The Astronomical Journal - latest papers

Latest articles for The Astronomical Journal
  1. Erratum: “Astrometric Membership Tests for the Zinn–Newell–Gibson UV-bright Stars in Galactic Globular Clusters” ( 2021, AJ, 161, 204 [] )
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  2. Validation of 13 Hot and Potentially Terrestrial TESS Planets
    The James Webb Space Telescope will be able to probe the atmospheres and surface properties of hot, terrestrial planets via emission spectroscopy. We identify 18 potentially terrestrial planet candidates detected by the Transiting Exoplanet Survey Satellite (TESS) that would make ideal targets for these observations. These planet candidates cover a broad range of planet radii ( R p ∼ 0.6–2.0 R ⊕ ) and orbit stars of various magnitudes ( K s = 5.78–10.78, V = 8.4–15.69) and effective temperatures ( T eff ∼ 3000–6000 K). We use ground-based observations collected through the TESS Follow-up Observing Program (TFOP) and two vetting tools— DAVE and TRICERATOPS —to assess the reliabilities of these candidates as planets. We validate 13 planets: TOI-206 b, TOI-500 b, TOI-544 b, TOI-833 b, TOI-1075 b, TOI-1411 b, TOI-1442 b, TOI-1693 b, TOI-1860 b, TOI-2260 b, TOI-2411 b, TOI-2427 b, and T...
  3. Red Variable Stars in Three M81 Group Dwarf Galaxies
    Archival [3.6] and [4.5] images are used to identify and characterize variable stars in the Magellanic-type galaxies Holmberg II, NGC 2366, and IC 2574. Using parametric and nonparametric detection methods, 74 confirmed or suspected long-period variables (LPVs) are found. The period distributions of the LPVs in NGC 2366 and IC 2574 are similar. While the period distribution of LPVs in Ho II is uncertain due to small number statistics, there appears to be a deficiency of LPVs with periods between 550 and 650 days when compared with NGC 2366 and IC 2574. The LPVs are diffusely distributed on the sky, and do not follow the underlying light from unresolved stars, as expected if episodes of star formation within the past few hundred megayears have occurred throughout the galaxies, including their outer regions. Distances computed for Ho II and NGC 2366 from the period–luminosity relations (PLRs) agree to within ∼0.1 mag with those based on the tip of the red giant branch (RGB). Effor...
  4. Algorithmic Pulsar Timing
    Pulsar timing is a process of iteratively fitting pulse arrival times to constrain the spindown, astrometric, and possibly binary parameters of a pulsar, by enforcing integer numbers of pulsar rotations between the arrival times. Phase connection is the process of unambiguously determining those rotation numbers between the times of arrival while determining a pulsar timing solution. Pulsar timing currently requires a manual process of step-by-step phase connection performed by individuals. In an effort to quantify and streamline this process, we created the Algorithmic Pulsar Timer (APT), an algorithm that can accurately phase connect and time isolate pulsars. Using the statistical F-test and knowledge of parameter uncertainties and covariances, the algorithm decides what new data to include in a fit, when to add additional timing parameters, and which model to attempt in subsequent iterations. Using these tools, the algorithm can phase-connect timing data that previously requi...
  5. The Scorpion Planet Survey: Wide-orbit Giant Planets Around Young A-type Stars
    The first directly imaged exoplanets indicated that wide-orbit giant planets could be more common around A-type stars. However, the relatively small number of nearby A-stars has limited the precision of exoplanet demographics studies to ≳10%. We aim to constrain the frequency of wide-orbit giant planets around A-stars using the VLT/SPHERE extreme adaptive optics system, which enables targeting ≳100 A-stars between 100 and 200 pc. We present the results of a survey of 84 A-stars within the nearby ∼5–17 Myr old Sco OB2 association. The survey detected three companions—one of which is a new discovery (HIP 75056Ab), whereas the other two (HD 95086b and HIP 65426b) are now-known planets that were included without a priori knowledge of their existence. We assessed the image sensitivity and observational biases with injection and recovery tests combined with Monte Carlo simulations to place constraints on the underlying demographics. We measure a decreasing frequency of giant planets w...

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