The White Dwarf Cooling Age of the Open Cluster NGC 2420

Ted von Hippel; Gerard Gilmore

The White Dwarf Cooling Age of the Open Cluster NGC 2420

Ted von Hippel, Gerard Gilmore

Physical Sciences

Institute of Astronomy, Cambridge

Research output: Contribution to journal › Article › peer-review

Abstract

We have used deep HST WFPC2 observations of two fields in NGC 2420 to produce a cluster color-magnitude diagram down to V ≈ 27. After imposing morphological selection criteria we find eight candidate white dwarfs in NGC 2420. Our completeness estimates indicate that we have found the terminus of the WD cooling sequence. We argue that the cluster distance modulus is likely to be close to 12.10 with E(B-V) = 0.04. With these parameters we find a white dwarf cooling age for NGC 2420 of 2.0 ± 0.20 (1 σ) Gyr. The 0.20 Gyr uncertainty includes errors in the photometry, sequence fitting, precursor timescales, and theoretical white dwarf cooling timescales. Comparing the cluster white dwarf cooling age to ages derived from stellar isochrone fitting we find a preference for ages derived from models incorporating convective overshoot.

Original language	American English
Journal	The Astronomical Journal
Volume	120
State	Published - Sep 1 2000

Keywords

Galaxy : stellar content
open clusters and associations : individual (NGC 2420)
stars : evolution
white dwarfs

Disciplines

Stars, Interstellar Medium and the Galaxy

Access to Document

The White Dwarf Cooling Age of the Open Cluster NGC 2420Final published version, 426 KBLicense: CC BY

Cite this

@article{8cc1b4f252de4ad3abd0381252b6c816,

title = "The White Dwarf Cooling Age of the Open Cluster NGC 2420",

abstract = " We have used deep HST WFPC2 observations of two fields in NGC 2420 to produce a cluster color-magnitude diagram down to V ≈ 27. After imposing morphological selection criteria we find eight candidate white dwarfs in NGC 2420. Our completeness estimates indicate that we have found the terminus of the WD cooling sequence. We argue that the cluster distance modulus is likely to be close to 12.10 with E(B-V) = 0.04. With these parameters we find a white dwarf cooling age for NGC 2420 of 2.0 ± 0.20 (1 σ) Gyr. The 0.20 Gyr uncertainty includes errors in the photometry, sequence fitting, precursor timescales, and theoretical white dwarf cooling timescales. Comparing the cluster white dwarf cooling age to ages derived from stellar isochrone fitting we find a preference for ages derived from models incorporating convective overshoot.",

keywords = "Galaxy : stellar content, open clusters and associations : individual (NGC 2420), stars : evolution, white dwarfs",

author = "{von Hippel}, Ted and Gerard Gilmore",

year = "2000",

month = sep,

day = "1",

language = "American English",

volume = "120",

journal = "The Astronomical Journal",

}

TY - JOUR

T1 - The White Dwarf Cooling Age of the Open Cluster NGC 2420

AU - von Hippel, Ted

AU - Gilmore, Gerard

PY - 2000/9/1

Y1 - 2000/9/1

N2 - We have used deep HST WFPC2 observations of two fields in NGC 2420 to produce a cluster color-magnitude diagram down to V ≈ 27. After imposing morphological selection criteria we find eight candidate white dwarfs in NGC 2420. Our completeness estimates indicate that we have found the terminus of the WD cooling sequence. We argue that the cluster distance modulus is likely to be close to 12.10 with E(B-V) = 0.04. With these parameters we find a white dwarf cooling age for NGC 2420 of 2.0 ± 0.20 (1 σ) Gyr. The 0.20 Gyr uncertainty includes errors in the photometry, sequence fitting, precursor timescales, and theoretical white dwarf cooling timescales. Comparing the cluster white dwarf cooling age to ages derived from stellar isochrone fitting we find a preference for ages derived from models incorporating convective overshoot.

AB - We have used deep HST WFPC2 observations of two fields in NGC 2420 to produce a cluster color-magnitude diagram down to V ≈ 27. After imposing morphological selection criteria we find eight candidate white dwarfs in NGC 2420. Our completeness estimates indicate that we have found the terminus of the WD cooling sequence. We argue that the cluster distance modulus is likely to be close to 12.10 with E(B-V) = 0.04. With these parameters we find a white dwarf cooling age for NGC 2420 of 2.0 ± 0.20 (1 σ) Gyr. The 0.20 Gyr uncertainty includes errors in the photometry, sequence fitting, precursor timescales, and theoretical white dwarf cooling timescales. Comparing the cluster white dwarf cooling age to ages derived from stellar isochrone fitting we find a preference for ages derived from models incorporating convective overshoot.

KW - Galaxy : stellar content

KW - open clusters and associations : individual (NGC 2420)

KW - stars : evolution

KW - white dwarfs

UR - https://commons.erau.edu/publication/217

M3 - Article

VL - 120

JO - The Astronomical Journal

JF - The Astronomical Journal

ER -

The White Dwarf Cooling Age of the Open Cluster NGC 2420

Abstract

Keywords

Disciplines

Access to Document

Other files and links

Cite this