binary star Archives

Graph of the semimajor axis and eccentricity of the final terrestrial planets in the simulations of Table 1. Note that the majority of the planets formed or reached their final orbits in the range of 0.45 – 0.65 au. -- astro-ph.EP

Secular Resonances in Planet-Hosting Binary Stars. II. Application to Terrestrial Planet Formation

by Keith CowingOctober 8, 2025October 8, 2025

Continuing our study of the effects of secular resonances on the formation of terrestrial planets in moderately close binary stars, we present here the results of an extensive numerical simulations […]

Schematic presentation of the system showing the binary star and the two planets orbiting the primary. The primary star is at the origin of the coordinate system. The indices I, O, S refer to the inner and outer planet, and the secondary star, respectively. -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Secular Resonances in Planet-Hosting Binary Stars. I. General Theory

by Keith CowingAugust 1, 2025August 1, 2025

Motivated by the diversity of circumstellar planets in binary stars and the strong effects of the secular resonances of Jupiter and Saturn on the formation and architecture of the inner […]

Field around TOI-6883 at two epochs. Left: 2MASS image (2002). Right: SDSS image (2011). The red cross indicates the approximate position of TOI-6883. The visible shift between the epochs is consistent with the proper motion measured by Gaia. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Characterization of the Visual BinaryTOI-6883AB and its Dynamical Implications for the Planetary companion TOI-6883Ab

by Keith CowingJune 13, 2025June 12, 2025

We demonstrate that TOI-6883 is a physically bound visual binary system composed of two solar-type stars, TOI-6883A (TIC 393818343) and TOI-6883B (TIC 393818340), initially regarded as a single star hosting […]

Schematic overview of the eccentric binary system TOI 4633 hosting an s-type planet in the habitable zone. The planet was discovered via the transit detection method which leaves the spatial orientation of its orbit unknown. It may either be (a) prograde, i.e., the planet and the companion star share the same sense of rotation, (b) highly inclined, or (c) retrograde as illustrated in the three panels. We find the planet likely to orbit retrograde in order to survive the periodic gravitational perturbations throughout the system’s lifetime of tage = 1.3 ± 0.3 Gyr. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Planet Formation And Long-term Stability In A Very Eccentric Stellar Binary

by Keith CowingJanuary 22, 2025January 22, 2025

Planets orbiting one of the two stars in a binary are vulnerable to gravitational perturbations from the other star.

How binary circularization might worsen the chances of detecting transiting planets they host, as viewed by a distant observer. For illustrative clarity, we display binaries which are not eclipsing. Top panel: When the planet forms prior to orbital decay, it can cross the binary orbital plane. Bottom panel: After orbital decay caused by tidal circularization, the planet no longer transits either component of the binary. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Concealing Circumbinary Planets With Tidal Shrinkage

by Keith CowingDecember 3, 2024December 3, 2024

Of the 14 transiting planets that have been detected orbiting eclipsing binaries (‘circumbinary planets’), none have been detected with stellar binary orbital periods shorter than 7 days, despite such binaries […]

Selection of the astrometric solutions for our mock astrometric binary catalog. This figure in inspired by Figure 3 of Halbwachs et al. (2023), who present the same quantities for the astrometric solutions of real sources published in Gaia DR3. Upper left panel shows all solutions with a0/σa0 > 5 and F2 < 25. The cloud of points at long Porb and low fm, ast consists mostly of good solutions, while the vertical stripes of solutions with high fm, ast and short periods are all spurious. In the upper right, green and gray show the distributions of solutions with fm, ast < 0.3 M⊙ (presumed mostly reliable) and fm, astt > 0.3 M⊙ (presumed mostly spurious). Black line shows the empirical cut (Equation 20) below which solutions are discarded. Bottom panels show only solutions that pass this cut. Red lines in these panels show additional cuts applied to the final solutions: only solutions below (left panel) and above (right panel) the red lines were retained. -- astro-ph.GA

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Stellar Cartography

A Generative Model for Gaia Astrometric Orbit Catalogs: Selection Functions for Binary Stars, Giant Planets, and Compact Object Companions

by Keith CowingNovember 7, 2024November 7, 2024

Astrometry from Gaia DR3 has produced a sample of ∼170,000 Keplerian orbital solutions, with many more anticipated in the next few years. These data have enormous potential to constrain the […]

Illustration from the book “Sur les autres mondes” (Rudaux 1937), with a planet surface illuminated by two suns of different colors. While the shadows’ colors might be realistic, modern stability criteria of circumbinary planet orbits imply that the angle between the shadows is too large, requiring a planet that is too close to the binary for a stable orbit. Credit: Photographic reproduction from original book by Lucien Rudaux (1874-1947), in public domain. -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report

The Way To Circumbinary Planets

by Keith CowingAugust 30, 2024August 29, 2024

Circumbinary planets (CBPs) are planets that orbit around both stars of a binary system. This chapter traces the history of research on CBPs and provides an overview over the current […]

Toomre diagram for the binary system TOI-1173 A/B indicating that our pair is located in the thin-disk. The stars, triangles and inverted triangles symbols represent stars from the thin-disk, thick-disk, and halo of the Galaxy, respectively, for context. Data taken from Ram´ırez et al. (2007) -- astro-ph.SR

Astropharmacy / Biotechnology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Detailed Abundances of the Planet-hosting TOI-1173 A/B system: Possible Evidence of Planet Engulfment in a Very Wide Binary

by Keith CowingAugust 11, 2024August 10, 2024

Over the last decade, studies of large samples of binary systems identified chemical anomalies, and showed that they might be attributed to planet formation or planet engulfment. However, both scenarios […]

Map of nearby potential direct imaging target stars, color-coded by spectral type. Stars with blue halos have available X-ray observations. The yellow star at the center of the diagram represents the Sun, with white concentric rings showing distances of 5 pc, 10 pc, and 15 pc. An animated version of this figure (8 seconds in duration) is available from the online journal showing the 3D distribution through different elevation and azimuthal angles (colors and symbols are the same as the static figure). -- astro-ph.HE

Astronomy & Telescopes, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

X-ray Emission of Nearby Low-mass and Sun-like Stars with Directly Imageable Habitable Zones

by Keith CowingAugust 2, 2024August 2, 2024

Stellar X-ray and UV radiation can significantly affect the survival, composition, and long-term evolution of the atmospheres of planets in or near their host star’s habitable zone (HZ).

This illustration depicts a binary star system consisting of a dense neutron star and a normal Sun-like star (upper left). Using data from the European Space Agency's Gaia mission, astronomers found several systems like this one, in which the two bodies are widely separated. Because the bodies in these systems are far apart, with separations on average 300 times the size of a Sun-like star, the neutron star is dormant—it is not actively stealing mass from its companion and is thus very faint. To find these hidden neutron stars, the scientists used Gaia observations to look for a wobble in the Sun-like stars caused by a tugging action of the orbiting neutron stars. These are the first neutron stars discovered purely due to their gravitational effects. As depicted in this illustration, the intense gravity of the compact neutron star—which is about 100,000 times smaller than the Sun-like star yet heavier—warps our view of the sky around it, producing a distorted mirrored view of the nearby star. Credit: Caltech/R. Hurt (IPAC)

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Radiation, Space Weather & Heliophysics, Stellar Cartography

Sun-like Stars Have Been Found Orbiting Hidden Companions

by Keith CowingJuly 29, 2024July 29, 2024

Most stars in our universe come in pairs. While our own Sun is a loner, many stars like our Sun orbit similar stars, while a host of other exotic pairings […]

binary star

Secular Resonances in Planet-Hosting Binary Stars. II. Application to Terrestrial Planet Formation

Secular Resonances in Planet-Hosting Binary Stars. I. General Theory

Characterization of the Visual BinaryTOI-6883AB and its Dynamical Implications for the Planetary companion TOI-6883Ab

Planet Formation And Long-term Stability In A Very Eccentric Stellar Binary

Concealing Circumbinary Planets With Tidal Shrinkage

A Generative Model for Gaia Astrometric Orbit Catalogs: Selection Functions for Binary Stars, Giant Planets, and Compact Object Companions

The Way To Circumbinary Planets

Detailed Abundances of the Planet-hosting TOI-1173 A/B system: Possible Evidence of Planet Engulfment in a Very Wide Binary

X-ray Emission of Nearby Low-mass and Sun-like Stars with Directly Imageable Habitable Zones

Sun-like Stars Have Been Found Orbiting Hidden Companions

Roman Space Telescope: Enabling Images Of Distant Worlds

NASA Solar System Exploration Research Virtual Institute (SSERVI) Cooperative Agreement Notice (NNH26ZDA016C) Final Text And Due Dates

Interstellar Aromatic Infrared Bands: IR Absorption Spectroscopy Of The Lowest Triplet State Of Naphthalene

The Highly Unusual Behavior And Chemical Composition Of Interstellar Comet 2I/Borisov

Volatile Depletion In Rocky Planets As A Chemical Fingerprint Of Hybrid Accretion