Astrometry Archives

The results of our injection-recovery experiments on the synthetic data in the case of σRV, inst = 1.2 m s−1 (i.e., the “HIRES” case for internal RV precision) and σRV, astro = 0.4 m s−1 (i.e., the “quiet” case for stellar jitter). Each panel represents a combination of P (columns) and Mp (rows) for the known planet, which is shown as the white star plotted at P = Pknown and K = Kbaseline, and whose the error bar (which is smaller than the size of the marker see in some cases) represents σKbaseline . Filled squares represent individual injected companions that failed to trigger a detection from RVSearch. The color of each square represents the difference between Kfit and Kbaseline for the known planet from a one-planet fit to the synthetic RVs that now contains the signal of the undetected companion. The contours represent loci of 90%, 50%, and 10% detection efficiency. -- astro-ph.EP

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

The Impact of Observing Cadence and Undetected Companions on the Accuracy of Planet Mass Measurements From Radial Velocity Monitoring

by Keith CowingNovember 7, 2024November 7, 2024

We conduct experiments on both real and synthetic radial velocity (RV) data to quantify the impact that observing cadence, the number of RV observations, and undetected companions all have on […]

Comparative plot for the discovery spaces of Gaia and Theia, emphasizing Theia higher precision which enables the exploration of a new discovery space (data extracted from the 22-Oct-2024 version of the Encyclopaedia of exoplanetary systems catalog). -- astro-ph.EP

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

High Precision Astrometry Science In The Context of Space Mission Prospectives

by Keith CowingOctober 31, 2024October 31, 2024

Astrometry is one of the oldest branches of astronomy which measures the position, the proper motion and parallax of celestial objects.

Family portraits of the systems in the middle of the primary eclipse. The secondary moves horizontally across the disk of the primary. Shading for the secondary corresponds to the uncertainty in the posterior values of secondary radius. All systems are drawn to the same scale within boxes that are 6 R⊙ in length. -- astro-ph.SR

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

Five New Eclipsing Binaries With Low-mass Companions

by Keith CowingAugust 15, 2024August 15, 2024

Precise space-based photometry from the Transiting Exoplanet Survey Satellite results in a huge number of exoplanetary candidates. However, the masses of these objects are unknown and must be determined by […]

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 […]

Illustration of the positions and proper motions that Hipparcos and Gaia would measure for the same hypothetical orbit but with six different periods. The orbits shown have had parallactic and proper motion removed (c.f. Figure 1). The small colored ellipses show the quasi-one-dimensional position measurements made by Hipparcos and Gaia, the diamonds show the best-fit positions at Jyr 1991.25 and 2016.0 from fitting straight lines to the blue and orange points, respectively, and the arrows show the best-fit proper motions. The portions of the orbit covered by Hipparcos and Gaia are indicated by shading on the orbit, and a black arrow indicates the (counterclockwise) direction of orbital motion. Differences between the Hipparcos proper motion, the Gaia proper motion, and the scaled difference between the Hipparcos and Gaia positions can constrain orbital motion. At short periods (top middle and especially top left), the positions and proper motions can bear little resemblance to the instantaneous position and proper motion at the average epoch of observation, while at long periods (lower right) this distinction becomes insignificant. For all periods shown other than 50 years the star completes more than one full orbit between the Hipparcos and Gaia central epochs. -- astro-ph.IM

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

Astrometry As A Tool For Discovering And Weighing Faint Companions To Nearby Stars

by Keith CowingJune 21, 2024June 21, 2024

This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to measure the […]

Cumulative fraction of 350 systems that destabilized within 25 Myr. 99 % of the non-resonant systems with properties consistent with the observations were unstable, as opposed to 11 % of systems initialized in a six-planet resonant chain (via a disk migration simulation). Systems in which only a subset of the planets are captured into a resonant chain were also mostly unstable. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography, TRAPPIST-1

The Six-planet Resonant Chain Of HD 110067

by Keith CowingMay 10, 2024May 10, 2024

HD 110067 is the brightest star known to have six transiting planets. Each adjacent pair of planets has a period ratio that is nearly equal to a ratio of small […]

Characteristics of the exoplanets within the simulated event. Exoplanets exhibiting detectable radio signals are highlighted in orange. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Magnetic Fields, Electromagnetism, bioelectricity,, Status Report

Infrared-Radio-follow-up Observations for Detection of the Magnetic Radio Emission of Extra-Solar Planets: A New Window to Detect Exoplanets

by Keith CowingApril 23, 2024April 23, 2024

There are several methods for indirectly detecting exoplanets, such as transit, radial velocity, astrometry, and the conventional gravitational microlensing approach. These methods rely on observing the effects of exoplanets on […]

Empirical, non-parametric radius distribution of planets hosted by late K- and early M-type dwarfs observed by Kepler and assigned ages based on rotation, corrected for detection efficiency. The black line is the total distribution (113 planets), while the red and blue lines are the distributions for the halves of the sample with rotation-based ages younger and older than the median age of 3.86 Gyr, respectively. Shaded regions denote 68% confidence interval determined from Monte Carlo sampling with replacement. The vertical magenta lines mark the location (and uncertainty) of the radius valley using Eqn. 11 in Ho & Van Eylen (2023) for the sample’s median mass of 0.59 M⊙ and median period of 7.1 days. -- astro-ph.EP

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

The Radius Distribution Of M dwarf-hosted Planets And Its Evolution

by Keith CowingApril 18, 2024April 18, 2024

M dwarf stars are not only the most promising hosts for detection and characterization of small and potentially habitable planets, they provide leverage relative to solar-type stars to test models […]

Observed UCD candidates on a zoomed Gaia MG - G − J and G − GRP diagrams: UCDs are coloured by their obtained spectral type, as explained in Sect. 3. The two circled UCDs have peculiar colours (see text). Subdwarfs candidates are represented by crosses (see Sect. 4.1). Peculiar objects are represented by triangles (Sect. 4.2). The UCDs with common parallaxes and proper motions with another system are represented by diamonds (see Sect. 4.3) and those in (potentially) unresolved binary systems by squares (Sect. 4.4). The grey points are the sources from the Gaia Catalogue of Nearby Stars, with a RUWE < 1.4. The insets illustrate the locus of our sample on entire GaiaCatalogue of Nearby stars colour-absolute magnitude diagrams. -- astro-ph.SR

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

Near-infrared Spectroscopic Characterisation Of Gaia Ultra-cool Dwarf Candidates; Spectral Types And Peculiarities

by Keith CowingFebruary 16, 2024February 16, 2024

Context: The local census of very low-mass stars and brown dwarfs is crucial to improving our understanding of the stellar-substellar transition and their formation history. These objects, known as ultra-cool […]

Left: Histogram of the number of cold Jupiters that should be detected as a function of the size of the inner planet. Right: Scatter plot of stellar distance vs. stellar effective temperature of all TOIs. Color represents the probability of detecting the cold Jupiter. -- astro-ph.EP

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

Prospects From TESS And Gaia To Constrain The Flatness Of Planetary Systems

by Keith CowingDecember 11, 2023December 11, 2023

The mutual inclination between planets orbiting the same star provides key information to understand the formation and evolution of multi-planet systems.

Astrometry

The Impact of Observing Cadence and Undetected Companions on the Accuracy of Planet Mass Measurements From Radial Velocity Monitoring

High Precision Astrometry Science In The Context of Space Mission Prospectives

Five New Eclipsing Binaries With Low-mass Companions

Sun-like Stars Have Been Found Orbiting Hidden Companions

Astrometry As A Tool For Discovering And Weighing Faint Companions To Nearby Stars

The Six-planet Resonant Chain Of HD 110067

Infrared-Radio-follow-up Observations for Detection of the Magnetic Radio Emission of Extra-Solar Planets: A New Window to Detect Exoplanets

The Radius Distribution Of M dwarf-hosted Planets And Its Evolution

Near-infrared Spectroscopic Characterisation Of Gaia Ultra-cool Dwarf Candidates; Spectral Types And Peculiarities

Prospects From TESS And Gaia To Constrain The Flatness Of Planetary Systems

Tricorder Tech: New Handheld Device Maps Chemical Composition Using Infrared Light

No Statistically Significant Evidence For A Correlation Between Stellar And planetary Composition

Water Planet Recon: How Accurately Can We Measure Earth Ocean’s Deepest Point?

Webb Reveals A Stunning Panorama Of Star Formation

Deep Learning of SHERLOC Raman Spectra For Facilitating Mars Astromaterial Identification