Constraining the Initial-Final Mass Relation with Wide Double White Dwarfs

TL;DR

This study expands the sample of wide double white dwarf binaries to better constrain the initial-final mass relation, using SDSS data and spectroscopic analysis to identify and characterize new systems.

Contribution

It identifies 65 new wide DWD candidates, increasing the known sample to 142, and reanalyzes the IFMR constraint using a specific DWD system, advancing understanding of white dwarf evolution.

Findings

Discovered 65 new wide DWD candidates in SDSS DR9.

Characterized 32 DA/DA pairs and other WD combinations spectroscopically.

Reanalyzed the IFMR constraint using the DWD PG 0922+162.

Abstract

In wide double white dwarf (DWD) binaries, in which the co-eval WDs evolve independently, the more massive, faster-evolving WD can be used to obtain a main-sequence lifetime for the less-massive WD. By converting this lifetime into an initial mass for the less-massive WD, and combining it with the spectroscopically derived mass for this WD, one can constrain the initial-final mass relation (IFMR). However, the number of known and well-characterized DWDs is small, severely limiting their usefulness for this analysis. To obtain new constraints on the IFMR, we search for wide DWDs in the Sloan Digital Sky Survey (SDSS) Data Release 9. We find 65 new candidate systems, thereby raising the number of known wide DWDs to 142. We then engage in a spectroscopic campaign to characterize these pairs, identifying 32 DA/DA pairs, two DA/DB pairs, four DA/DAH candidate pairs, a previously unidentified candidate triple WD system, and five DA/DC WDs. We present a reanalysis of the constraint on the IFMR placed by Finley & Koester (1997) using the DWD PG 0922+162, and finish by discussing how it could be expanded to a generic set of wide DWDs.