Debris Disks: Structure, Composition, and Variability

Debris disks are tenuous, dust-dominated disks commonly observed around stars over a wide range of ages. Those around main sequence stars are analogous to the Solar System's Kuiper Belt and zodiacal light. The dust in debris disks is believed to be continuously regenerated, originating primarily with collisions of planetesimals. Observations of debris disks provide insight into the evolution of planetary systems; and the composition of dust, comets, and planetesimals outside the Solar System; as well as placing constraints on the orbital architecture and potentially the masses of exoplanets that are not otherwise detectable. This review highlights recent advances in multiwavelength, high-resolution scattered light and thermal imaging that have revealed a complex and intricate diversity of structures in debris disks and discusses how modeling methods are evolving with the breadth and depth of the available observations. Two rapidly advancing subfields highlighted in this review include observations of atomic and molecular gas around main sequence stars and variations in emission from debris disks on very short (days to years) timescales, providing evidence of non-steady-state collisional evolution particularly in young debris disks.

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Characterizing planetesimal belts through the study of debris dust

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311019934 ◽

2010 ◽

Vol 6 (S276) ◽

pp. 54-59

Author(s):

Amaya Moro-Martín

Keyword(s):

Solar System ◽

Main Sequence ◽

Planetary Systems ◽

Dust Particles ◽

Debris Disks ◽

Main Sequence Stars ◽

Wide Range ◽

Robust Process

AbstractMain sequence stars are commonly surrounded by disks of dust. From lifetime arguments, it is inferred that the dust particles are not primordial but originate from the collision of planetesimals, similar to the asteroids, comets and KBOs in our Solar system. The presence of these debris disks around stars with a wide range of masses, luminosities, and metallicities, with and without binary companions, is evidence that planetesimal formation is a robust process that can take place under a wide range of conditions. Debris disks can help us learn about the formation, evolution and diversity of planetary systems.

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TESS Giants Transiting Giants. I.: A Noninflated Hot Jupiter Orbiting a Massive Subgiant

The Astronomical Journal ◽

10.3847/1538-3881/ac38a1 ◽

2022 ◽

Vol 163 (2) ◽

pp. 53

Author(s):

Nicholas Saunders ◽

Samuel K. Grunblatt ◽

Daniel Huber ◽

Karen A. Collins ◽

Eric L. N. Jensen ◽

...

Keyword(s):

Main Sequence ◽

Planetary System ◽

Scattered Light ◽

Image Data ◽

Velocity Measurements ◽

Main Sequence Stars ◽

Transiting Planets ◽

Depth Difference ◽

Evolved Stars ◽

Hot Jupiter

Abstract While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confirmation of a hot Jupiter orbiting TOI-2184 (TIC 176956893), a massive evolved subgiant (M ⋆ = 1.53 ± 0.12 M ⊙, R ⋆ = 2.90 ± 0.14 R ⊙) in the Transiting Exoplanet Survey Satellite (TESS) Southern Continuous Viewing Zone. The planet was flagged as a false positive by the TESS Quick-Look Pipeline due to periodic systematics introducing a spurious depth difference between even and odd transits. Using a new pipeline to remove background scattered light in TESS Full Frame Image data, we combine space-based TESS photometry, ground-based photometry, and ground-based radial velocity measurements to report a planet radius of R p = 1.017 ± 0.051 R J and mass of M p = 0.65 ± 0.16 M J . For a planet so close to its star, the mass and radius of TOI-2184b are unusually well matched to those of Jupiter. We find that the radius of TOI-2184b is smaller than theoretically predicted based on its mass and incident flux, providing a valuable new constraint on the timescale of post-main-sequence planet inflation. The discovery of TOI-2184b demonstrates the feasibility of detecting planets around faint (TESS magnitude > 12) post-main-sequence stars and suggests that many more similar systems are waiting to be detected in the TESS FFIs, whose confirmation may elucidate the final stages of planetary system evolution.

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Circumstellar Disks and Star Formation

Highlights of Astronomy ◽

10.1017/s1539299600009229 ◽

1992 ◽

Vol 9 ◽

pp. 377-380

Author(s):

L. Hartmann ◽

M. Gomez ◽

S.J. Kenyon

Keyword(s):

Star Formation ◽

Spectral Region ◽

Main Sequence ◽

Circumstellar Disks ◽

Central Star ◽

Disk Accretion ◽

Main Sequence Stars ◽

Excess Emission ◽

Infrared Spectral ◽

The Masses

Results from the IRAS satellite showed that many pre-main sequence stars exhibited unexpectedly large fluxes in the infrared spectral region. Several studies have shown that the simplest and most satisfying explanation of this excess emission is that it arises in optically-thick, dusty, circumstellar disks (Rucinski 1985; Adams, Lada, and Shu 1987, 1988; Kenyon and Hartmann 1987; Bertout, Basri, and Bouvier 1988; Basri and Bertout 1989). The masses of these disks are estimated to range between 10-3M⊙ to 1M⊙ (Beckwith et al. 1990; Adams et al. 1990), large enough that disk accretion may have a significant effect on the evolution of the central star. Indeed, Mercer-Smith, Cameron, and Epstein (1984) suggested that stars are essentially completely accreted from disks, rather than formed from quasi-spherical accretion (Stabler 1983, 1988).

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A Spectroscopic and Photometric Survey for Pre-Main Sequence Binaries

Symposium - International Astronomical Union ◽

10.1017/s0074180900225187 ◽

2001 ◽

Vol 200 ◽

pp. 165-168 ◽

Cited By ~ 3

Author(s):

Eike W. Guenther ◽

Viki Joergens ◽

Ralph Neuhäuser ◽

Guillermo Torres ◽

Natalie Stout Batalha ◽

...

Keyword(s):

Radial Velocity ◽

Main Sequence ◽

Spectroscopic Binaries ◽

Main Sequence Stars ◽

Current State ◽

Short Period ◽

Velocity Variations ◽

The Masses ◽

Stellar Masses ◽

Crucial Test

We give here an overview of the current state of our survey for pre-main sequence spectroscopic binaries. Up to now we have taken 739 spectra of 250 pre-main sequence stars. We find that 8% of the stars show significant radial velocity variations, and are thus most likely spectroscopic binaries. In addition to the targets showing radial velocity variations, 6% of the targets are double-lined spectroscopic binaries i.e., the total fraction of spectroscopic binaries is expected to be about 14%. All short-period SB2s are monitored photometrically in order to search for eclipses. An eclipsing SB2 would allow the direct measurement of the masses of both stellar components. Measurements of the stellar masses together with determinations of the stellar radii are a crucial test of evolutionary tracks of pre-main sequence stars.

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Absolute parameters of three southern eclipsing binaries: DQ Car, BK Ind, and V4396 Sgr

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa438 ◽

2020 ◽

Vol 493 (2) ◽

pp. 2659-2675

Author(s):

Derya Sürgit ◽

Ahmet Erdem ◽

Chris A Engelbrecht ◽

Fred Marang

Keyword(s):

South African ◽

Binary Stars ◽

Main Sequence ◽

Interstellar Extinction ◽

Eclipsing Binaries ◽

Evolutionary Status ◽

Distance Modulus ◽

Main Sequence Stars ◽

The Masses ◽

Absolute Parameters

ABSTRACT We present combined photometric and spectroscopic analyses of the three southern eclipsing binary stars: DQ Car, BK Ind, and V4396 Sgr. Radial velocity curves of these three systems were obtained at the South African Astronomical Observatory, and their light curves from the available data bases and surveys were used for the analysis. 75 new times of minima for these three eclipsing binaries were derived, and their ephemerides were updated. Only the O–C diagram of DQ Car indicates a cyclical variation, which was interpreted in terms of the light-time effect due to a third body in the system. Our final models describe these three systems as Algol-like binary stars with detached configurations. The masses and radii were found to be M1 = 1.86(±0.17) M⊙, R1 = 1.63(±0.06) R⊙ and M2 = 1.74(±0.17) M⊙, R2 = 1.52(±0.07) R⊙ for the primary and secondary components of DQ Car; M1 = 1.16(±0.05) M⊙, R1 = 1.33(±0.03) R⊙ and M2 = 0.98(±0.04) M⊙, R2 = 1.00(±0.03) R⊙ for BK Ind; and M1 = 3.14(±0.22) M⊙, R1 = 3.00(±0.09) R⊙ and M2 = 3.13(±0.24) M⊙, R2 = 2.40(±0.08) R⊙ for V4396 Sgr, respectively. The distances to DQ Car, BK Ind, and V4396 Sgr were derived to be 701(±50), 285(±20), and 414(±30) pc from the distance modulus formula, taking into account interstellar extinction. The evolutionary status of these three systems was also studied. It has been found that the components of DQ Car are very young stars at the age of ∼25 Myr and those of BK Ind and V4396 Sgr are evolved main-sequence stars at the ages of ∼2.69 Gyr and ∼204 Myr, respectively.

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Chemically Peculiar Stars Among Spectroscopic Binaries – Revisited

International Astronomical Union Colloquium ◽

10.1017/s025292110002039x ◽

1993 ◽

Vol 138 ◽

pp. 137-142 ◽

Cited By ~ 1

Author(s):

Wilhelm Seggewiss

Keyword(s):

Relative Frequency ◽

Main Sequence ◽

Statistical Investigation ◽

Spectroscopic Binaries ◽

Main Sequence Stars ◽

Eccentric Orbits ◽

Peculiar Stars ◽

Orbital Periods ◽

Chemically Peculiar Stars ◽

The Masses

AbstractThis paper presents a new statistical investigation of peculiar A-type stars (Am, Ap, Hg-Mn) among spectroscopic binary (SB) stars. The relative frequency of Am (CP 1) stars is 55% in the spectral range A1 to A6 of main-sequence stars. The Ap (CP 2) stars amount to 15% in the range B9 to A2. The Hg-Mn stars are concentrated to the spectral types B8 to AO and reach a relative frequency of 23%. The Am SB stars have the shortest orbital periods and the smallest eccentricities (30% circular) whereas the Ap SB stars show a strong tendency to long periods and highly eccentric orbits (only 10% circular). The masses of the Am stars agree with the masses of non-peculiar SB stars of corresponding spectral type.

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KIC 5359678: A detached eclipsing binary with starspots

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab1219 ◽

2021 ◽

Author(s):

Jiaxin Wang ◽

Jianning Fu ◽

Hubiao Niu ◽

Yang Pan ◽

Chunqian Li ◽

...

Keyword(s):

Main Sequence ◽

Function Analysis ◽

Light Curves ◽

Main Sequence Stars ◽

Period Range ◽

Eclipsing Binary ◽

A Value ◽

Auto Correlation ◽

Auto Correlation Function ◽

The Masses

Abstract We study the detached eclipsing binary, KIC 5359678, with starspot modulation using the high-quality Kepler photometry and LAMOST spectroscopy. The PHOEBE model, optimal for this binary, reveals that this system is a circular detached binary, composed of two F-type main-sequence stars. The masses and radii of the primary and the secondary are M1 = 1.31 ± 0.05M⊙, R1 = 1.52 ± 0.04R⊙, M2 = 1.12 ± 0.04M⊙, and R2 = 1.05 ± 0.06R⊙, respectively. The age of this binary is estimated to be about 2Gyr, a value much longer than the synchronization timescale of 17.8 Myr. The residuals of light curves show quasi-sinusoidal signals, which could be induced by starspots. We apply auto-correlation function analysis on the out-of-eclipse residuals and find that the spot with rotational period close to the orbital period, while, the decay timescale of starspots is longer than that on the single stars with the same temperature, period range, and rms scatter. A two-starspot model is adopted to fit the signals with two-dip pattern, whose result shows that the longitude decreases with time.

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