Searching for strange quark matter objects among white dwarfs

Kuerban, Abudushataer; Huang, Yun‐Feng; Geng, Jin-Jun; Zong, Hong-Shi

doi:10.1016/j.physletb.2022.137204

Cited by 11 publications

(12 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Figure 4, we present the mass-radius relations of white dwarfs under various constraints on their matter contents. Typical white dwarfs with M > 0.5M ⊙ (Bond et al, 2017) and seven ultra-lowmass and small-radius white dwarfs are indicated by the dots with the corresponding error bars (Kurban et al, 2022). It is evident that the typical white dwarfs are made of light elements with A ≤ 28, where the mass and radius could become slightly larger if lighter elements ( 12 C, 4 He, and 1 H), magnetic field, and temperature effects are accounted for.…”

Section: Resultsmentioning

confidence: 99%

“…To resolve this, it was suggested that the lowmass and small-radius white dwarfs are made of exotic matter such as SQM or udQM. As illustrated by Kurban et al (2022), a strange dwarf with a mass similar to that of a normal white dwarf could harbor an extremely dense SQM core, resulting in a smaller radius that coincides with that of the seven white dwarfs. For absolute stable SQM or udQM with sufficiently small surface tension, it was shown that strangelets or udQM nuggets of a certain size can be more stable than others (Heiselberg, 1993); consequently, the…”

Section: Resultsmentioning

confidence: 99%

“…Mass-radius relations of white dwarfs obtained with the EOSs in Figure 2. The dots with M >0.5M ⊙ represent four typical white dwarfs, namely, Sirius B, Stein 2051 B, Procyon B, and 40 Eri B (Bond et al, 2017), while the seven dots below correspond to the ultra-low-mass and small-radius white dwarfs, namely, LSPM J0815 + 1633, LP 240-30, BD+20 5125B, LP 462-12, WD J1257 + 5428, 2MASS J13453297 + 4200437, and SDSS J085557.46 + 053524.5 (Kurban et al, 2022).…”

Section: Figurementioning

confidence: 99%

“…The surface gravity of a white dwarf can also be measured according to the gravitational redshift of the spectrum lines from the atmosphere (Fontaine et al, 2001;Gentile Fusillo et al, 2018;Chandra et al, 2020), which can be used to fix the mass with additional information on its radius. Throughout the available data on the masses and radii of white dwarfs in the Montreal White Dwarf Database (MWDD; Dufour et al, 2017), as indicated in Table 1, seven ultra-low-mass and small-radius white dwarfs have been identified with masses ranging from ∼0.02 M ⊙ to ∼0.08 M ⊙ and radii ranging from ∼ 4,270 km to 10,670 km (Kurban et al, 2022), which deviate from the M-R relation of typical white dwarfs. It should be noted that no spectral lines have been identified in those stars, and the surface gravity needs to be inferred theoretically (Blouin et al, 2019), which results in large uncertainties.…”

mentioning

confidence: 99%

“…To understand the physical origin of such low-mass and small-radius white dwarfs, possible candidates made of various exotic materials were considered. For example, Kurban et al (2022) proposed that they are, in fact, strange dwarfs comprised of a strange quark matter (SQM) core and a thick normal matter crust (Glendenning et al, 1995). It was suggested that the intermittent fractional collapses of the crust induced by the refilling of materials accreted from its low-mass companion lead to repeating fast radio bursts (Geng et al, 2021).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Ultra-low-mass and small-radius white dwarfs made of heavy elements

Xia,

Huang,

et al. 2023

Front. Astron. Space Sci.

Self Cite

View full text Add to dashboard Cite

Seven possible ultra-low-mass and small-radius white dwarfs have been recently identified, with masses ranging from ∼0.02 M⊙ to ∼0.08 M⊙ and radii ranging from ∼ 4,270 km to 10670 km. The mass–radius measurements of these white dwarfs pose challenges to traditional white dwarf models, assuming they are mostly made of nuclei lighter than 56Fe. In this work, we consider the possibility that those white dwarfs are made of heavier elements. Due to the small charge-to-mass ratios in heavy elements, the electron number density in white dwarf matter is effectively reduced, which reduces the pressure with additional contributions of lattice energy and electron polarization corrections. This consequently leads to white dwarfs with much smaller masses and radii, which coincide with the seven ultra-low-mass and small-radius white dwarfs. The mass of the most massive white dwarfs is effectively reduced and could possibly account for the sub-Chandrasekhar progenitors in underluminous Type Ia supernovae. The corresponding equation of state and matter contents of dense stellar matter with and without reaching the cold-catalyzed ground state are presented, which are obtained using the latest Atomic Mass Evaluation (AME 2020). Further observations are necessary to unveil the actual matter contents in those white dwarfs via, e.g., spectroscopy, asteroseismology, and the discoveries of other ultra-low-mass and small-radius white dwarfs.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Ultra-low-mass and small-radius white dwarfs made of heavy elements

Xia,

Huang,

et al. 2023

Front. Astron. Space Sci.

Self Cite

View full text Add to dashboard Cite

show abstract

Stability and instability of strange dwarfs

Di Clemente,

Drago,

Char

et al. 2023

A&A

View full text Add to dashboard Cite

Aims. More than 20 years ago, the existence of stable white dwarfs with a core of strange quark matter was proposed. More recently, via the study of radial modes, it has been concluded instead that such objects are unstable. We aim to clarify this issue. Methods. We investigated the stability of these objects by looking at their radial oscillations while incorporating boundary conditions at the quark–hadron interface, which correspond to either a rapid or a slow conversion of hadrons into quarks. Results. Our analysis shows that objects of this type are stable if the star is not strongly perturbed and ordinary matter cannot transform into strange quark matter because of the Coulomb barrier separating the two components. On the other hand, ordinary matter can be transformed into strange quark matter if the star undergoes a violent process, as in the preliminary stages of a type Ia supernova, and this causes the system to become unstable and collapse into a strange quark star. In this way, the accretion-induced collapse of strange dwarfs can be facilitated, and kilometre-sized objects with sub-solar masses can be produced.

show abstract