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Metal Pollution of the Solar White Dwarf by Solar System Small Bodies

Li, Daohai LU orcid ; Mustill, Alexander J. LU orcid and Davies, Melvyn B. LU (2022) In Astrophysical Journal 924(2).
Abstract

White dwarfs (WDs) often show metal lines in their spectra, indicating accretion of asteroidal material. Our Sun is to become a WD in several gigayears. Here, we examine how the solar WD accretes from the three major small body populations: the main belt asteroids (MBAs), Jovian Trojan asteroids (JTAs), and trans-Neptunian objects (TNOs). Owing to the solar mass loss during the giant branch, 40% of the JTAs are lost but the vast majority of MBAs and TNOs survive. During the WD phase, objects from all three populations are sporadically scattered onto the WD, implying ongoing accretion. For young cooling ages ≲100 Myr, accretion of MBAs predominates; our predicted accretion rate ∼106 g s-1 falls short of observations by two orders of... (More)

White dwarfs (WDs) often show metal lines in their spectra, indicating accretion of asteroidal material. Our Sun is to become a WD in several gigayears. Here, we examine how the solar WD accretes from the three major small body populations: the main belt asteroids (MBAs), Jovian Trojan asteroids (JTAs), and trans-Neptunian objects (TNOs). Owing to the solar mass loss during the giant branch, 40% of the JTAs are lost but the vast majority of MBAs and TNOs survive. During the WD phase, objects from all three populations are sporadically scattered onto the WD, implying ongoing accretion. For young cooling ages ≲100 Myr, accretion of MBAs predominates; our predicted accretion rate ∼106 g s-1 falls short of observations by two orders of magnitude. On gigayear timescales, thanks to the consumption of the TNOs that kicks in ⪆100 Myr, the rate oscillates around 106-107 g s-1 until several gigayears and drops to ∼105 g s-1 at 10 Gyr. Our solar WD accretion rate from 1 Gyr and beyond agrees well with those of the extrasolar WDs. We show that for the solar WD, the accretion source region evolves in an inside-out pattern. Moreover, in a realistic small body population with individual sizes covering a wide range as WD pollutants, the accretion is dictated by the largest objects. As a consequence, the accretion rate is lower by an order of magnitude than that from a population of bodies of a uniform size and the same total mass and shows greater scatter.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Astrophysical Journal
volume
924
issue
2
article number
61
publisher
American Astronomical Society
external identifiers
  • scopus:85123522936
ISSN
0004-637X
DOI
10.3847/1538-4357/ac33a8
project
A unified picture of white dwarf planetary systems
language
English
LU publication?
yes
id
4b803f30-4ed7-4d2b-ba29-26fc02980ce8
date added to LUP
2022-02-16 13:21:28
date last changed
2024-04-18 05:40:01
@article{4b803f30-4ed7-4d2b-ba29-26fc02980ce8,
  abstract     = {{<p>White dwarfs (WDs) often show metal lines in their spectra, indicating accretion of asteroidal material. Our Sun is to become a WD in several gigayears. Here, we examine how the solar WD accretes from the three major small body populations: the main belt asteroids (MBAs), Jovian Trojan asteroids (JTAs), and trans-Neptunian objects (TNOs). Owing to the solar mass loss during the giant branch, 40% of the JTAs are lost but the vast majority of MBAs and TNOs survive. During the WD phase, objects from all three populations are sporadically scattered onto the WD, implying ongoing accretion. For young cooling ages ≲100 Myr, accretion of MBAs predominates; our predicted accretion rate ∼106 g s-1 falls short of observations by two orders of magnitude. On gigayear timescales, thanks to the consumption of the TNOs that kicks in ⪆100 Myr, the rate oscillates around 106-107 g s-1 until several gigayears and drops to ∼105 g s-1 at 10 Gyr. Our solar WD accretion rate from 1 Gyr and beyond agrees well with those of the extrasolar WDs. We show that for the solar WD, the accretion source region evolves in an inside-out pattern. Moreover, in a realistic small body population with individual sizes covering a wide range as WD pollutants, the accretion is dictated by the largest objects. As a consequence, the accretion rate is lower by an order of magnitude than that from a population of bodies of a uniform size and the same total mass and shows greater scatter.</p>}},
  author       = {{Li, Daohai and Mustill, Alexander J. and Davies, Melvyn B.}},
  issn         = {{0004-637X}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{2}},
  publisher    = {{American Astronomical Society}},
  series       = {{Astrophysical Journal}},
  title        = {{Metal Pollution of the Solar White Dwarf by Solar System Small Bodies}},
  url          = {{http://dx.doi.org/10.3847/1538-4357/ac33a8}},
  doi          = {{10.3847/1538-4357/ac33a8}},
  volume       = {{924}},
  year         = {{2022}},
}