for Atmosphere Retention by Rocky Exoplanets

Detecting and characterizing the atmospheres of terrestrial exoplanets is a key goal of exoplanetary astronomy, one that may now be within reach given the upcoming campaign to conduct a large-scale survey of rocky M-dwarf worlds with the James Webb Space Telescope. It is imperative that we understand where known planets sit relative to the cosmic shoreline, the boundary between planets that have retained atmospheres and those that have not. Previous works modeled the historic XUV radiation received by mid-to-late M-dwarf planets using a scaling relation calibrated using more massive stars, but fully convective M dwarfs display unique rotation/activity histories that differ from Sun-like stars and early M dwarfs. We synthesize observations of the active lifetimes of mid-to-late M dwarfs to present an updated estimate of their historic XUV fluence. For known planets of inactive, mid-to-late M dwarfs, we calculate a historic XUV fluence that is 2.1-3.1 times the canonical XUV scaling relation on average, with the larger value including corrections for the pre-main-sequence phase and energetic flares. We find that only the largest terrestrial planets known to orbit mid-to-late M-dwarfs are likely to have retained atmospheres within the cosmic shoreline paradigm. Our calculations may help to guide the selection of targets for JWST and may prove useful in interpreting the results; to this end, we define a novel Atmosphere Retention Metric (ARM) that indicates the distance between a planet and the cosmic shoreline, and tabulate the ARM for known mid-to-late M-dwarf planets.

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arXiv2025

A Machine-Learning Compositional Study of Exoplanetary Material Accreted Onto Five Helium-Atmosphere White Dwarfs with $\texttt{cecilia}$

We present the first application of the Machine Learning (ML) pipeline $\texttt{cecilia}$ to determine the physical parameters and photospheric composition of five metal-polluted He-atmosphere white dwarfs without well-characterised elemental abundances. To achieve this, we perform a joint and iterative Bayesian fit to their $\textit{SDSS}$ (R=2,000) and $\textit{Keck/ESI}$ (R=4,500) optical spectra, covering the wavelength range from about 3,800Å to 9,000Å. Our analysis measures the abundances of at least two $-$and up to six$-$ chemical elements in their atmospheres with a predictive accuracy similar to that of conventional WD analysis techniques ($\approx$0.20 dex). The white dwarfs with the largest number of detected heavy elements are SDSS J0859$+$5732 and SDSS J2311$-$0041, which simultaneously exhibit O, Mg, Si, Ca, and Fe in their $\textit{Keck/ESI}$ spectra. For all systems, we find that the bulk composition of their pollutants is largely consistent with those of primitive CI chondrites to within 1-2$σ$. We also find evidence of statistically significant ($>2σ$) oxygen excesses for SDSS J0859$+$5732 and SDSS J2311$-$0041, which could point to the accretion of oxygen-rich exoplanetary material. In the future, as wide-field astronomical surveys deliver millions of public WD spectra to the scientific community, $\texttt{cecilia}$ aspires to unlock population-wide studies of polluted WDs, therefore helping to improve our statistical knowledge of extrasolar compositions.

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arXiv2025

TESS Investigation -- Demographics of Young Exoplanets (TI-DYE) III: an inner super-Earth in TOI-2076

Young (<500 Myr) multi-planet transiting systems are valuable environments for understanding planet evolution by offering an opportunity to make direct comparisons between planets from the same formation conditions. TOI-2076 is known to harbor three, 2.5-4 $R_\oplus$ planets on 10-35 day orbits. All three are JWST cycle 3 targets (for transmission spectroscopy). Here, we present the detection of TOI-2076 e; a smaller (1.35 $R_\oplus$), inner (3.02 day) planet in the system. We update the age of the system by analyzing the rotation periods, Lithium equivalent widths, color-magnitude diagram, and variability of likely co-moving stars, finding that TOI-2076 and co-moving planetary system TOI-1807 are 210 $\pm$ 20 Myr. The discovery of TOI-2076 e is motivation to revisit known transiting systems in search of additional planets that are now detectable with new TESS data and updated search methods.

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arXiv2025

Tidally Heated Sub-Neptunes, Refined Planetary Compositions, and Confirmation of a Third Planet in the TOI-1266 System

TOI-1266 is a benchmark system of two temperate ($<$ 450 K) sub-Neptune-sized planets orbiting a nearby M dwarf exhibiting a rare inverted architecture with a larger interior planet. In this study, we characterize transit timing variations (TTVs) in the TOI-1266 system using high-precision ground-based follow-up and new TESS data. We confirm the presence of a third exterior non-transiting planet, TOI-1266 d (P = 32.5 d, $M_d$ = 3.68$^{+1.05}_{-1.11} M_{\oplus}$), and combine the TTVs with archival radial velocity (RV) measurements to improve our knowledge of the planetary masses and radii. We find that, consistent with previous studies, TOI-1266 b ($R_b$ = 2.52 $\pm$ 0.08 $R_{\oplus}$, $M_b$ = 4.46 $\pm$ 0.69 $M_{\oplus}$) has a low bulk density requiring the presence of a hydrogen-rich envelope, while TOI-1266 c ($R_c$ = 1.98 $\pm$ 0.10 $R_{\oplus}$, $M_c$ = 3.17 $\pm$ 0.76 $M_{\oplus}$) has a higher bulk density that can be matched by either a hydrogen-rich or water-rich envelope. Our new dynamical model reveals that this system is arranged in a rare configuration with the inner and outer planets located near the 3:1 period ratio with a non-resonant planet in between them. Our dynamical fits indicate that the inner and outer planet have significantly nonzero eccentricities ($e_b + e_d = 0.076^{+0.029}_{-0.019}$), suggesting that TOI-1266 b may have an inflated envelope due to tidal heating. Finally, we explore the corresponding implications for the formation and long-term evolution of the system, which contains two of the most favorable cool ($<$ 500 K) sub-Neptunes for atmospheric characterization with JWST.

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arXiv2025

Thermal Emission and Confirmation of the Frigid White Dwarf Exoplanet WD 1856+534b

We report the detection of thermal emission from and confirm the planetary nature of WD 1856+534b, the first transiting planet known to orbit a white dwarf star. Observations with JWST's Mid-Infrared Instrument (MIRI) reveal excess mid-infrared emission from the white dwarf, consistent with a closely-orbiting Jupiter-sized planet with a temperature of $186^{+6}_{-7}$ K. We attribute this excess flux to the known giant planet in the system, making it the coldest exoplanet from which light has ever been directly observed. These measurements constrain the planet's mass to no more than six times that of Jupiter, confirming its planetary nature and ruling out previously unexcluded low-mass brown dwarf scenarios. WD 1856+534b is now the first intact exoplanet confirmed within a white dwarf's "forbidden zone", a region where planets would have been engulfed during the star's red giant phase. Its presence provides direct evidence that planetary migration into close orbits, including the habitable zone, around white dwarfs is possible. With an age nearly twice that of the Solar System and a temperature akin to our own gas giants, WD 1856+534b demonstrates JWST's unprecedented ability to detect and characterize cold, mature exoplanets, opening new possibilities for imaging and characterizing these worlds in the solar neighborhood.

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arXiv2025

TOI-2005b: An Eccentric Warm Jupiter in Spin-Orbit Alignment

We report the discovery and characterization of TOI-2005b, a warm Jupiter on an eccentric (e~0.59), 17.3-day orbit around a V_mag = 9.867 rapidly rotating F-star. The object was detected as a candidate by TESS and the planetary nature of TOI-2005b was then confirmed via a series of ground-based photometric, spectroscopic, and diffraction-limited imaging observations. The planet was found to reside in a low sky-projected stellar obliquity orbit (lambda = 4.8 degrees) via a transit spectroscopic observation using the Magellan MIKE spectrograph.TOI-2005b is one of a few planets known to have a low-obliquity, high-eccentricity orbit, which may be the result of high-eccentricity coplanar migration. The planet has a periastron equilibrium temperature of ~ 2100 K, similar to some highly irradiated hot Jupiters where atomic metal species have been detected in transmission spectroscopy, and varies by almost 1000 K during its orbit. Future observations of the atmosphere of TOI-2005b can inform us about its radiative timescales thanks to the rapid heating and cooling of the planet.

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arXiv2025

A Disintegrating Rocky Planet with Prominent Comet-like Tails Around a Bright Star

We report the discovery of BD+05$\,$4868$\,$Ab, a transiting exoplanet orbiting a bright ($V=10.16$) K-dwarf (TIC 466376085) with a period of 1.27 days. Observations from NASA's Transiting Exoplanet Survey Satellite (TESS) reveal variable transit depths and asymmetric transit profiles that are characteristic of comet-like tails formed by dusty effluents emanating from a disintegrating planet. Unique to BD+05$\,$4868$\,$Ab is the presence of prominent dust tails in both the trailing and leading directions that contribute to the extinction of starlight from the host star. By fitting the observed transit profile and analytically modeling the drift of dust grains within both dust tails, we infer large grain sizes ($\sim1-10\,μ$m) and a mass loss rate of $10\,M_{\rm \oplus}\,$Gyr$^{-1}$, suggestive of a lunar-mass object with a disintegration timescale of only several Myr. The host star is probably older than the Sun and is accompanied by an M-dwarf companion at a projected physical separation of 130 AU. The brightness of the host star, combined with the planet's relatively deep transits ($0.8-2.0\%$), presents BD+05$\,$4868$\,$Ab as a prime target for compositional studies of rocky exoplanets and investigations into the nature of catastrophically evaporating planets.

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arXiv2025

The Ambiguous Age and Tidal History for the Ultra-Hot Jupiter TOI-1937Ab

Ultra-short-period (USP) planets are a rare but dynamically significant subset of the exoplanet sample, and understanding their dynamical histories and migration processes is necessary to build a complete picture of the outcomes of planet formation. In this work, we present an analysis of system age constraints and the impact of tidal evolution in the TOI-1937A system, a component of a large-separation stellar binary with an ambiguous age constraint that hosts a massive (> 2 $M_{Jup}$) USP planetary companion. Through a suite of tidal evolution simulations and analysis of the transit timing variations present in the photometric data, we find that the ultra-hot Jupiter TOI-1937Ab is likely undergoing orbital decay driven by tidal interactions, and we place an observational upper limit on its decay rate of |$\dot{P}$| < 0.09. We consider three different hypotheses for the system age based on three distinct methods of age estimation. These three age limits are complemented by indirect evidence of the age of the star that comes from our dynamical and transit timing analyses. We discuss the possibility that future data will provide more concrete constraints on the tidal parameters of TOI-1937Ab and its host star.

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arXiv2025

Asteroseismic Study of Subgiants and Giants of the Open Cluster M67 using Kepler/K2: Expanded Sample and Precise Masses

Sparked by the asteroseismic space revolution, ensemble studies have been used to produce empirical relations linking observed seismic properties and fundamental stellar properties. Cluster stars are particularly valuable because they have the same metallicity, distance, and age, thus reducing scatter to reveal smoother relations. We present the first study of a cluster that spans the full evolutionary sequence from subgiants to core helium-burning red giants using asteroseismology to characterise the stars in M67, including a yellow straggler. We use Kepler/K2 data to measure seismic surface gravity, examine the potential influence of core magnetic fields, derive an empirical expression for the seismic surface term, and determine the phase term $ε$ of the asymptotic relation for acoustic modes, extending its analysis to evolutionary states previously unexplored in detail. Additionally, we calibrate seismic scaling relations for stellar mass and radius, and quantify their systematic errors if surface term corrections are not applied to state-of-the-art stellar models. Our masses show that the Reimers mass loss parameter can not be larger than $η$ $\sim$ 0.23 at the 2-$σ$ level. We use isochrone models designed for M67 and compare their predictions with individual mode frequencies. We find that the seismic masses for subgiants and red giant branch stars align with the isochrone-predicted masses as per their luminosity and colour. However, our results are inconsistent with the mass of one of the stellar components of an eclipsing binary system near the TAMS. We use traditional seismic $χ^2$ fits to estimate a seismic cluster age of 3.95 $\pm$ 0.35 Gyrs.

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