The K2 Galactic Archaeology Program Data Release 2: Asteroseismic Results from Campaigns 4, 6, and 7

Zinn, Joel; Stello, Dennis; Elsworth, Y.; García, R. A.; Kallinger, T.; Mathur, S.; Mosser, B.; Bugnet, L.; Jones, C.; Hon, Marc; Sharma, Sanjib; Schönrich, Ralph; Warfield, Jack T.; Luger, Rodrigo; Pinsonneault, Marc H.; Johnson, Jennifer A.; Huber, Daniel; Aguirre, V. Silva; Chaplin, W. J.; Davies, G. R.; Miglio, A.

doi:10.3847/1538-4365/abbee3

Cited by 39 publications

(40 citation statements)

References 72 publications

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“…Additionally, the available asteroseismic information is growing steadily as the analysis of data from the K2 campaigns progresses. The overlap between GALAH targets and K2 targets from campaign C1-C8 and C10-C18 has increased to more than 10 000 stars with measured asteroseismic max values (Zinn et al 2020) and spectroscopic information, and covers almost the entire red giant branch (log ∼1.5 − 3.0 dex) and helium-core burning red clump.…”

Section: Target Selectionmentioning

confidence: 99%

The GALAH+ survey: Third data release

Buder

Sharma

Kos

et al. 2021

Monthly Notices of the Royal Astronomical Society

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464

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The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the Milky Way. With this third data release of the Galactic Archaeology with HERMES (GALAH) survey, we publish 678 423 spectra for 588 571 mostly nearby stars (81.2% of stars are within < 2 kpc), observed with the HERMES spectrograph at the Anglo-Australian Telescope. This release (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1 (bright, main, and faint survey, 70%), K2-HERMES (17%), TESS-HERMES (5%), and a subset of ancillary observations (8%) including the bulge and > 75 stellar clusters. We derive stellar parameters Teff, log g, [Fe/H], vmic, vbroad, and vradusing our modified version of the spectrum synthesis code Spectroscopy Made Easy (sme) and 1D marcs model atmospheres. We break spectroscopic degeneracies in our spectrum analysis with astrometry from Gaia DR2 and photometry from 2MASS. We report abundance ratios [X/Fe] for 30 different elements (11 of which are based on non-LTE computations) covering five nucleosynthetic pathways. We describe validations for accuracy and precision, flagging of peculiar stars/measurements and recommendations for using our results. Our catalogue comprises 65% dwarfs, 34% giants, and 1% other/unclassified stars. Based on unflagged chemical composition and age, we find 62% young low-α, 9% young high-α, 27% old high-α, and 2% stars with [Fe/H] ≤ −1. Based on kinematics, 4% are halo stars. Several Value-Added-Catalogues, including stellar ages and dynamics, updated after GaiaeDR3, accompany this release and allow chrono-chemodynamic analyses, as we showcase.

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Section: Target Selectionmentioning

confidence: 99%

The GALAH+ survey: Third data release

Buder

Sharma

Kos

et al. 2021

Monthly Notices of the Royal Astronomical Society

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464

295

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“…The comparison of the results obtained by the three seismic pipelines (A2Z, COR, and pySYD) allowed us to build a list of confirmed detections constituted of 99 stars where at least two pipelines agree within 10% in ν max , as it has already been demonstrated that such scatter between pipelines is reasonable, particularly for low S/N cases (e.g., Zinn et al 2020). In the remainder of the paper, we refer to those 99 stars as "our sample.…”

Section: Finalizing the Sample Of Confirmed Detectionsmentioning

confidence: 99%

Detections of solar-like oscillations in dwarfs and subgiants with Kepler DR25 short-cadence data

Mathur

García

Breton

et al. 2021

A&A

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During the survey phase of the Kepler mission, several thousand stars were observed in short cadence, allowing for the detection of solar-like oscillations in more than 500 main-sequence and subgiant stars. These detections showed the power of asteroseismology in determining fundamental stellar parameters. However, the Kepler Science Office discovered an issue in the calibration that affected half of the store of short-cadence data, leading to a new data release (DR25) with corrections on the light curves. In this work, we re-analyzed the one-month time series of the Kepler survey phase to search for solar-like oscillations that might have been missed when using the previous data release. We studied the seismic parameters of 99 stars, among which there are 46 targets with new reported solar-like oscillations, increasing, by around 8%, the known sample of solar-like stars with an asteroseismic analysis of the short-cadence data from this mission. The majority of these stars have mid-to high-resolution spectroscopy publicly available with the LAMOST and APOGEE surveys, respectively, as well as precise Gaia parallaxes. We computed the masses and radii using seismic scaling relations and we find that this new sample features massive stars (above 1.2 M and up to 2 M ) and subgiants. We determined the granulation parameters and amplitude of the modes, which agree with the scaling relations derived for dwarfs and subgiants. The stars studied here are slightly fainter than the previously known sample of main-sequence and subgiants with asteroseismic detections. We also studied the surface rotation and magnetic activity levels of those stars. Our sample of 99 stars has similar levels of activity compared to the previously known sample and is in the same range as the Sun between the minimum and maximum of its activity cycle. We find that for seven stars, a possible blend could be the reason for the non-detection with the early data release. Finally, we compared the radii obtained from the scaling relations with the Gaia ones and we find that the Gaia radii are overestimated by 4.4%, on average, compared to the seismic radii, with a scatter of 12.3% and a decreasing trend according to the evolutionary stage. In addition, for homogeneity purposes, we re-analyzed the DR25 of the main-sequence and subgiant stars with solar-like oscillations that were previously detected and, as a result, we provide the global seismic parameters for a total of 526 stars.

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“…known planet hosts (APOGEE2_TARGET2 bit 11), 2. stars with a confirmed oscillation or granulation signal (APOGEE2_TARGET1 bit 30), 3. red giants that were targeted by the K2 Galactic Archaeology Program (GAP; Stello et al 2017) and not observed with HERMES, 4. GAP targets observed by HERMES (see Wittenmyer et al 2018;Sharma et al 2019;Zinn et al 2020), 5. M dwarfs in the unbiased sample from the Ancillary Science Program described in Appendix B.9 (APO-GEE2_TARGET3 bit 28).…”

Section: Apogee-k2 Surveymentioning

confidence: 99%

Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

Beaton

Oelkers

Hayes

et al. 2021

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The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) “Ancillary Science Programs” competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.

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The K2 Galactic Archaeology Program Data Release 2: Asteroseismic Results from Campaigns 4, 6, and 7

Cited by 39 publications

References 72 publications

The GALAH+ survey: Third data release

The GALAH+ survey: Third data release

Detections of solar-like oscillations in dwarfs and subgiants with Kepler DR25 short-cadence data

Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

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