J/MNRAS/492/2683 Are exoplanetesimals differentiated? (Bonsor+, 2020)
Are exoplanetesimals differentiated?
Bonsor A., Carter P.J., Hollands M., Gansicke B.T., Leinhardt Z.,
Harrison J.H.D.
<Mon. Not. R. Astron. Soc., 492, 2683-2697 (2020)>
=2020MNRAS.492.2683B 2020MNRAS.492.2683B (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, white dwarf ; Abundances, peculiar ;
Effective temperatures ; Spectra, optical
Keywords: planets and satellites: general - circumstellar matter -
planetary systems - white dwarfs
Abstract:
Metals observed in the atmospheres of white dwarfs suggest that many
have recently accreted planetary bodies. In some cases, the
compositions observed suggest the accretion of material dominantly
from the core (or the mantle) of a differentiated planetary body.
Collisions between differentiated exoplanetesimals produce such
fragments. In this work, we take advantage of the large numbers of
white dwarfs where at least one siderophile (core-loving) and one
lithophile (rock-loving) species have been detected to assess how
commonly exoplanetesimals differentiate. We utilize N-body simulations
that track the fate of core and mantle material during the collisional
evolution of planetary systems to show that most remnants of
differentiated planetesimals retain core fractions similar to their
parents, while some are extremely core rich or mantle rich. Comparison
with the white dwarf data for calcium and iron indicates that the data
are consistent with a model in which 66+4-6 per cent have accreted
the remnants of differentiated planetesimals, while 31+5-5 per
cent have Ca/Fe abundances altered by the effects of heating (although
the former can be as high as 100 per cent, if heating is ignored).
These conclusions assume pollution by a single body and that
collisional evolution retains similar features across diverse
planetary systems. These results imply that both collisions and
differentiation are key processes in exoplanetary systems. We
highlight the need for a larger sample of polluted white dwarfs with
precisely determined metal abundances to better understand the process
of differentiation in exoplanetary systems.
Description:
The observational samples are collated from the literature; some are
the most highly polluted white dwarfs where multiple species have been
detected (Klein et al. 2011ApJ...741...64K 2011ApJ...741...64K; Zuckerman et al.
2011ApJ...739..101Z 2011ApJ...739..101Z; Dufour et al. 2012ApJ...749....6D 2012ApJ...749....6D; Gansicke et
al. 2012MNRAS.424..333G 2012MNRAS.424..333G; Jura et al. 2012ApJ...750...69J 2012ApJ...750...69J; Kawka &
Vennes 2012A&A...538A..13K 2012A&A...538A..13K, 2016MNRAS.458..325K 2016MNRAS.458..325K; Farihi, Gansicke &
Koester 2013Sci...342..218F 2013Sci...342..218F; Xu et al. 2013ApJ...766..132X 2013ApJ...766..132X; Raddi et
al. 2015MNRAS.450.2083R 2015MNRAS.450.2083R; Wilson et al. 2015MNRAS.451.3237W 2015MNRAS.451.3237W; Farihi et
al. 2016MNRAS.463.3186F 2016MNRAS.463.3186F; Hollands et al. 2017MNRAS.467.4970H 2017MNRAS.467.4970H, Cat.
J/MNRAS/467/4970; Swan et al. 2019MNRAS.490..202S 2019MNRAS.490..202S), while most are
cool (T*<9000K) DZs from Hollands et al. (2017MNRAS.467.4970H 2017MNRAS.467.4970H, Cat.
J/MNRAS/467/4970) and Hollands, Gansicke & Koester
(2018MNRAS.477...93H 2018MNRAS.477...93H).
We focus on a sample of white dwarfs where S/N>5 in this work (as
suggested by Hollands et al. 2018MNRAS.477...93H 2018MNRAS.477...93H), which includes 179
white dwarfs. Table A1 lists the Ca and Fe abundances of the sample
with associated errors, stellar temperatures, and references for all
measurements.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 63 179 The sample of polluted white dwarfs where both
calcium and iron were detected, as used in this
work
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name White dwarf name
21- 24 A4 --- Ref References (1)
26- 30 I5 K Teff Effective temperature
32- 37 F6.2 [-] [Ca/H] Ca/H abundance ratio
39- 42 F4.2 [-] e_[Ca/H] Error on Ca/H
44- 48 F5.2 [-] [Fe/H] Fe/H abundance ratio
50- 53 F4.2 [-] e_[Fe/H] Error on Fe/H
55- 58 F4.2 [-] [Ca/Fe] Ca/Fe abundance ratio
60- 63 F4.2 [-] e_[Ca/Fe] Error on Ca/Fe
--------------------------------------------------------------------------------
Note (1): References as follows:
1 = Jura et al. (2012ApJ...750...69J 2012ApJ...750...69J)
2 = Farihi et al. (2013Sci...342..218F 2013Sci...342..218F)
3 = Dufour et al. (2012ApJ...749....6D 2012ApJ...749....6D)
4 = Xu et al. (2013ApJ...766..132X 2013ApJ...766..132X)
5 = Zuckerman et al. (2011ApJ...739..101Z 2011ApJ...739..101Z)
6 = Klein et al. (2011ApJ...741...64K 2011ApJ...741...64K)
7 = Raddi et al. (2015MNRAS.450.2083R 2015MNRAS.450.2083R)
8 = Farihi et al. (2016MNRAS.463.3186F 2016MNRAS.463.3186F)
9 = Wilson et al. (2015MNRAS.451.3237W 2015MNRAS.451.3237W)
10 = Gansicke et al. (2012MNRAS.424..333G 2012MNRAS.424..333G)
11 = Hollands et al. (2017MNRAS.467.4970H 2017MNRAS.467.4970H, Cat. J/MNRAS/467/4970)
12 = Kawka & Vennes (2012A&A...538A..13K 2012A&A...538A..13K)
13 = Kawka & Vennes (2016MNRAS.458..325K 2016MNRAS.458..325K)
14 = Swan et al. (2019MNRAS.490..202S 2019MNRAS.490..202S)
15 = Jura et al. (2012ApJ...750...69J 2012ApJ...750...69J)
16 = Zuckerman et al. (2010ApJ...722..725Z 2010ApJ...722..725Z)
17 = Xu et al. (2014ApJ...783...79X 2014ApJ...783...79X)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 20-Mar-2023