- We present EVR-CB-001, the discovery of a compact binary with an extremely low-mass (0.21 +/- 0.05M(circle dot)) helium core white dwarf progenitor (pre-He WD) and an unseen low-mass (0.32 +/- 0.06M(circle dot)) helium white dwarf (He WD) companion. He WDs are thought to evolve from the remnant helium-rich core of a main-sequence star stripped during the giant phase by a close companion. Low-mass He WDs are exotic objects (only about 0.2% of WDs are thought to be less than 0.3 M-circle dot), and are expected to be found in compact binaries. Pre-He WDs are even rarer, and occupy the intermediate phase after the core is stripped, but before the star becomes a fully degenerate WD and with a larger radius (approximate to 0.2R(circle dot)) than a typical WD. The primary component of EVR-CB-001 (the pre-He WD) was originally thought to be a hot subdwarf (sdB) star from its blue color and under-luminous magnitude, characteristic of sdBs. The mass, temperature (T-eff = 18,500 +/- 500 K), and surface gravity (log(g) = 4.96 +/- 0.04) solutionsWe present EVR-CB-001, the discovery of a compact binary with an extremely low-mass (0.21 +/- 0.05M(circle dot)) helium core white dwarf progenitor (pre-He WD) and an unseen low-mass (0.32 +/- 0.06M(circle dot)) helium white dwarf (He WD) companion. He WDs are thought to evolve from the remnant helium-rich core of a main-sequence star stripped during the giant phase by a close companion. Low-mass He WDs are exotic objects (only about 0.2% of WDs are thought to be less than 0.3 M-circle dot), and are expected to be found in compact binaries. Pre-He WDs are even rarer, and occupy the intermediate phase after the core is stripped, but before the star becomes a fully degenerate WD and with a larger radius (approximate to 0.2R(circle dot)) than a typical WD. The primary component of EVR-CB-001 (the pre-He WD) was originally thought to be a hot subdwarf (sdB) star from its blue color and under-luminous magnitude, characteristic of sdBs. The mass, temperature (T-eff = 18,500 +/- 500 K), and surface gravity (log(g) = 4.96 +/- 0.04) solutions from this work are lower than values for typical hot subdwarfs. The primary is likely to be a post-red-giant branch, pre-He WD contracting into a He WD, and at a stage that places it nearest to sdBs on color-magnitude and T-eff-log(g) diagrams. EVR-CB-001 is expected to evolve into a fully double degenerate, compact system that should spin down and potentially evolve into a single hot subdwarf star. Single hot subdwarfs are observed, but progenitor systems have been elusive.…
MetadatenAuthor details: | Jeffrey K. RatzloffORCiD, Brad N. BarlowORCiD, Thomas KupferORCiD, Kyle A. CorcoranORCiD, Stephan Alfred GeierORCiDGND, Evan BauerORCiD, Henry T. Corbett, Ward S. HowardORCiD, Amy GlazierORCiD, Nicholas M. Law |
---|
DOI: | https://doi.org/10.3847/1538-4357/ab3727 |
---|
ISSN: | 0004-637X |
---|
ISSN: | 1538-4357 |
---|
Title of parent work (English): | The astrophysical journal : an international review of spectroscopy and astronomical physics |
---|
Publisher: | IOP Publ. Ltd. |
---|
Place of publishing: | Bristol |
---|
Publication type: | Article |
---|
Language: | English |
---|
Date of first publication: | 2019/09/19 |
---|
Publication year: | 2019 |
---|
Release date: | 2020/11/05 |
---|
Volume: | 883 |
---|
Issue: | 1 |
---|
Number of pages: | 12 |
---|
Funding institution: | NSF CAREER grantNational Science Foundation (NSF)NSF - Office of the Director (OD) [AST-1555175]; Research Corporation Scialog [23782, 23822]; NSFGRFNational Science Foundation (NSF) [DGE-1144081]; NSFNational Science Foundation (NSF) [AST-1812874]; NSF/ATINational Science Foundation (NSF)NSF - Directorate for Mathematical & Physical Sciences (MPS) [AST-1407589]; National Science FoundationNational Science Foundation (NSF) [PHY 17-148958]; Materials Research Science and Engineering Center (MRSEC) at UC Santa Barbara [NSF DMR 1720256, NSF CNS 1725797]; California NanoSystems Institute at UC Santa Barbara [NSF DMR 1720256, NSF CNS 1725797] |
---|
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
---|
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
---|
Peer review: | Referiert |
---|
Publishing method: | Open Access |
---|
| Open Access / Green Open-Access |
---|