Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars

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Variability in the Massive Open Cluster NGC 1817 from K2 : A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars. / Sandquist, Eric L.; Stello, Dennis; Arentoft, Torben; Brogaard, Karsten; Grundahl, Frank; Vanderburg, Andrew; Hedlund, Anne; Dewitt, Ryan; Ackerman, Taylor R.; Aguilar, Miguel; Buckner, Andrew J.; Juarez, Christian; Ortiz, Arturo J.; Richarte, David; Rivera, Daniel I.; Schlapfer, Levi.

In: Astronomical Journal, Vol. 159, No. 3, 96, 03.2020.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Harvard

Sandquist, EL, Stello, D, Arentoft, T, Brogaard, K, Grundahl, F, Vanderburg, A, Hedlund, A, Dewitt, R, Ackerman, TR, Aguilar, M, Buckner, AJ, Juarez, C, Ortiz, AJ, Richarte, D, Rivera, DI & Schlapfer, L 2020, 'Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars', Astronomical Journal, vol. 159, no. 3, 96. https://doi.org/10.3847/1538-3881/ab68df

APA

Sandquist, E. L., Stello, D., Arentoft, T., Brogaard, K., Grundahl, F., Vanderburg, A., Hedlund, A., Dewitt, R., Ackerman, T. R., Aguilar, M., Buckner, A. J., Juarez, C., Ortiz, A. J., Richarte, D., Rivera, D. I., & Schlapfer, L. (2020). Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars. Astronomical Journal, 159(3), [96]. https://doi.org/10.3847/1538-3881/ab68df

CBE

Sandquist EL, Stello D, Arentoft T, Brogaard K, Grundahl F, Vanderburg A, Hedlund A, Dewitt R, Ackerman TR, Aguilar M, Buckner AJ, Juarez C, Ortiz AJ, Richarte D, Rivera DI, Schlapfer L. 2020. Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars. Astronomical Journal. 159(3):Article 96. https://doi.org/10.3847/1538-3881/ab68df

MLA

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Author

Sandquist, Eric L. ; Stello, Dennis ; Arentoft, Torben ; Brogaard, Karsten ; Grundahl, Frank ; Vanderburg, Andrew ; Hedlund, Anne ; Dewitt, Ryan ; Ackerman, Taylor R. ; Aguilar, Miguel ; Buckner, Andrew J. ; Juarez, Christian ; Ortiz, Arturo J. ; Richarte, David ; Rivera, Daniel I. ; Schlapfer, Levi. / Variability in the Massive Open Cluster NGC 1817 from K2 : A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars. In: Astronomical Journal. 2020 ; Vol. 159, No. 3.

Bibtex

@article{eb8b84ac1d7d4d5fa580f6b4c5fd430b,
title = "Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars",
abstract = "We present a survey of variable stars detected in K2 Campaign 13 within the massive intermediate-age (∼1 Gyr) open cluster NGC 1817. We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities (ν max and/or Δν) for 29 of them. Five stars showed suppressed dipole modes, and the occurrence rates indicate that mode suppression is unaffected by evolution through core helium burning. A subset of the giants in NGC 1817 (and in the similarly aged cluster NGC 6811) have ν max and Δν values at or near the maximum observed for core helium-burning stars, indicating they have core masses near the minimum for fully nondegenerate helium ignition. Further asteroseismic study of these stars can constrain the minimum helium core mass in red clump stars and the physics that determines this limit. Two giant stars show photometric variations on timescales similar to previously measured spectroscopic orbits. Thirteen systems in the field show eclipses, but only five are probable cluster members. We identify 32 δ Sct pulsators, 27 γ Dor candidates, and 7 hybrids that are probable cluster members, with most being new detections. We used the ensemble properties of the δ Sct stars to identify stars with possible radial pulsation modes. Among the oddities we have uncovered are: an eccentric orbit for a short-period binary containing a δ Sct pulsating star; a rare subgiant within the Hertzsprung gap showing δ Sct pulsations; and two hot γ Dor pulsating star candidates.",
author = "Sandquist, {Eric L.} and Dennis Stello and Torben Arentoft and Karsten Brogaard and Frank Grundahl and Andrew Vanderburg and Anne Hedlund and Ryan Dewitt and Ackerman, {Taylor R.} and Miguel Aguilar and Buckner, {Andrew J.} and Christian Juarez and Ortiz, {Arturo J.} and David Richarte and Rivera, {Daniel I.} and Levi Schlapfer",
year = "2020",
month = mar,
doi = "10.3847/1538-3881/ab68df",
language = "English",
volume = "159",
journal = "The Astronomical Journal",
issn = "0004-6256",
publisher = "Institute of Physics Publishing, Inc",
number = "3",

}

RIS

TY - JOUR

T1 - Variability in the Massive Open Cluster NGC 1817 from K2

T2 - A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars

AU - Sandquist, Eric L.

AU - Stello, Dennis

AU - Arentoft, Torben

AU - Brogaard, Karsten

AU - Grundahl, Frank

AU - Vanderburg, Andrew

AU - Hedlund, Anne

AU - Dewitt, Ryan

AU - Ackerman, Taylor R.

AU - Aguilar, Miguel

AU - Buckner, Andrew J.

AU - Juarez, Christian

AU - Ortiz, Arturo J.

AU - Richarte, David

AU - Rivera, Daniel I.

AU - Schlapfer, Levi

PY - 2020/3

Y1 - 2020/3

N2 - We present a survey of variable stars detected in K2 Campaign 13 within the massive intermediate-age (∼1 Gyr) open cluster NGC 1817. We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities (ν max and/or Δν) for 29 of them. Five stars showed suppressed dipole modes, and the occurrence rates indicate that mode suppression is unaffected by evolution through core helium burning. A subset of the giants in NGC 1817 (and in the similarly aged cluster NGC 6811) have ν max and Δν values at or near the maximum observed for core helium-burning stars, indicating they have core masses near the minimum for fully nondegenerate helium ignition. Further asteroseismic study of these stars can constrain the minimum helium core mass in red clump stars and the physics that determines this limit. Two giant stars show photometric variations on timescales similar to previously measured spectroscopic orbits. Thirteen systems in the field show eclipses, but only five are probable cluster members. We identify 32 δ Sct pulsators, 27 γ Dor candidates, and 7 hybrids that are probable cluster members, with most being new detections. We used the ensemble properties of the δ Sct stars to identify stars with possible radial pulsation modes. Among the oddities we have uncovered are: an eccentric orbit for a short-period binary containing a δ Sct pulsating star; a rare subgiant within the Hertzsprung gap showing δ Sct pulsations; and two hot γ Dor pulsating star candidates.

AB - We present a survey of variable stars detected in K2 Campaign 13 within the massive intermediate-age (∼1 Gyr) open cluster NGC 1817. We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities (ν max and/or Δν) for 29 of them. Five stars showed suppressed dipole modes, and the occurrence rates indicate that mode suppression is unaffected by evolution through core helium burning. A subset of the giants in NGC 1817 (and in the similarly aged cluster NGC 6811) have ν max and Δν values at or near the maximum observed for core helium-burning stars, indicating they have core masses near the minimum for fully nondegenerate helium ignition. Further asteroseismic study of these stars can constrain the minimum helium core mass in red clump stars and the physics that determines this limit. Two giant stars show photometric variations on timescales similar to previously measured spectroscopic orbits. Thirteen systems in the field show eclipses, but only five are probable cluster members. We identify 32 δ Sct pulsators, 27 γ Dor candidates, and 7 hybrids that are probable cluster members, with most being new detections. We used the ensemble properties of the δ Sct stars to identify stars with possible radial pulsation modes. Among the oddities we have uncovered are: an eccentric orbit for a short-period binary containing a δ Sct pulsating star; a rare subgiant within the Hertzsprung gap showing δ Sct pulsations; and two hot γ Dor pulsating star candidates.

UR - http://www.scopus.com/inward/record.url?scp=85086563009&partnerID=8YFLogxK

U2 - 10.3847/1538-3881/ab68df

DO - 10.3847/1538-3881/ab68df

M3 - Journal article

C2 - 32095021

AN - SCOPUS:85086563009

VL - 159

JO - The Astronomical Journal

JF - The Astronomical Journal

SN - 0004-6256

IS - 3

M1 - 96

ER -