Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs
Mustill, Alexander LU
and Villaver, Eva
(2012)
In The Astrophysical Journal
761(2).
- Abstract
- The search for planets around white dwarf stars, and evidence for dynamical instability around them in the form of atmospheric pollution and circumstellar disks, raises questions about the nature of planetary systems that can survive the vicissitudes of the asymptotic giant branch (AGB). We study the competing effects, on planets at several AU from the star, of strong tidal forces arising from the star's large convective envelope, and of the planets' orbital expansion due to stellar mass loss. We study, for the first time, the evolution of planets while following each thermal pulse on the AGB. For Jovian planets, tidal forces are strong, and can pull into the envelope planets initially at ~3 AU for a 1 M ☉ star and ~5 AU for a 5 M ☉ star.... (More)
- The search for planets around white dwarf stars, and evidence for dynamical instability around them in the form of atmospheric pollution and circumstellar disks, raises questions about the nature of planetary systems that can survive the vicissitudes of the asymptotic giant branch (AGB). We study the competing effects, on planets at several AU from the star, of strong tidal forces arising from the star's large convective envelope, and of the planets' orbital expansion due to stellar mass loss. We study, for the first time, the evolution of planets while following each thermal pulse on the AGB. For Jovian planets, tidal forces are strong, and can pull into the envelope planets initially at ~3 AU for a 1 M ☉ star and ~5 AU for a 5 M ☉ star. Lower-mass planets feel weaker tidal forces, and terrestrial planets initially within 1.5-3 AU enter the stellar envelope. Thus, low-mass planets that begin inside the maximum stellar radius can survive, as their orbits expand due to mass loss. The inclusion of a moderate planetary eccentricity slightly strengthens the tidal forces experienced by Jovian planets. Eccentric terrestrial planets are more at risk, since their eccentricity does not decay and their small pericenter takes them inside the stellar envelope. We also find the closest radii at which planets will be found around white dwarfs, assuming that any planet entering the stellar envelope is destroyed. Planets are in that case unlikely to be found inside ~1.5 AU of a white dwarf with a 1 M ☉ progenitor and ~10 AU of a white dwarf with a 5 M ☉ progenitor. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4500267
- author
- Mustill, Alexander
LU
and Villaver, Eva
- publishing date
- 2012
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics, planets and satellites: dynamical evolution and stability, stars: AGB and post-AGB, stars: evolution
- in
- The Astrophysical Journal
- volume
- 761
- issue
- 2
- article number
- 121
- publisher
- American Astronomical Society
- external identifiers
-
- scopus:84870776119
- DOI
- 10.1088/0004-637X/761/2/121
- language
- English
- LU publication?
- no
- id
- 7d5eb478-c926-4dfe-89ab-e60be048b322 (old id 4500267)
- date added to LUP
- 2016-04-04 10:15:54
- date last changed
- 2022-04-23 22:43:07
@article{7d5eb478-c926-4dfe-89ab-e60be048b322,
abstract = {{The search for planets around white dwarf stars, and evidence for dynamical instability around them in the form of atmospheric pollution and circumstellar disks, raises questions about the nature of planetary systems that can survive the vicissitudes of the asymptotic giant branch (AGB). We study the competing effects, on planets at several AU from the star, of strong tidal forces arising from the star's large convective envelope, and of the planets' orbital expansion due to stellar mass loss. We study, for the first time, the evolution of planets while following each thermal pulse on the AGB. For Jovian planets, tidal forces are strong, and can pull into the envelope planets initially at ~3 AU for a 1 M ☉ star and ~5 AU for a 5 M ☉ star. Lower-mass planets feel weaker tidal forces, and terrestrial planets initially within 1.5-3 AU enter the stellar envelope. Thus, low-mass planets that begin inside the maximum stellar radius can survive, as their orbits expand due to mass loss. The inclusion of a moderate planetary eccentricity slightly strengthens the tidal forces experienced by Jovian planets. Eccentric terrestrial planets are more at risk, since their eccentricity does not decay and their small pericenter takes them inside the stellar envelope. We also find the closest radii at which planets will be found around white dwarfs, assuming that any planet entering the stellar envelope is destroyed. Planets are in that case unlikely to be found inside ~1.5 AU of a white dwarf with a 1 M ☉ progenitor and ~10 AU of a white dwarf with a 5 M ☉ progenitor.}},
author = {{Mustill, Alexander and Villaver, Eva}},
keywords = {{Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics; planets and satellites: dynamical evolution and stability; stars: AGB and post-AGB; stars: evolution}},
language = {{eng}},
number = {{2}},
publisher = {{American Astronomical Society}},
series = {{The Astrophysical Journal}},
title = {{Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs}},
url = {{http://dx.doi.org/10.1088/0004-637X/761/2/121}},
doi = {{10.1088/0004-637X/761/2/121}},
volume = {{761}},
year = {{2012}},
}