Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body
The polluted white dwarf (WD) system SDSS J122859.93+104032.9 (SDSS J1228) shows variable emission features interpreted as originating from a solid core fragment held together against tidal forces by its own internal strength, orbiting within its surrounding debris disk. Estimating the size of this...
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| Format: | Article |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acdb69 |
| _version_ | 1797694439430291456 |
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| author | Arianna M. Dwomoh Evan B. Bauer |
| author_facet | Arianna M. Dwomoh Evan B. Bauer |
| author_sort | Arianna M. Dwomoh |
| collection | DOAJ |
| description | The polluted white dwarf (WD) system SDSS J122859.93+104032.9 (SDSS J1228) shows variable emission features interpreted as originating from a solid core fragment held together against tidal forces by its own internal strength, orbiting within its surrounding debris disk. Estimating the size of this orbiting solid body requires modeling the accretion rate of the polluting material that is observed mixing into the WD surface. That material is supplied via sublimation from the surface of the orbiting solid body. The sublimation rate can be estimated as a simple function of the surface area of the solid body and the incident flux from the nearby hot WD. On the other hand, estimating the accretion rate requires detailed modeling of the surface structure and mixing in the accreting WD. In this work, we present MESA WD models for SDSS J1228 that account for the thermohaline instability and mixing in addition to heavy element sedimentation to constrain accurately the sublimation and accretion rate necessary to supply the observed pollution. We derive a total accretion rate of ${\dot{M}}_{\mathrm{acc}}=1.8\times {10}^{11}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ , several orders of magnitude higher than the ${\dot{M}}_{\mathrm{acc}}=5.6\times {10}^{8}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ estimate obtained in earlier efforts. The larger mass accretion rate implies that the minimum estimated radius of the orbiting solid body is ${r}_{\min }$ = 72 km, which, although significantly larger than prior estimates, still lies within the upper bounds (a few hundred kilometers) for which the internal strength could no longer withstand the tidal forces from the gravity of the WD. |
| first_indexed | 2024-03-12T02:57:59Z |
| format | Article |
| id | doaj.art-52fc0f4d3bba4305903d85bee2849e63 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T02:57:59Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-52fc0f4d3bba4305903d85bee2849e632023-09-03T15:07:29ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195229510.3847/1538-4357/acdb69Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid BodyArianna M. Dwomoh0https://orcid.org/0000-0002-0800-7894Evan B. Bauer1https://orcid.org/0000-0002-4791-6724Duke University , 2138 Campus Drive, Durham, NC 27708, USA ; arianna.dwomoh@duke.edu; Center for Astrophysics Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USACenter for Astrophysics Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USAThe polluted white dwarf (WD) system SDSS J122859.93+104032.9 (SDSS J1228) shows variable emission features interpreted as originating from a solid core fragment held together against tidal forces by its own internal strength, orbiting within its surrounding debris disk. Estimating the size of this orbiting solid body requires modeling the accretion rate of the polluting material that is observed mixing into the WD surface. That material is supplied via sublimation from the surface of the orbiting solid body. The sublimation rate can be estimated as a simple function of the surface area of the solid body and the incident flux from the nearby hot WD. On the other hand, estimating the accretion rate requires detailed modeling of the surface structure and mixing in the accreting WD. In this work, we present MESA WD models for SDSS J1228 that account for the thermohaline instability and mixing in addition to heavy element sedimentation to constrain accurately the sublimation and accretion rate necessary to supply the observed pollution. We derive a total accretion rate of ${\dot{M}}_{\mathrm{acc}}=1.8\times {10}^{11}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ , several orders of magnitude higher than the ${\dot{M}}_{\mathrm{acc}}=5.6\times {10}^{8}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ estimate obtained in earlier efforts. The larger mass accretion rate implies that the minimum estimated radius of the orbiting solid body is ${r}_{\min }$ = 72 km, which, although significantly larger than prior estimates, still lies within the upper bounds (a few hundred kilometers) for which the internal strength could no longer withstand the tidal forces from the gravity of the WD.https://doi.org/10.3847/1538-4357/acdb69White dwarf starsStellar accretion disksStellar diffusionPlanetary system evolution |
| spellingShingle | Arianna M. Dwomoh Evan B. Bauer Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body The Astrophysical Journal White dwarf stars Stellar accretion disks Stellar diffusion Planetary system evolution |
| title | Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body |
| title_full | Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body |
| title_fullStr | Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body |
| title_full_unstemmed | Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body |
| title_short | Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body |
| title_sort | reinterpreting the polluted white dwarf sdss j122859 93 104032 9 in light of thermohaline mixing models more polluting material from a larger orbiting solid body |
| topic | White dwarf stars Stellar accretion disks Stellar diffusion Planetary system evolution |
| url | https://doi.org/10.3847/1538-4357/acdb69 |
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