Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

An investigation of non-canonical mixing in red giant stars using APOGEE 12C/13C ratios observed in open cluster stars

Journal Article · · Monthly Notices of the Royal Astronomical Society
 [1];  [1];  [2];  [3];  [4];  [5];  [6];  [7];  [1];  [8];  [9];  [10]
  1. University of Virginia, Charlottesville, VA (United States)
  2. NSF’s National Optical-Infrared Astronomy Research Laboratory, Tucson, AZ (United States); Sorbonne Université, Paris (France)
  3. Herzberg Astronomy and Astrophysics Research Centre, Victoria, BC (Canada)
  4. Sorbonne Université, Paris (France); Observatório Nacional, Rio de Janeiro (Brazil); University of Arizona, Tucson, AZ (United States)
  5. Instituto de Astrofísica de Canarias, Tenerife (Spain); Universidad de La Laguna, Tenerife (Spain)
  6. Max-Planck-Institut für Astrophysik, Garching (Germany)
  7. University of California, Santa Cruz, CA (United States)
  8. Texas Christian University, Fort Worth, TX (United States)
  9. Instituto de Astrofísica de Canarias, Tenerife (Spain)
  10. Universidad de Antofagasta (Chile)
+ Show Author Affiliations

Standard stellar evolution theory poorly predicts the surface abundances of chemical species in low-mass, red giant branch (RGB) stars. Observations show an enhancement of p–p chain and CNO cycle products in red giant envelopes, which suggests the existence of non-canonical mixing that brings interior burning products to the surface of these stars. The 12C/13C ratio is a highly sensitive abundance metric used to probe this mixing. We investigate extra RGB mixing by examining: (1) how 12C/13C is altered along the RGB, and (2) how 12C/13C changes for stars of varying age and mass. Our sample consists of 43 red giants, spread over 15 open clusters from the Sloan Digital Sky Survey’s APOGEE DR17, that have reliable 12C/13C ratios derived from their APOGEE spectra. We vetted these 12C/13C ratios and compared them as a function of evolution and age/mass to the standard mixing model of stellar evolution, and to a model that includes prescriptions for RGB thermohaline mixing and stellar rotation. We find that the observations deviate from standard mixing models, implying the need for extra mixing. Additionally, some of the abundance patterns depart from the thermohaline model, and it is unclear whether these differences are due to incomplete observations, issues inherent to the model, our assumption of the cause of extra mixing, or any combination of these factors. Nevertheless, the surface abundances across our age/mass range clearly deviate from the standard model, agreeing with the notion of a universal mechanism for RGB extra mixing in low-mass stars.

Research Organization:
US Department of Energy (USDOE), Washington, DC (United States). Office of Science, Sloan Digital Sky Survey (SDSS)
Sponsoring Organization:
USDOE
OSTI ID:
2425100
Journal Information:
Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 3 Vol. 524; ISSN 0035-8711
Publisher:
Oxford University PressCopyright Statement
Country of Publication:
United States
Language:
English

References (65)

CNONa and ${^{12}}$C/${^{13}}$C in giant stars of 10 open clusters journal May 2009
Thermohaline instability and rotation-induced mixing journal October 2010
Thermohaline instability and rotation-induced mixing: III. Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars of various metallicities⋆ journal July 2012
The thermohaline, Richardson, Rayleigh-Taylor, Solberg–Høiland, and GSF criteria in rotating stars journal April 2013
The extent of mixing in stellar interiors: the open clusters Collinder 261 and Melotte 66 journal April 2016
TheGaia-ESO Survey: impact of extra mixing on C and N abundances of giant stars journal December 2018
Age determination for 269 Gaia DR2 open clusters journal March 2019
Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era journal January 2020
Painting a portrait of the Galactic disc with its stellar clusters journal July 2020
Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members journal May 2021
New catalogue of optically visible open clusters and candidates journal July 2002
Rotational mixing in low-mass stars journal February 2003
Rotational mixing in low-mass stars journal June 2006
Thermohaline mixing: a physical mechanism governing the photospheric composition of low-mass giants journal March 2007
A grid of MARCS model atmospheres for late-type stars: I. Methods and general properties journal May 2008
Thermohaline Convection in Stellar Interiors. journal February 1972
Meridional circulation and CNO anomalies in red giant stars journal April 1979
Carbon isotope ratios in field Population II giant stars journal December 1986
Carbon isotope ratios and lithium abundances in open cluster giants journal December 1989
Hot bottom burning in asymptotic giant branch stars and its effect on oxygen isotopic abundances journal March 1995
Creation of 7 Li and Destruction of 3 He, 9 Be, 10 B, and 11 B in Low‐Mass Red Giants, Due to Deep Circulation journal January 1999
The CNO Isotopes: Deep Circulation in Red Giants and First and Second Dredge‐up journal January 1999
Deep Circulation in Red Giant Stars: A Solution to the Carbon and Oxygen Isotope Puzzles? journal July 1995
A Consistent Explanation for [TSUP]12[/TSUP]C/[TSUP]13[/TSUP]C, [TSUP]7[/TSUP]Li, and [TSUP]3[/TSUP]He Anomalies in Red Giant Stars journal November 1995
Abundance Anomalies and Rotational Evolution of Low‐Mass Red Giants: A Maximal Mixing Approach journal September 2005
A Spectroscopic Study of the Ancient Milky Way: F‐ and G‐Type Stars in the Third Data Release of the Sloan Digital Sky Survey journal January 2006
The 2.5 m Telescope of the Sloan Digital Sky Survey journal April 2006
Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms? journal December 2007
Target Selection for the Apache Point Observatory Galactic Evolution Experiment (Apogee) journal August 2013
Abundances, Stellar Parameters, and Spectra from the Sdss-Iii/Apogee Survey journal October 2015
The data Reduction Pipeline for the Apache Point Observatory Galactic Evolution Experiment journal November 2015
Magneto-Thermohaline Mixing in red Giants journal April 2009
Numerical Simulations of Thermohaline Convection: Implications for Extra-Mixing in Low-Mass rgb Stars journal October 2010
Modules for Experiments in Stellar Astrophysics (Mesa) journal December 2010
Modules for Experiments in Stellar Astrophysics (Mesa): Planets, Oscillations, Rotation, and Massive Stars journal August 2013
Modules for Experiments in Stellar Astrophysics (Mesa): Binaries, Pulsations, and Explosions journal September 2015
THE SDSS-III APOGEE SPECTRAL LINE LIST FOR H -BAND SPECTROSCOPY journal November 2015
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs journal March 2019
Thermohaline Mixing: does it Really Govern the Atmospheric Chemical Composition of Low-Mass red Giants? journal December 2010
Numerically Determined Transport laws for Fingering (“Thermohaline”) Convection in Astrophysics journal January 2011
The open Cluster Chemical Analysis and Mapping Survey: Local Galactic Metallicity Gradient with Apogee Using sdss dr10 journal October 2013
Red clump stars of the Milky Way – laboratories of extra-mixing journal January 2013
12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791 journal November 2017
Photospheric nitrogen abundances and carbon 12C/13C ratios of red giant stars journal November 2019
C, N and O abundances in red clump stars of the Milky Way journal September 2010
The NMSU 1 m Telescope at Apache Point Observatory journal January 2010
The Optical Design of the 40-in Telescope and of the Irenee DuPont Telescope at Las Campanas Observatory, Chile journal January 1973
The “Salt-Fountain” and Thermohaline Convection journal January 1960
Aspcap: the Apogee Stellar Parameter and Chemical Abundances Pipeline journal May 2016
Mesa Isochrones and Stellar Tracks (Mist). i. Solar-Scaled Models journal May 2016
Mesa Isochrones and Stellar Tracks (Mist) 0: Methods for the Construction of Stellar Isochrones journal January 2016
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe journal June 2017
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) journal August 2017
Target Selection for the SDSS-IV APOGEE-2 Survey journal October 2017
The Open Cluster Chemical Abundances and Mapping Survey. II. Precision Cluster Abundances for APOGEE Using SDSS DR14 journal September 2018
The Open Cluster Chemical Abundances and Mapping Survey. IV. Abundances for 128 Open Clusters Using SDSS/APOGEE DR16 journal April 2020
APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South journal August 2020
The APOGEE Data Release 16 Spectral Line List journal May 2021
Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey journal December 2021
Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey journal December 2021
The Open Cluster Chemical Abundances and Mapping Survey. VI. Galactic Chemical Gradient Analysis from APOGEE DR17 journal August 2022
The Effect of Rotation on Fingering Convection in Stellar Interiors journal July 2018
Modules for Experiments in Stellar Astrophysics (${\mathtt{M}}{\mathtt{E}}{\mathtt{S}}{\mathtt{A}}$): Convective Boundaries, Element Diffusion, and Massive Star Explosions journal February 2018
The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data journal March 2022
Is Thermohaline Mixing the Full Story? Evidence for Separate Mixing Events near the Red Giant Branch Bump journal August 2022

Similar Records

BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS)
Journal Article · Thu Sep 15 00:00:00 EDT 2022 · The Astrophysical Journal. Supplement Series · OSTI ID:1983316
The Open Cluster Chemical Abundances and Mapping Survey. VII. APOGEE DR17 [C/N]–Age Calibration
Journal Article · Fri Apr 22 00:00:00 EDT 2022 · The Astronomical Journal · OSTI ID:1983161
CHEMICAL ABUNDANCES IN A SAMPLE OF RED GIANTS IN THE OPEN CLUSTER NGC 2420 FROM APOGEE
Journal Article · Mon Oct 10 00:00:00 EDT 2016 · Astrophysical Journal · OSTI ID:22667355

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astronomy & Astrophysics
convection
instabilities
open clusters and associations: general
stars: abundances
stars: atmospheres
stars: interiors