東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Exoplanets in the Mid-to-Late M-Dwar...

Pass, Emily Katherine,

Linked to FindBook

Google Book

Amazon

博客來

Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs // Emily Katherine Pass.
Author:	Pass, Emily Katherine,
Description:	1 electronic resource (317 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
Contained By:	Dissertations Abstracts International85-12B.
Subject:	Astronomy. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31295833
ISBN:	9798382783802

Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs /
Pass, Emily Katherine,

Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs /Emily Katherine Pass. - 1 electronic resource (317 pages)

Source: Dissertations Abstracts International, Volume: 85-12, Section: B.

Low-mass M dwarfs (0.1-0.3M⊙) comprise over half of stars in the solar neighborhood. These tiny stars are ideal for exoplanet characterization, providing the highest-precision measurements of planetary masses and radii that enable envelope-pushing explorations of planetary atmospheres and bulk compositions. My work explores how these stars differ from our Sun and the consequences for attendant planets.The rotation periods of low-mass field M dwarfs are bimodal, suggesting an abrupt transition between fast and slow rotation rates. However, a detailed understanding of the spindown process has been stymied by difficulties in measuring M-dwarf ages. By studying M dwarfs in wide binaries with stars of known age, I observe gradual spindown within the rapidly rotating mode for a few billion years before the abrupt transition. There is, however, a large dispersion and some stars make the jump by 600Myr. I establish that G 68-34, the one star in my sample that did not follow this trend, is in fact an eclipsing binary. The pair has masses of 0.3280±0.0034M⊙ and 0.3207±0.0036M⊙, radii of 0.345±0.014R⊙ and 0.342±0.014R⊙, an orbital period of 0.655 days, and has maintained rapid rotation for >5Gyr due to tidal interactions. I also identify a strong mass dependence to the spindown process: 0.1M⊙ M dwarfs spin down to a quiescent state billions of years later on average than their 0.3M⊙ counterparts, at an average age of 4.4Gyr for 0.1M⊙, 2.8Gyr for 0.2M⊙, and 1.3Gyr for 0.3M⊙. By measuring the Hα activity of stars in M-M binaries (which presumably share a common age, metallicity, and high-energy birth environment), I find ≤0.5Gyr dispersion in the mass-dependent relation when these variables are controlled. The long active lifetimes of low-mass M dwarfs may imply that their terrestrial planets are unable to retain atmospheres.I also present a multi-epoch radial-velocity survey of the volume-complete sample of 0.1-0.3M⊙ M dwarfs within 15pc, which enables several studies: 1) For the 123 active, single stars, I measure rotation periods, Hα equivalent widths, inclinations, and radial velocities. I find that 92±3% of active, low-mass M dwarfs have rotation periods shorter than 20 days, with 74±4% having periods shorter than 2 days. Stars in the gap between the rapidly and slowly rotating modes have enhanced magnetic activity, perhaps reflecting a change in magnetic field structure during this phase of abrupt spindown; 2) I search the 200 inactive, single stars for giant planets. My null detection implies <1.7% of low-mass M dwarfs have a Jupiter-analog companion beyond the snow line, with 95% confidence. Terrestrial planets are abundant around low-mass M dwarfs, implying those worlds evolved in a very different dynamical environment to the rocky worlds of our solar system, with implications for their sizes, compositions, and habitability; 3) I calibrate a novel spectroscopic metallicity relation for mid-to-late M dwarfs, which I will use to estimate metallicities for the volume-complete sample. This relation leverages the metallicity sensitivity of the near-IR Ca II triplet, a strong feature deeply embedded in the metal lines of the pseudocontinuum; and 4) For one star in the survey, LTT 1445A, I analyze new HST photometry, finding that the transit of planet c is nongrazing with 97% confidence and thus the planet has a radius of 1.07-0.07+0.10R⊕ and a terrestrial composition. This star is the nearest M dwarf with transiting planets, making LTT 1445Ac one of the best opportunities to characterize a terrestrial exoplanetary atmosphere.

English

ISBN: 9798382783802Subjects--Topical Terms:

517668
Astronomy.
Subjects--Index Terms:

Exoplanets

Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs /
LDR:05112nmm a22004333i 4500 001 2433734
005 20250905091001.5
006 m o d
007 cr|nu||||||||
008 261011s2024 miu||||||m |||||||eng d
020 $a 9798382783802
035 $a (MiAaPQD)AAI31295833
035 $a AAI31295833
040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a Pass, Emily Katherine, $e author. $0 (orcid)0000-0002-1533-9029 $3 3823471
245 1 0 $a Exoplanets in the Mid-to-Late M-Dwarf Context: Insights on the Spindown of Fully Convective Stars and the Rarity of Their Jupiter Analogs / $c Emily Katherine Pass.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2024
300 $a 1 electronic resource (317 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
500 $a Advisors: Charbonneau, David Committee members: Oberg, Karin; Latham, David; Conroy, Charlie; Agueros, Marcel.
502 $b Ph.D. $c Harvard University $d 2024.
520 $a Low-mass M dwarfs (0.1-0.3M⊙) comprise over half of stars in the solar neighborhood. These tiny stars are ideal for exoplanet characterization, providing the highest-precision measurements of planetary masses and radii that enable envelope-pushing explorations of planetary atmospheres and bulk compositions. My work explores how these stars differ from our Sun and the consequences for attendant planets.The rotation periods of low-mass field M dwarfs are bimodal, suggesting an abrupt transition between fast and slow rotation rates. However, a detailed understanding of the spindown process has been stymied by difficulties in measuring M-dwarf ages. By studying M dwarfs in wide binaries with stars of known age, I observe gradual spindown within the rapidly rotating mode for a few billion years before the abrupt transition. There is, however, a large dispersion and some stars make the jump by 600Myr. I establish that G 68-34, the one star in my sample that did not follow this trend, is in fact an eclipsing binary. The pair has masses of 0.3280±0.0034M⊙ and 0.3207±0.0036M⊙, radii of 0.345±0.014R⊙ and 0.342±0.014R⊙, an orbital period of 0.655 days, and has maintained rapid rotation for >5Gyr due to tidal interactions. I also identify a strong mass dependence to the spindown process: 0.1M⊙ M dwarfs spin down to a quiescent state billions of years later on average than their 0.3M⊙ counterparts, at an average age of 4.4Gyr for 0.1M⊙, 2.8Gyr for 0.2M⊙, and 1.3Gyr for 0.3M⊙. By measuring the Hα activity of stars in M-M binaries (which presumably share a common age, metallicity, and high-energy birth environment), I find ≤0.5Gyr dispersion in the mass-dependent relation when these variables are controlled. The long active lifetimes of low-mass M dwarfs may imply that their terrestrial planets are unable to retain atmospheres.I also present a multi-epoch radial-velocity survey of the volume-complete sample of 0.1-0.3M⊙ M dwarfs within 15pc, which enables several studies: 1) For the 123 active, single stars, I measure rotation periods, Hα equivalent widths, inclinations, and radial velocities. I find that 92±3% of active, low-mass M dwarfs have rotation periods shorter than 20 days, with 74±4% having periods shorter than 2 days. Stars in the gap between the rapidly and slowly rotating modes have enhanced magnetic activity, perhaps reflecting a change in magnetic field structure during this phase of abrupt spindown; 2) I search the 200 inactive, single stars for giant planets. My null detection implies <1.7% of low-mass M dwarfs have a Jupiter-analog companion beyond the snow line, with 95% confidence. Terrestrial planets are abundant around low-mass M dwarfs, implying those worlds evolved in a very different dynamical environment to the rocky worlds of our solar system, with implications for their sizes, compositions, and habitability; 3) I calibrate a novel spectroscopic metallicity relation for mid-to-late M dwarfs, which I will use to estimate metallicities for the volume-complete sample. This relation leverages the metallicity sensitivity of the near-IR Ca II triplet, a strong feature deeply embedded in the metal lines of the pseudocontinuum; and 4) For one star in the survey, LTT 1445A, I analyze new HST photometry, finding that the transit of planet c is nongrazing with 97% confidence and thus the planet has a radius of 1.07-0.07+0.10R⊕ and a terrestrial composition. This star is the nearest M dwarf with transiting planets, making LTT 1445Ac one of the best opportunities to characterize a terrestrial exoplanetary atmosphere.
546 $a English
590 $a School code: 0084
650 4 $a Astronomy. $3 517668
650 4 $a Astrophysics. $3 535904
650 4 $a Planetology. $3 546174
653 $a Exoplanets
653 $a M dwarfs
653 $a Stars
653 $a Spindown
653 $a Terrestrial planets
690 $a 0606
690 $a 0596
690 $a 0590
710 2 $a Harvard University. $b Astronomy. $e degree granting institution. $3 3823472
720 1 $a Charbonneau, David $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 85-12B.
790 $a 0084
791 $a Ph.D.
792 $a 2024
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31295833