The scarcity of high-fidelity extinction measurements remains a bottleneck in deriving accurate stellar properties from Gaia parallaxes. In this work, we aim to derive precise extinction estimates for Apache Point Observatory Galactic Evolution Experiment (APOGEE) data release 19 stars, establishing a new benchmark for Galactic stellar population studies. We first determine reddening by comparing observed colours-retrieved from photometric surveys or standardized synthetic magnitudes from Gaia low-resolution blue and red photometer (BP/RP) spectra-to intrinsic colours predicted via an XGBOOST model. The model is trained on minimally reddened stars to infer intrinsic colours and their associated uncertainties, using APOGEE stellar parameters (T-eff, log(g), [Fe/H], and [alpha/Fe]). The derived reddening values are then converted into extinctions using an anchor ratio of A(BP) /A(RP) = 1 . 694 +/- 0.004 , derived from red-clump-like stars. Here, we provide extinction measurements in 39 filters across 10 photometric systems and introduce a new empirical extinction curve optimized for broadband passbands. Our extinction estimates ( A(V) ) outperform existing results (Bayestar19, StarHorse, SEDEX), achieving a typical precision of similar to 0.03 mag in A(V) . Notably, we identify systematic deviations of up to 30 per cent between monochromatic and passband-integrated extinction ratios at wavelengths lambda > 700 nm. This result highlights the necessity of adopting passband-specific coefficients when correcting extinction to derive stellar parameters. The derived extinction and reddening data are available to the community for download.

Globular clusters provide unique opportunities to study stellar evolution - as the second brightest cluster, 47 Tuc is a prime target. Asteroseismology can be used to measure precise masses of stars and has recently been applied to red giants in globular clusters, but so far not for 47 Tuc. Here, we present a search for solar-like oscillations in red giants of 47 Tuc using 8.3 d of high-cadence Hubble Space Telescope data. We detect oscillations in two out of the five giants falling in the field of view. One is on the horizontal branch (HB) while the other is on the red giant branch (RGB) at a similar brightness. From the seismic signal, we measure the stellar masses to be 0.78 +/- 0.13M(circle dot) (HB) and 0.94 +/- 0.15M(circle dot) (RGB), and hence an inferred integrated mass-loss along the upper RGB of 0.16 +/- 0.20M(circle dot). A mass uncertainty of less than 0.05 M-circle dot would be required to obtain a useful estimate of the mass-loss, while an uncertainty below 0.01 M-circle dot would be required to measure the mass difference between the cluster's multiple chemical populations. The former would be attainable with observations of about 100 times more stars to form ensemble-averaged values, or alternatively a longer campaign observing fewer stars. Detecting mass differences between the chemical sub-populations, could be obtained with a 20-d campaign observing several hundreds of stars. Our clear detection of oscillations and the prospects presented here warrant dedicated high-cadence campaigns of 47 Tuc, which are possible with NASA's Roman mission and future missions like HAYDN.

Open clusters are fundamental laboratories for investigating stellar and Galactic evolution, and serve as important benchmarks for asteroseismic analyses. Using a “boutique” method to analyze TESS photometry, we study red giants in two old supersolar-metallicity open clusters: NGC 188 and NGC 6791. By comparing Kepler Space Telescope (Kepler) and TESS observations for NGC 6791, similar oscillation mode frequencies are recovered, however we find a systematic offset of 2.2% with a scatter of 9% in the ν _max measurements. We attribute this discrepancy to the lower signal-to-noise ratio of the TESS data for these relatively faint stars. For the brighter cluster NGC 188, we present new seismic measurements in 17 red giants. We estimate average seismic masses for the red giant branch (RGB) of M _RGB,NGC 188 = 1.13 ± 0.04(rand.) ${}_{-0.19}^{+0.12}$ (sys.) M _⊙ and red clump of M _RC,NGC 188 = 1.11 ± 0.01(rand.) ${}_{-0.19}^{+0.11}$ (sys.) M _⊙ , consistent with independent mass estimates for this cluster and with similar precision to previous Kepler studies. From the difference between the average evolutionary phase masses, we estimate an integrated RGB mass loss of Δ M = 0.02 ± 0.04(rand.) ± 0.01(sys.) M _⊙ , supporting the evidence for lower mass loss at higher metallicities. Using asteroseismology and chemical abundances, we identify three binary interaction candidates: two undermassive stars and one overmassive star potentially exhibiting dipole-mode suppression. Finally, we derive an average seismic cluster age of 7.0 ± 0.9 Gyr, in good agreement with previous literature ages. Our analysis demonstrates the strong potential of TESS asteroseismology for open clusters, and motivates extending this investigation to other TESS clusters that span a wider range of ages and metallicities.

TESS (Transiting Exoplanet Survey Satellite) has produced long-term photometry for millions of stars across the sky. In this work, we present an asteroseismic catalogue of 19,151 red giants in the TESS Continuous Viewing Zones using sectors 1–87 (Years 1–7). We visually assessed the power spectra for oscillations, and then applied the computationally efficient nuSYD method to confirm reliability. We identified an increase of 80

We present resolutions as to the nature of six speculative candidate companions proposed in the final data release of the Pan-Pacific Planet Search, a 6-yr radial-velocity survey of 164 southern evolved stars using the now-decommissioned University College London Echelle Spectrograph (UCLES) on the 3.9m Anglo-Australian Telescope (AAT). New radial-velocity observations, TESS asteroseismology, and Hipparcos-Gaia astrometry are incorporated to refine the companion and host-star parameters. We confirm that HD 126105b is a giant planet (P = 524.0 +/- 2.9 d, m sin i = 1.67(-0.17)(+0.19) M-J), and that HD 205577B is a massive, eccentric brown dwarf ( P similar to 11.2 yr, m = 77(-9)(+11) M-J, e = 0.68). HD 115066B and HD 121156B are low-mass stellar companions, while HD 114899 and HD 159743 are shown to be unadorned by any detectable companions whatsoever. This demonstrates the utility of astrometric information to help overcome the temporal limitations of incomplete radial-velocity data sets and elucidate the true nature of suspected companion bodies.

Open clusters are fundamental laboratories for investigating stellar and Galactic evolution, and serve as important benchmarks for asteroseismic analyses. Using a boutique method to analyze TESS photometry, we study red giants in two old metal-rich open clusters: NGC 188 NGC 6791. By comparing Kepler and TESS observations for NGC 6791, similar oscillation mode frequencies are recovered, however we find a systematic offset of 2.2

Transiting Exoplanet Survey Satellite (TESS) has produced long-term photometry for millions of stars across the sky. In this work, we present an asteroseismic catalogue of 19 151 red giants in the TESS Continuous Viewing Zones using sectors 1-87 (Years 1-7). We visually assessed the power spectra for oscillations, and then applied the computationally efficient nuSYD method to confirm reliability. We identified an increase of 80 per cent in the number of previously known oscillating red giants at a TESS magnitude > 8. We determined the frequency of maximum power (v(max)) and the large frequency separation (Av) using the pySYD pipeline, achieving typical precisions of 1.5 per cent and 1.0 per cent, respectively. We classified the stars into red giant branch (RGB) and Core Helium Burning (CHeB) classes using a convolutional neural network. Using spectroscopic data for 10 298 stars with reliable asteroseismic measurements, we have been able to measure stellar mass and radii with precisions of 7.5 per cent and 2.8 per cent, which is comparable to that from 4-yr Kepler data. A comparison of the seismic radii with Gaia radii shows excellent agreement. With 3 yr of TESS data, the asteroseismic parameters are precise enough to identify the RGB bump and delineate the Zero Age Helium Burning edge. Combined with astrometric data, these parameters reveal established trends across the Galactic plane, providing a valuable set of uniformly determined asteroseismic parameters for Galactic Archaeology.

We present a comprehensive data-driven spectroscopic analysis of 357,415 red giant stars using Gaia DR3 Radial Velocity Spectrometer (RVS) spectra (8460-8700 A; R≈11,500), aimed at deriving homogenous stellar parameters and elemental abundances (collectively referred to as stellar labels). We employ The Cannon, a generative model based on 2747 giants in common with GALactic Archaeology with HERMES (GALAH) DR4, adopting GALAH labels (R≈28,000) for training. The resulting model predicts 11 stellar labels for RVS giants: effective temperature (T_ eff), surface gravity (log g), projected rotational velocity (vsin i), and abundances of [Fe/H], [Ca/Fe], [Si/Fe], [Ni/Fe], [Ti/Fe], as well as the neutron-capture elements [Zr/Fe], [Ce/Fe], and [Nd/Fe]. Building on these results, we develop a probabilistic framework to chemically identify debris from the Gaia-Sausage-Enceladus (GSE) accretion event. A logistic regression classifier, optimized via Markov chain Monte Carlo sampling and trained on a small reference sample of GSE members and comparison stars, identifies stars with high GSE membership probabilities based solely on their chemical abundances, with the resulting candidates exhibiting distinctive abundance-ratio patterns, including [Ca/Ti], [Ti/Ce], and [Nd/Zr]. Applying independent kinematic constraints yields a robust sample of GSE candidates, demonstrating that the characteristic chemical signatures remain consistent after applying these constraints. This work demonstrates the potential of data-driven analysis techniques to extract detailed chemical information from medium-resolution spectra and establishes a framework for tracing Galactic accretion events using chemical abundances.

The high-mass (M > 2M(circle dot)) Kepler red giant stars are less well-studied than their lower mass counterparts. In the previous article, we presented a sample of 48 high-mass Kepler red giants and measured their asteroseismic parameters. This article presents spectroscopic measurements from the same sample, using high-resolution Keck/HIRES spectra to determine T-eff. [Fe/H], logg. and v sini. We refined our previous estimates of the stellar masses and radii based on the new T-eff. We also examined spectral features that could indicate binary activity, such as the Li line and [C/N] ratios. We found no Li-rich stars or clear [C/N] anomalies, but we observed a correlation between [C/N] and [Fe/H]. We measured chromospheric activity using the S-index of the Ca 11 H & K lines and found no correlation with internal magnetic fields. However, we confirmed an anticorrelation. between surface chromospheric activity and radial mode oscillation amplitudes, which indicates that strong surface magnetic fields weaken stellar oscillations. Finally, we used the Gaia DR3 astrometric data to show that our sample of stars have orbits consistent with all three Galactic kinematic regions. Although these stars are quite young, their orbits carry them into the thick disc and even the halo, raising questions about the accuracy and viability of kinematics in unravelling Galactic history. In future work, we plan to use the spectroscopic parameters measured here to provide better constraints for boutique frequency modelling. which will allow us to test the asteroseismic scaling relations at the high-mass regime. Key words: stars: atmospheres-stars: chromospheres-stars: horizontal branch-stars: kinematics and dynamics-stars: oscillations-stars: variables: general.

Context. Metal-poor stars play a crucial role in understanding the nature and evolution of the first stellar generation in the Galaxy. Previously, asteroseismic characterisation of red-giant stars has relied on constraints from the global asteroseismic parameters and not the full spectrum of individual oscillation modes. Using the latter, we present for the first time the characterisation of two evolved very metal-poor stars including the detail-rich mixed-mode patterns. Aims. We will demonstrate that incorporating individual frequencies into grid-based modelling of red-giant stars enhances its precision, enabling detailed studies of these ancient stars and allowing us to infer the stellar properties of two very metal-poor [Fe/H] similar to -2.5 dex Kepler stars: KIC 4671239 and KIC 7693833. Methods. Recent developments in both observational and theoretical asteroseismology have allowed for detailed studies of the complex oscillation pattern of evolved giants. In this work, we employ Kepler timeseries and surface properties from high-resolution spectroscopic data within a grid-based modelling approach to asteroseismically characterise KIC 4671239 and KIC 7693833 using the BAyesian STellar Algorithm, BASTA. Results. Both stars show agreement between constraints from seismic and classical observables, an overlap unrecoverable when purely considering the global asteroseismic parameters. KIC 4671239 and KIC 7693833 were determined to have masses of 0.78(-0.03)(+0.04)and 0.83(-0.01)(+0.03)Mwith ages of12.1(-1.5)(+1.6)and 10.3(-1.4)(+0.6)Gyr, respectively. Particularly, for KIC 4671239 the rich spectrum of model frequencies closely matches the observed. Conclusions. A discrepancy between the observed and modelled nu max of similar to 10% was found, indicating a metallicity dependence of the nu max scaling relation. For metal-poor populations, this results in overestimations of the stellar masses and wrongful age inferences. Utilising the full spectra of individual oscillation modes lets us circumvent the dependence on the asteroseismic scaling relations through direct constraints on the stars themselves. This allows us to push the boundaries of state-of-the-art detailed modelling of evolved stars at metallicities far different from solar.

On the main sequence, the asteroseismic small frequency separation delta nu 02 between radial and quadrupole p-modes is customarily interpreted to be a direct diagnostic of internal structure. Such an interpretation is based on a well-known integral estimator relating delta nu 02 to a radially averaged sound-speed gradient. However, this estimator fails, catastrophically, when evaluated on structural models of red giants: their small separations must therefore be interpreted differently. We derive a single expression that both reduces to the classical estimator when applied to main-sequence stellar models and reproduces the qualitative features of the small separation for stellar models of very evolved red giants. This expression indicates that the small separations of red giants scale primarily with their global seismic properties as delta nu 02 proportional to Delta nu 2/nu max , rather than being in any way sensitive to their internal structure. Departures from this asymptotic behavior, during the transition from the main-sequence to red giant regimes, have been recently reported in open-cluster Christensen-Dalsgaard (C-D) diagrams from K2 mission data. Investigating them in detail, we demonstrate that they occur when the convective envelope boundary passes a specific acoustic distance-roughly one-third of a wavelength at nu max -from the center of the star, at which point radial modes become maximally sensitive to the position of the boundary. The shape of the corresponding features on & varepsilon;p and C-D (or r02) diagrams may be useful in constraining the nature of convective boundary mixing in the context of undershooting beneath a convective envelope.

The stars of the Milky Way carry the chemical history of our Galaxy in their atmospheres as they journey through its vast expanse. Like barcodes, we can extract the chemical fingerprints of stars from high-resolution spectroscopy. The fourth data release (DR4) of the Galactic Archaeology with HERMES (GALAH) Survey, based on a decade of observations, provides the chemical abundances of up to 32 elements for 917 588 stars that also have exquisite astrometric data from the Gaia satellite. For the first time, these elements include life-essential nitrogen to complement carbon, and oxygen as well as more measurements of rare-earth elements critical to modern-life electronics, offering unparalleled insights into the chemical composition of the Milky Way. For this release, we use neural networks to simultaneously fit stellar parameters and abundances across the whole wavelength range, leveraging synthetic grids computed with Spectroscopy Made Easy. These grids account for atomic line formation in non-local thermodynamic equilibrium for 14 elements. In a two-iteration process, we first fit stellar labels to all 1 085 520 spectra, then co-add repeated observations and refine these labels using astrometric data from Gaia and 2MASS photometry, improving the accuracy and precision of stellar parameters and abundances. Our validation thoroughly assesses the reliability of spectroscopic measurements and highlights key caveats. GALAH DR4 represents yet another milestone in Galactic archaeology, combining detailed chemical compositions from multiple nucleosynthetic channels with kinematic information and age estimates. The resulting dataset, covering nearly a million stars, opens new avenues for understanding not only the chemical and dynamical history of the Milky Way but also the broader questions of the origin of elements and the evolution of planets, stars, and galaxies.

In the third APOKASC catalog, we present data for the complete sample of 15,808 evolved stars with APOGEE spectroscopic parameters and Kepler asteroseismology. We used 10 independent asteroseismic analysis techniques and anchor our system on fundamental radii derived from Gaia L and spectroscopic Teff. We provide evolutionary state, asteroseismic surface gravity, mass, radius, age, and the data used to derive them for 12,418 stars. This includes 10,036 exceptionally precise measurements, with median fractional uncertainties in nu max , Delta nu, mass, radius, and age of 0.6%, 0.6%, 3.8%, 1.8%, and 11.1%, respectively. We provide more limited data for 1624 additional stars that either have lower-quality data or are outside of our primary calibration domain. Using lower red giant branch (RGB) stars, we find a median age for the chemical thick disk of 9.14 +/- 0.05(ran) +/- 0.9(sys) Gyr with an age dispersion of 1.1 Gyr, consistent with our error model. We calibrate our red clump (RC) mass loss to derive an age consistent with the lower RGB and provide asymptotic GB and RGB ages for luminous stars. We also find a sharp upper-age boundary in the chemical thin disk. We find that scaling relations are precise and accurate on the lower RGB and RC, but they become more model dependent for more luminous giants and break down at the tip of the RGB. We recommend the use of multiple methods, calibration to a fundamental scale, and the use of stellar models to interpret frequency spacings.

Acoustic oscillations in stars are sensitive to stellar interiors1. Frequency differences between overtone modes-large separations-probe stellar density2, whereas differences between low-degree modes-small separations-probe the sound-speed gradient in the energy-generating core of main-sequence Sun-like stars3, and hence their ages. At later phases of stellar evolution, characterized by inert cores, small separations are believed to lose much of their power to probe deep interiors and become proportional to large separations4,5. Here we present evidence of a rapidly evolving convective zone as stars evolve from the subgiant phase into red giants. By measuring acoustic oscillations in 27 stars from the open cluster M67, we observe deviations of proportionality between small and large separations, which are caused by the influence of the bottom of the convective envelope. These deviations become apparent as the convective envelope penetrates deep into the star during subgiant and red giant evolutions, eventually entering an ultradeep regime that leads to the red-giant-branch luminosity bump. The tight sequence of cluster stars, free of large spreads in ages and fundamental properties, is essential for revealing the connection between the observed small separations and the chemical discontinuities occurring at the bottom of the convective envelope. We use this sequence to show that combining large and small separations can improve estimations of the masses and ages of field stars well after the main sequence.

Modern spectroscopic surveys output large data volumes. Theoretical models provide a means to transform the information encoded in these data to measurements of physical stellar properties. However, in detail, the models are incomplete and simplified, and prohibit interpretation of the fine details in spectra. Instead, the available data provide an opportunity to use data-driven, differential analysis techniques, as a means towards understanding spectral signatures. We deploy such an analysis to examine core helium-fusing red clump (RC) and shell hydrogen-fusing red giant branch (RGB) stars, to uncover signatures of evolutionary state imprinted in optical stellar spectra. We exploit 786 pairs of RC and RGB stars from the GALAH survey, chosen to minimize spectral differences, with evolutionary state classifications from TESS and K2 asteroseismology. We report sub-per cent residual, systematic spectral differences between the two classes of stars, and show that these residuals are significant compared to a reference sample of RC-RC and RGB-RGB pairs selected using the same criteria. First, we report systematic differences in the Swan (C (2) ) band and CN bands caused by stellar evolution and a difference in mass, where RGB stars at similar stellar parameters have higher masses than RC stars. Secondly, we observe systematic differences in the line-width of the H (alpha) and H (beta) lines caused by a difference in microturbulence, as measured by GALAH, where we measure higher microturbulence in RC stars than RGB stars. This work demonstrates the ability of large surveys to uncover the subtle spectroscopic signatures of stellar evolution using model-free, data-driven methods.

Large spectroscopic surveys aim to consistently compute stellar parameters of very diverse stars while minimizing systematic errors. We explore the use of stellar clusters as benchmarks to verify the precision of spectroscopic parameters in the 4. data release (DR4) of the GALAH survey. We examine 58 open and globular clusters and associations to validate measurements of temperature, gravity, chemical abundances, and stellar ages. We focus on identifying systematic errors and understanding trends between stellar parameters, particularly temperature and chemical abundances. We identify trends by stacking measurements of chemical abundances against effective temperature and modelling them with splines. We also refit spectra in three clusters with the Spectroscopy Made Easy and Korg packages to reproduce the trends in DR4 and to search for their origin by varying temperature and gravity priors, linelists, and spectral continuum. Trends are consistent between clusters of different ages and metallicities, can reach amplitudes of 0.5 dex and differ for dwarfs and giants. We use the derived trends to correct the DR4 abundances of 24 and 31 chemical elements for dwarfs and giants, and publish a detrended catalogue. While the origin of the trends could not be pinpointed, we found that: i) photometric priors affect derived abundances, ii) temperature, metallicity, and continuum levels are degenerate in spectral fitting, and it is hard to break the degeneracy even by using independent measurements, iii) the completeness of the linelist used in spectral synthesis is essential for cool stars, and iv) different spectral fitting codes produce significantly different iron abundances for stars of all temperatures. We conclude that clusters can be used to characterise the systematic errors of parameters produced in large surveys, but further research is needed to explain the origin of the trends.

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 characterize 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 & varepsilon; 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 cannot be larger than eta similar to 0.23 at the 2 sigma 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 cluster turnoff. We use traditional seismic chi(2) fits to estimate a seismic cluster age of 3.95 +/- 0.35Gyr.

We present time-series radial velocities of the G8 subgiant star beta Aql obtained in 2022 and 2023 using SONG-Tenerife and, for the first time, SONG-Australia. We also analyse a sector of TESS photometry that overlapped with the 2022 SONG data. The resulting power spectrum clearly shows solar-like oscillations centred at 430 muHz. The TESS light curve shows the oscillations at lower signal-to-noise, reflecting the fact that photometric measurements are much more affected by the granulation background than are radial velocities. The simultaneous observations in velocity and photometry represent the best such measurements for any star apart from the Sun. They allowed us to measure the ratio between the bolometric photometric amplitude and the velocity amplitude to be 26.6 +/- 3.1 ppm/(m/s). We measured this ratio for the Sun from published SOHO data to be 19.5 +/- 0.7 ppm/(m/s) and, after accounting for the difference in effective temperatures of and the Sun, these values align with expectations. In both the Sun and beta Aql, the photometry-to-velocity ratio appears to be a function of frequency. We also measured the phase shift of the oscillations in beta Aql between SONG and TESS to be -113 +/- 7 deg, which agrees with the value for the Sun and also with a 3-D simulation of a star with similar properties to beta Aql. Importantly for exoplanet searches, we argue that simultaneous photometry can be used to predict the contribution of oscillations to radial velocities. We measured frequencies for 22 oscillation modes in beta Aql and carried out asteroseismic modelling, yielding an excellent fit to the frequencies. We derived accurate values for the mass and age, and were able to place quite strong constraints on the mixing-length parameter. Finally, we show that the oscillation properties of beta Aql are very similar to stars in the open cluster M67.

Metal-poor stars are key to understanding the first stellar generation in the Galaxy. Asteroseismic characterisation of red giants has traditionally relied on global seismic parameters, not the full spectrum of individual oscillation modes. Here, we present the first characterisation of two evolved very metal-poor stars, including the detailed mixed-mode patterns. We demonstrate that incorporating individual frequencies into grid-based modelling of red-giant stars enhances its precision, enabling detailed studies of these ancient stars and allowing us to infer the stellar properties of two [Fe/H]∼-2.5 dex Kepler stars: KIC 4671239 and KIC 7693833. Recent developments in both observational and theoretical asteroseismology allows for detailed studies of the complex oscillation pattern of evolved giants. We employ Kepler time series and surface properties from high-resolution spectroscopic data to asteroseismically characterise the two stars using the BAyesian STellar Algorithm, BASTA. Both stars show agreement between constraints from seismic and classical observables; an overlap unrecoverable when purely considering the global seismic parameters. KIC 4671239 and KIC 7693833 were determined to have masses of 0.78^+0.04_-0.03 and 0.83^+0.03_-0.01 M_⊙ with ages of 12.1^+1.6_-1.5 and 10.3^+0.6_-1.4 Gyr, respectively. A ∼10 discrepancy between observed and modelled ν_max suggests a metallicity dependence of its scaling relation, leading to overestimated masses and incorrect age inferences for metal-poor stars. Utilising the full spectrum of individual oscillation modes, we circumvent the dependence on the asteroseismic scaling relations, providing direct constraints on the stars themselves, pushing the boundaries of state-of-the-art detailed modelling of evolved stars at metallicities far different from solar.

Context. Evolved cool stars have three distinct evolutionary status: shell-hydrogen burning (RGB), core-helium and shell-hydrogen burning (RC), and double-shell burning (AGB). Asteroseismology can distinguish between the RC and the other status, but distinguishing RGB and AGB has been difficult seismically and spectroscopically. The precise boundaries of different status in the Hertzprung-Russel (HR) diagram have also been difficult to establish. Aims. In this article we present a comprehensive catalog of asteroseismic evolutionary status, RGB and RC, for evolved red giants in the Kepler field. To prepare this catalog we carefully examined boundary cases to define the lower edge of the RC phase in radius and surface gravity. We also tested different published asteroseisemic methods claiming to distinguish AGB and RGB stars against a sample where AGB candidates were selected using a spectrocopic identification method. Methods. We used six different seismic techniques to distinguish RC and RGB stars, and tested two proposed methods for distinguishing between AGB and RGB stars. These status were compared with those inferred from spectroscopy. Results. We present consensus evolutionary status for 18 784 stars out of the 30 337 red giants present in the Kepler data, including 11 516 stars with APOGEE spectra available. The agreement between seismic and spectroscopic classification is excellent for distinguishing RC stars, agreeing at the 94% level. Most disagreements can be traced to uncertainties in spectroscopic parameters, but some are caused by blends with background stars. We find a sharp lower boundary in surface gravity at log(g) = 2.99 +/- 0.01 for the RC and discuss the implications. We demonstrate that asteroseismic tools for distinguishing between AGB and RGB stars are consistent with the spectroscopic evolutionary status at near the RC (with the asteroseismic large separation Delta nu <= 2 mu Hz), but that the agreement between the different methods decreases rapidly as the star evolves during the AGB phase. Conclusions. This work presents the most complete evolutionary status catalog for Kepler and APOGEE red giant stars. The data precisely defines the locus of RC stars in the HR diagram, an important constraint for stellar theory and stellar populations. We also demonstrate that asteroseismic tools can distinguish between AGB and RGB stars under some circumstances, which is important for the age estimation of field stars. However, we also put forward the importance of using several techniques to assess the evolutionary status determination for luminous red giants.