Determining Ages of APOGEE Giants with Known Distances
Feuillet, Diane LU
; Bovy, Jo
; Holtzman, Jon
; Girardi, L.
; MacDonald, Nick
; Majewski, Steven R.
and Nidever, D. L.
(2016)
In The Astrophysical Journal
817(1).
- Abstract
- We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ̃ 22,500), near infrared (1.51-1.7 μm) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [α/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30%. For giants, the relatively rapid evolution up the red giant branch... (More)
- We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ̃ 22,500), near infrared (1.51-1.7 μm) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [α/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30%. For giants, the relatively rapid evolution up the red giant branch allows the age to be constrained by the mass. We examine methods of estimating age using both the mass-age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant SFH. To improve the SFH prior, we use a hierarchical modeling approach to constrain the parameters of the model SFH using the age probability distribution functions of the data. The results of an α-dependent Gaussian SFH model show a clear age-[α/M] relation at all ages. Using this SFH model as the prior for an empirical Bayesian analysis, we determine ages for individual stars. The resulting age-metallicity relation is flat, with a slight decrease in [M/H] at the oldest ages and a ̃0.5 dex spread in metallicity across most ages. For stars with ages ≲1 Gyr we find a smaller spread, consistent with radial migration having a smaller effect on these young stars than on the older stars. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/bac95d0c-02b2-484c-8c12-cb85cd87831e
- author
- Feuillet, Diane
LU
; Bovy, Jo
; Holtzman, Jon
; Girardi, L.
; MacDonald, Nick
; Majewski, Steven R.
and Nidever, D. L.
- publishing date
- 2016-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The Astrophysical Journal
- volume
- 817
- issue
- 1
- pages
- 14 pages
- publisher
- American Astronomical Society
- external identifiers
-
- scopus:84955460363
- ISSN
- 0004-637X
- DOI
- 10.3847/0004-637X/817/1/40
- language
- English
- LU publication?
- no
- id
- bac95d0c-02b2-484c-8c12-cb85cd87831e
- date added to LUP
- 2019-11-27 10:50:51
- date last changed
- 2022-03-28 13:47:02
@article{bac95d0c-02b2-484c-8c12-cb85cd87831e,
abstract = {{We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ̃ 22,500), near infrared (1.51-1.7 μm) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [α/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30%. For giants, the relatively rapid evolution up the red giant branch allows the age to be constrained by the mass. We examine methods of estimating age using both the mass-age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant SFH. To improve the SFH prior, we use a hierarchical modeling approach to constrain the parameters of the model SFH using the age probability distribution functions of the data. The results of an α-dependent Gaussian SFH model show a clear age-[α/M] relation at all ages. Using this SFH model as the prior for an empirical Bayesian analysis, we determine ages for individual stars. The resulting age-metallicity relation is flat, with a slight decrease in [M/H] at the oldest ages and a ̃0.5 dex spread in metallicity across most ages. For stars with ages ≲1 Gyr we find a smaller spread, consistent with radial migration having a smaller effect on these young stars than on the older stars.}},
author = {{Feuillet, Diane and Bovy, Jo and Holtzman, Jon and Girardi, L. and MacDonald, Nick and Majewski, Steven R. and Nidever, D. L.}},
issn = {{0004-637X}},
language = {{eng}},
number = {{1}},
publisher = {{American Astronomical Society}},
series = {{The Astrophysical Journal}},
title = {{Determining Ages of APOGEE Giants with Known Distances}},
url = {{http://dx.doi.org/10.3847/0004-637X/817/1/40}},
doi = {{10.3847/0004-637X/817/1/40}},
volume = {{817}},
year = {{2016}},
}