# The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc

Research output: Contribution to journalArticle

## Standard

The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc. / Rendle, B. M.; Miglio, A.; Chiappini, C.; Valentini, M.; Davies, G. R.; Mosser, B.; Elsworth, Y.; García, R. A.; Mathur, S.; Jofré, P.; Worley, C. C.; Casagrande, L.; Girardi, L.; Lund, M. N.; Feuillet, D. K.; Gavel, A.; Magrini, L.; Khan, S.; Rodrigues, T. S.; Johnson, J. A.; Cunha, K.; Lane, R. L.; Nitschelm, C.; Chaplin, W. J.

In: Monthly Notices of the Royal Astronomical Society, Vol. 490, No. 4, 04.11.2019.

Research output: Contribution to journalArticle

## Harvard

Rendle, BM, Miglio, A, Chiappini, C, Valentini, M, Davies, GR, Mosser, B, Elsworth, Y, García, RA, Mathur, S, Jofré, P, Worley, CC, Casagrande, L, Girardi, L, Lund, MN, Feuillet, DK, Gavel, A, Magrini, L, Khan, S, Rodrigues, TS, Johnson, JA, Cunha, K, Lane, RL, Nitschelm, C & Chaplin, WJ 2019, 'The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc', Monthly Notices of the Royal Astronomical Society, vol. 490, no. 4. https://doi.org/10.1093/mnras/stz2454

## APA

Rendle, B. M., Miglio, A., Chiappini, C., Valentini, M., Davies, G. R., Mosser, B., Elsworth, Y., García, R. A., Mathur, S., Jofré, P., Worley, C. C., Casagrande, L., Girardi, L., Lund, M. N., Feuillet, D. K., Gavel, A., Magrini, L., Khan, S., Rodrigues, T. S., ... Chaplin, W. J. (2019). The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc. Monthly Notices of the Royal Astronomical Society, 490(4). https://doi.org/10.1093/mnras/stz2454

## Author

Rendle, B. M. ; Miglio, A. ; Chiappini, C. ; Valentini, M. ; Davies, G. R. ; Mosser, B. ; Elsworth, Y. ; García, R. A. ; Mathur, S. ; Jofré, P. ; Worley, C. C. ; Casagrande, L. ; Girardi, L. ; Lund, M. N. ; Feuillet, D. K. ; Gavel, A. ; Magrini, L. ; Khan, S. ; Rodrigues, T. S. ; Johnson, J. A. ; Cunha, K. ; Lane, R. L. ; Nitschelm, C. ; Chaplin, W. J. / The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc. In: Monthly Notices of the Royal Astronomical Society. 2019 ; Vol. 490, No. 4.

## Bibtex

@article{427a9863a16a46e5a07ac9e62d3f8d3a,
title = "The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc",
abstract = " Analyses of data from spectroscopic and astrometric surveys have led to conflicting results concerning the vertical characteristics of the Milky Way. Ages are often used to provide clarity, but typical uncertainties of $>$ 40\,\% restrict the validity of the inferences made. Using the \textit{Kepler} APOKASC sample for context, we explore the global population trends of two K2 campaign fields (3 and 6), which extend further vertically out of the Galactic plane than APOKASC. We analyse the properties of red giant stars utilising three asteroseismic data analysis methods to cross-check and validate detections. The Bayesian inference tool PARAM is used to determine the stellar masses, radii and ages. Evidence of a pronounced red giant branch bump and an [$\alpha$/Fe] dependence on the position of the red clump is observed from the radii distribution of the K2 fields. Two peaks in the age distribution centred at $\sim$5 and and $\sim$12 Gyr are found using a sample with $\sigma_{\rm{age}}$ $$0.1) [\alpha/Fe] stars. As a function of vertical distance from the Galactic mid-plane (|Z|), the age distribution shows a transition from a young to old stellar population with increasing |Z| for the K2 fields. Further coverage of campaign targets with high resolution spectroscopy is required to increase the yield of precise ages achievable with asteroseismology. ", keywords = "astro-ph.SR, astro-ph.GA", author = "Rendle, {B. M.} and A. Miglio and C. Chiappini and M. Valentini and Davies, {G. R.} and B. Mosser and Y. Elsworth and Garc{\'i}a, {R. A.} and S. Mathur and P. Jofr{\'e} and Worley, {C. C.} and L. Casagrande and L. Girardi and Lund, {M. N.} and Feuillet, {D. K.} and A. Gavel and L. Magrini and S. Khan and Rodrigues, {T. S.} and Johnson, {J. A.} and K. Cunha and Lane, {R. L.} and C. Nitschelm and Chaplin, {W. J.}", note = "17 pages, 16 figures. Accepted to MNRAS 01/08/2019. Updated manuscript", year = "2019", month = nov day = "4", doi = "10.1093/mnras/stz2454", language = "English", volume = "490", journal = "Monthly Notices of the Royal Astronomical Society", issn = "0035-8711", publisher = "SIPRI/Oxford University Press", number = "4", } ## RIS TY - JOUR T1 - The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc AU - Rendle, B. M. AU - Miglio, A. AU - Chiappini, C. AU - Valentini, M. AU - Davies, G. R. AU - Mosser, B. AU - Elsworth, Y. AU - García, R. A. AU - Mathur, S. AU - Jofré, P. AU - Worley, C. C. AU - Casagrande, L. AU - Girardi, L. AU - Lund, M. N. AU - Feuillet, D. K. AU - Gavel, A. AU - Magrini, L. AU - Khan, S. AU - Rodrigues, T. S. AU - Johnson, J. A. AU - Cunha, K. AU - Lane, R. L. AU - Nitschelm, C. AU - Chaplin, W. J. N1 - 17 pages, 16 figures. Accepted to MNRAS 01/08/2019. Updated manuscript PY - 2019/11/4 Y1 - 2019/11/4 N2 - Analyses of data from spectroscopic and astrometric surveys have led to conflicting results concerning the vertical characteristics of the Milky Way. Ages are often used to provide clarity, but typical uncertainties of > 40\,\% restrict the validity of the inferences made. Using the \textit{Kepler} APOKASC sample for context, we explore the global population trends of two K2 campaign fields (3 and 6), which extend further vertically out of the Galactic plane than APOKASC. We analyse the properties of red giant stars utilising three asteroseismic data analysis methods to cross-check and validate detections. The Bayesian inference tool PARAM is used to determine the stellar masses, radii and ages. Evidence of a pronounced red giant branch bump and an [\alpha/Fe] dependence on the position of the red clump is observed from the radii distribution of the K2 fields. Two peaks in the age distribution centred at \sim5 and and \sim12 Gyr are found using a sample with \sigma_{\rm{age}}$$ 0.1) [$\alpha$/Fe] stars. As a function of vertical distance from the Galactic mid-plane ($|Z|$), the age distribution shows a transition from a young to old stellar population with increasing $|Z|$ for the K2 fields. Further coverage of campaign targets with high resolution spectroscopy is required to increase the yield of precise ages achievable with asteroseismology.

AB - Analyses of data from spectroscopic and astrometric surveys have led to conflicting results concerning the vertical characteristics of the Milky Way. Ages are often used to provide clarity, but typical uncertainties of $>$ 40\,\% restrict the validity of the inferences made. Using the \textit{Kepler} APOKASC sample for context, we explore the global population trends of two K2 campaign fields (3 and 6), which extend further vertically out of the Galactic plane than APOKASC. We analyse the properties of red giant stars utilising three asteroseismic data analysis methods to cross-check and validate detections. The Bayesian inference tool PARAM is used to determine the stellar masses, radii and ages. Evidence of a pronounced red giant branch bump and an [$\alpha$/Fe] dependence on the position of the red clump is observed from the radii distribution of the K2 fields. Two peaks in the age distribution centred at $\sim$5 and and $\sim$12 Gyr are found using a sample with $\sigma_{\rm{age}}$  0.1) [$\alpha$/Fe] stars. As a function of vertical distance from the Galactic mid-plane ($|Z|$), the age distribution shows a transition from a young to old stellar population with increasing $|Z|$ for the K2 fields. Further coverage of campaign targets with high resolution spectroscopy is required to increase the yield of precise ages achievable with asteroseismology.

KW - astro-ph.SR

KW - astro-ph.GA

U2 - 10.1093/mnras/stz2454

DO - 10.1093/mnras/stz2454

M3 - Article

VL - 490

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -