The Ultramassive White Dwarfs of the Alpha Persei Cluster

Miller, David R.; Caiazzo, Ilaria; Heyl, Jeremy; Richer, Harvey

doi:10.48550/arxiv.2110.09668

Cited by 3 publications

(6 citation statements)

References 27 publications

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“…Therefore, the core-chemical composition of an ultra-massive WD is crucial when determining its mass and its cooling times using log g and T eff measurements. Assuming erroneously that an ultra-massive WD has CO-chemical composition, would lead to an o v erestimation MNRAS 511, 5198-5206 (2022) 2004), Nitta et al ( 2016 ), Gianninas et al ( 2011 ), Kleinman et al ( 2013 ), Bours et al ( 2015 ), Kepler et al ( 2016 ), Curd et al ( 2017), Hollands et al ( 2020), and Miller et al ( 2021.…”

Section: The Ultra-massi V E Wd Cooling Timesmentioning

confidence: 99%

The evolution of ultra-massive carbon–oxygen white dwarfs

Camisassa

Althaus

Koester

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Ultra-massive white dwarfs ($\rm M_{WD} \gtrsim 1.05\, {\rm M}_{\odot }$) are considered powerful tools to study type Ia supernovae explosions, merger events, the occurrence of physical processes in the Super Asymptotic Giant Branch (SAGB) phase, and the existence of high magnetic fields. Traditionally, ultra-massive white dwarfs are expected to harbour oxygen-neon (ONe) cores. However, new observations and recent theoretical studies suggest that the progenitors of some ultra-massive white dwarfs can avoid carbon burning, leading to the formation of ultra-massive white dwarfs harbouring carbon-oxygen (CO) cores. Here we present a set of ultra-massive white dwarf evolutionary sequences with CO cores for a wide range of metallicity and masses. We take into account the energy released by latent heat and phase separation during the crystallization process and by 22Ne sedimentation. Realistic chemical profiles resulting from the full computation of progenitor evolution are considered. We compare our CO ultra-massive white dwarf models with ONe models. We conclude that CO ultra-massive white dwarfs evolve significantly slower than their ONe counterparts mainly for three reasons: their larger thermal content, the effect of crystallization, and the effect of 22Ne sedimentation. We also provide colors in several photometric bands on the basis of new model atmospheres. These CO ultra-massive white dwarf models, together with the ONe ultra-massive white dwarf models, provide an appropriate theoretical framework to study the ultra-massive white dwarf population in our Galaxy.

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Section: The Ultra-massi V E Wd Cooling Timesmentioning

confidence: 99%

The evolution of ultra-massive carbon–oxygen white dwarfs

Camisassa

Althaus

Koester

et al. 2022

Monthly Notices of the Royal Astronomical Society

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“…By contrast, in green, we indicate the locations of six bright blue stars near the tip of the main sequence. These stars are significantly more centrally concentrated toward the cluster core than the WDs, suggesting that the WDs are either nonmembers, are too faint to be found in the crowded cluster core, or have been ejected from the central regions of the cluster (Heyl et al 2021(Heyl et al , 2022Miller et al 2021). This latter scenario is unlikely, however, given the extremely short cooling times of these very hot WDs.…”

Section: Ngc 2164mentioning

confidence: 99%

“…To probe this limit, we have been searching for massive WDs that are members of young open star clusters (Richer et al 2019(Richer et al , 2021Caiazzo et al 2020;Heyl et al 2021Heyl et al , 2022Miller et al 2021). Identifying massive WDs in young clusters is a requirement as it allows us to use the WD cooling age together with the cluster age to estimate the WD's progenitor mass.…”

Section: Introductionmentioning

confidence: 99%

“…Open clusters are in fact known to be deficient in WDs (Fellhauer et al 2003), and this deficit is thought to occur from WDs receiving a natal velocity kick of about 1 km s −1 at birth (see Heyl 2007;Fregeau et al 2009;El-Badry & Rix 2018, and references therein). In order to increase the number of potential massive WD cluster members, we expanded our search to include WDs that may have escaped from their host clusters (Heyl et al 2022;Miller et al 2021).…”

Section: Introductionmentioning

confidence: 99%

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When Do Stars Go Boom?

Richer

Cohen

Correnti

et al. 2022

ApJL

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The maximum mass of a star that can produce a white dwarf (WD) is an important astrophysical quantity. One of the best approaches to establishing this limit is to search for WDs in young star clusters in which only massive stars have had time to evolve and where the mass of the progenitor can be established from the cooling time of the WD together with the age of the cluster. Searches in young Milky Way clusters have not thus far yielded WD members more massive than about 1.1 M ⊙, well below the Chandrasekhar mass of 1.38 M ⊙, nor progenitors with masses in excess of about 6 M ⊙. However, the hunt for potentially massive WDs that escaped their cluster environs is yielding interesting candidates. To expand the cluster sample further, we used HST to survey four young and massive star clusters in the Magellanic Clouds for bright WDs that could have evolved from stars as massive as 10 M ⊙. We located five potential WD candidates in the oldest of the four clusters examined, the first extragalactic single WDs thus far discovered. As these hot WDs are very faint at optical wavelengths, final confirmation will likely have to await spectroscopy with 30 m class telescopes.

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“…These stars play a key role in ★ The cooling sequences are publicly available for download at http://evolgroup.fcaglp.unlp.edu.ar/TRACKS/tracks.html † E-mail: maria.camisassa@colorado.edu our understanding of type Ia Supernova explosions, the occurrence of physical processes in the asymptotic giant-branch (AGB) phase, the existence of high-field magnetic white dwarfs, and the occurrence of double white dwarf mergers (Dunlap & Clemens 2015;Reindl et al 2020). The observation of ultra-massive white dwarfs has been reported in several studies in the literature (Mukadam et al 2004;Nitta et al 2016;Gianninas et al 2011;Kleinman et al 2013;Bours et al 2015;Kepler et al 2016;Curd et al 2017;Kilic et al 2021;Hollands et al 2020;Caiazzo et al 2021;Miller et al 2021).…”

Section: Introductionmentioning

confidence: 99%

The evolution of ultra-massive carbon oxygen white dwarfs

Camisassa,

Althaus,

Koester

et al. 2022

Preprint

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Ultra-massive white dwarfs (M WD 1.05 M ⊙ ) are considered powerful tools to study type Ia supernovae explosions, merger events, the occurrence of physical processes in the Super Asymptotic Giant Branch (SAGB) phase, and the existence of high magnetic fields. Traditionally, ultra-massive white dwarfs are expected to harbour oxygen-neon (ONe) cores. However, new observations and recent theoretical studies suggest that the progenitors of some ultramassive white dwarfs can avoid carbon burning, leading to the formation of ultra-massive white dwarfs harbouring carbon-oxygen (CO) cores. Here we present a set of ultra-massive white dwarf evolutionary sequences with CO cores for a wide range of metallicity and masses. We take into account the energy released by latent heat and phase separation during the crystallization process and by 22 Ne sedimentation. Realistic chemical profiles resulting from the full computation of progenitor evolution are considered. We compare our CO ultra-massive white dwarf models with ONe models. We conclude that CO ultra-massive white dwarfs evolve significantly slower than their ONe counterparts mainly for three reasons: their larger thermal content, the effect of crystallization, and the effect of 22 Ne sedimentation. We also provide colors in several photometric bands on the basis of new model atmospheres. These CO ultramassive white dwarf models, together with the ONe ultra-massive white dwarf models, provide an appropriate theoretical framework to study the ultra-massive white dwarf population in our Galaxy.

show abstract

The Ultramassive White Dwarfs of the Alpha Persei Cluster

Cited by 3 publications

References 27 publications

The evolution of ultra-massive carbon–oxygen white dwarfs

The evolution of ultra-massive carbon–oxygen white dwarfs

When Do Stars Go Boom?

The evolution of ultra-massive carbon oxygen white dwarfs

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