An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf

Fuente: arXiv
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Hauptverfasser: Zhang, Keming, Zang, Weicheng, El-Badry, Kareem, Lu, Jessica R., Bloom, Joshua S., Agol, Eric, Gaudi, B. Scott, Konopacky, Quinn, LeBaron, Natalie, Mao, Shude, Terry, Sean
Format: Preprint
Veröffentlicht: 2024
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author Zhang, Keming
Zang, Weicheng
El-Badry, Kareem
Lu, Jessica R.
Bloom, Joshua S.
Agol, Eric
Gaudi, B. Scott
Konopacky, Quinn
LeBaron, Natalie
Mao, Shude
Terry, Sean
author_facet Zhang, Keming
Zang, Weicheng
El-Badry, Kareem
Lu, Jessica R.
Bloom, Joshua S.
Agol, Eric
Gaudi, B. Scott
Konopacky, Quinn
LeBaron, Natalie
Mao, Shude
Terry, Sean
contents Terrestrial planets born beyond 1-3 AU have been theorized to avoid being engulfed during the red-giant phases of their host stars. Nevertheless, only a few gas-giant planets have been observed around white dwarfs (WDs) -- the end product left behind by a red giant. Here we report on evidence that the lens system that produced the microlensing event KMT-2020-BLG-0414 is composed of a WD orbited by an Earth-mass planet and a brown dwarf (BD) companion, as shown by the non-detection of the lens flux using Keck Adaptive Optics (AO). From microlensing orbital motion constraints, we determine the planet to be a $1.9\pm0.2$ Earth-mass ($M_\oplus$) planet at a physical separation of $2.1\pm0.2$ au from the WD during the event. By considering the system evolutionary history, we determine the BD companion to have a projected separation of 22 au from the WD, and reject an alternative model that places the BD at 0.2 au. Given planetary orbital expansion during the final evolutionary stages of the host star, this Earth-mass planet may have existed in an initial orbit close to 1 au, thereby offering a glimpse into the possible survival of planet Earth in the distant future.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02157
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf
Zhang, Keming
Zang, Weicheng
El-Badry, Kareem
Lu, Jessica R.
Bloom, Joshua S.
Agol, Eric
Gaudi, B. Scott
Konopacky, Quinn
LeBaron, Natalie
Mao, Shude
Terry, Sean
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Terrestrial planets born beyond 1-3 AU have been theorized to avoid being engulfed during the red-giant phases of their host stars. Nevertheless, only a few gas-giant planets have been observed around white dwarfs (WDs) -- the end product left behind by a red giant. Here we report on evidence that the lens system that produced the microlensing event KMT-2020-BLG-0414 is composed of a WD orbited by an Earth-mass planet and a brown dwarf (BD) companion, as shown by the non-detection of the lens flux using Keck Adaptive Optics (AO). From microlensing orbital motion constraints, we determine the planet to be a $1.9\pm0.2$ Earth-mass ($M_\oplus$) planet at a physical separation of $2.1\pm0.2$ au from the WD during the event. By considering the system evolutionary history, we determine the BD companion to have a projected separation of 22 au from the WD, and reject an alternative model that places the BD at 0.2 au. Given planetary orbital expansion during the final evolutionary stages of the host star, this Earth-mass planet may have existed in an initial orbit close to 1 au, thereby offering a glimpse into the possible survival of planet Earth in the distant future.
title An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2409.02157