Caballero identified the star 2MASS 19281982-2640123 as a potential Sun-like star from which the WOW! signal could have originated. We conducted a search for artificial narrowband (2.79 Hz/1.91 Hz), drifting (±4 Hz s−1) technosignatures from this source using the turboSETI pipeline, from 1–2 GHz, using simultaneous multi-telescope observations with both the Robert C. Byrd Green Bank Telescope and the newly refurbished Allen Telescope Array on 2022 May 21. Both telescope observations had an overlap of 580 s. While blind searches using radio telescopes have been conducted in the general field of view in which the WOW! signal was first detected, this is the first time a targeted search has been done. No technosignature candidates were detected.
The American Astronomical Society (AAS), established in 1899 and based in Washington, DC, is the major organization of professional astronomers in North America. Its membership of about 7,000 individuals also includes physicists, mathematicians, geologists, engineers, and others whose research and educational interests lie within the broad spectrum of subjects comprising contemporary astronomy. The mission of the AAS is to enhance and share humanity's scientific understanding of the universe.
The Institute of Physics (IOP) is a leading scientific society promoting physics and bringing physicists together for the benefit of all. It has a worldwide membership of around 50 000 comprising physicists from all sectors, as well as those with an interest in physics. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Its publishing company, IOP Publishing, is a world leader in professional scientific communications.
ISSN: 2515-5172
Research Notes of the AAS is a non-peer reviewed, indexed and secure record of works in progress, comments and clarifications, null results, or timely reports of observations in astronomy and astrophysics.
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Karen I. Perez et al 2022 Res. Notes AAS 6 197
A. Loeb et al 2024 Res. Notes AAS 8 39
We have conducted an extensive towed-magnetic-sled survey during the period 2023 June 14–28, over the seafloor about 85 km north of Manus Island, Papua New Guinea, centered around the calculated path of the bolide CNEOS 2014 January 8 (IM1). We found about 850 spherules of diameter 0.05–1.3 mm in our samples. They were analyzed by microXRF, Electron Probe Microanalyzer and ICP Mass spectrometry. We identified 22% of the spherules as the product of planetary igneous differentiation and labeled them as D-type spherules. A small portion of the D-spherules show an excess of Be, La and U, by up to three orders of magnitude relative to the solar system standard of CI chondrites, and a composition pattern that is distinctly different from coal fly ash.
Quanzhi Ye et al 2020 Res. Notes AAS 4 101
We report the recovery of returning Halley-type comet 12P/Pons-Brooks using the 4.3 m Lowell Discovery Telescope, at a heliocentric distance of 11.89 au. Comparative analysis with a dust model suggests that the comet may have been active since ∼30 au from the Sun. We derive a nuclear radius of 17 ± 6 km from the nucleus photometry, though this number is likely an overestimate due to the contamination from dust and gas. Continuing monitoring is encouraged in anticipation of the comet's forthcoming perihelion in 2024 April.
Sanja Lazarević et al 2024 Res. Notes AAS 8 107
We report the Australian Square Kilometre Array Pathfinder discovery of a new Galactic supernova remnant (SNR) candidate G308.73+1.38, which we name Raspberry. This new SNR candidate has an angular size of 207 × 167, and we measure a total integrated flux of 407 ± 50 mJy. We estimate Raspberry's most likely diameter of 10–30 pc which would place it at a distance 3–5 kpc, in the near side of the Milky Way's Scutum–Centaurus Arm. We also find a Stokes-V point source close to the center of Raspberry with a ∼5σ significance. This point source may be the remaining compact source, a neutron star, or possibly a pulsar, formed during the initial supernova event.
M. Mastropietro et al 2024 Res. Notes AAS 8 104
We analyzed the inactive nucleus of the main-belt comet 2010 LH15 at a true anomaly of 262°. Observations using the Gemini North Telescope in 2023 July yielded an absolute R-band magnitude of (18.4 ± 0.2) mag. Assuming a C-type geometric albedo and phase function, we estimated the nucleus radius to be (0.5 ± 0.1) km. The examination of the lightcurve profile did not yield clear evidence for a rotational period shorter than 2 hr.
Carmen Choza et al 2024 Res. Notes AAS 8 37
We describe archival observations and analysis of the HD 110067 planetary system using the Green Bank Telescope (GBT) as part of the Breakthrough Listen search for technosignatures. The star hosts six sub-Neptune planets in resonant orbits, and we tune the drift rate range of our search to match the properties of the system derived by Luque et al. Our observations cover frequencies from 1 to 11.2 GHz, using the GBT's L, S, C, and X-band receivers, to an equivalent isotropic radiated power limit of ∼3 × 1012 W. No technosignatures were found, but this unusual system remains an interesting target for future technosignature searches.
Laura A. Hayes and Peter T. Gallagher 2022 Res. Notes AAS 6 222
We report the detection of a significant sudden ionospheric disturbance in the D-region of Earth's ionosphere (∼60–100 km), which was associated with the massive γ-ray burst GRB 221009A that occurred on 2022 October 9. We identified the disturbance over northern Europe—a result of the increased ionization by X- and γ-ray emission from the GRB-using very low frequency radio waves as a probe of the D-region. These observations demonstrate that an extra-galactic GRB (z ∼ 0.151) can have a significant impact on the terrestrial atmosphere and illustrates that the Earth's ionosphere can be used as a giant X- and γ-ray detector. Indeed, these observations may provide an insight into the impacts of GRBs on the ionospheres of planets in our solar system and beyond.
Sangeeta Kumar and Maïssa Salama 2024 Res. Notes AAS 8 123
We present mass estimates and companion demographics on stellar multiples within 25 pc, using a survey of stars of all spectral types done by Robo-AO and supplemented by Gaia. The survey combined direct imaging by Robo-AO, a robotic adaptive optics instrument for 2 m class telescopes, to detect tight companions (<4'' separation) and with Gaia astrometry to detect wider co-moving companions. We estimated the masses for 267 companions using empirical relations and, for a subset of 97, dynamical mass estimates. We utilized previous mass–magnitude models using contrasts measured from Gaia and Robo-AO to estimate the mass and also used the orvara python package, a Markov Chain Monte Carlo orbit fitter using the companion astrometry and Hipparcos-Gaia proper motion accelerations, to estimate dynamical masses. We compare agreements and discrepancies in mass estimates from these two methods.
John E. Moores et al 2024 Res. Notes AAS 8 120
A complete understanding of methane in the atmosphere of Mars requires information on putative sources. Organic carbon derived from meteoritic sources, such as interplanetary dust particles (IDPs), over geologic time is the best-defined source of organic carbon on the surface of Mars. Here we examine two different mechanisms for degrading this material to produce methane (1) Ultraviolet photolysis and (2) thermal decomposition. Neither of these mechanisms can produce sufficient methane under realistic assumptions to explain observed methane at Gale Crater, suggesting that IDPs are not the primary source material producing methane on Mars.
Zhoujian Zhang 2024 Res. Notes AAS 8 114
AF Lep b is a rare directly imaged exoplanet with properties consistent with core-accretion evolution models. Using its precise dynamical mass and spectroscopically inferred bolometric luminosity alongside the Spiegel & Burrows evolution models, I determined an initial entropy >8.7 kB/baryon at 3σ and an age of 12 ± 4 Myr for AF Lep b. Comparing this planet's age to the isochrone age (24 ± 3 Myr) of its host association, the β Pictoris moving group (BPMG), suggests AF Lep b formed 12 ± 5 Myr later than its host star. Alternatively, the BPMG's updated kinematic age ( Myr) implies that AF Lep b formed 5 ± 5 Myr after its host star's formation, aligning more closely with protoplanetary disk dispersal timescales. The sensitivities of our findings to the planet's mass and luminosity are discussed. AF Lep b uniquely facilitates the constraints of its initial entropy and formation epoch, paving the way for similar insights into forthcoming exoplanet discoveries.
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Efrain Alvarado III et al 2024 Res. Notes AAS 8 134
The atmospheres of Ultracool Dwarfs (UCDs) are dominated by molecular chemistry, which makes their spectra and photometry particularly sensitive to elemental abundances. With lifespans in excess of the age of the universe, UCDs serve as chemical tracers in every component of the Milky Way. In this study, we present the Spectral ANalog of Dwarfs (SAND) grid of low-temperature model atmospheres that span Teff from 700 to 4000 K, from 4.0 to 6.0, [Fe/H] from −2.4 to +0.3, and a range of [α/Fe] that matches the Galactic distribution inferred from earlier spectroscopic surveys. The SAND grid primarily aims to model the spectra of brown dwarfs in the halo and thick disk of the Milky Way, and metal-poor UCDs in globular clusters.
Pieter van Dokkum et al 2024 Res. Notes AAS 8 135
CDG-1 is a tight grouping of four likely globular clusters in the Perseus cluster, and a candidate dark galaxy with little or no diffuse light. Here we provide new constraints on the luminosity of any underlying stellar emission, using Hubble Space Telescope/UVIS F200LP imaging. No diffuse emission is detected, with a 2σ upper limit of F200LP > 28.1 mag arcsec−2 on the 5'' scale of CDG-1. This surface brightness limit corresponds to a 2σ lower limit of >0.5 for the fraction of the total luminosity that is in the form of globular clusters. The most likely alternative, although improbable, is that CDG-1 is a chance grouping of four globular clusters in the halo of the Perseus galaxy IC 312.
Dimitris M. Christodoulou et al 2024 Res. Notes AAS 8 133
We analyze adjacent local pairs of mean-motion resonances (MMRs) between three orbiting bodies designed to produce a Laplace resonant phase angle φL or one of its multiples NφL, where integer N ≥ 2. This assumption yields a concrete pattern of Laplace resonances, very few of which (with angles φL and 2φL) have been observed in actual (extra)solar subsystems. All other MMRs face issues of proximity or remoteness of the orbits (they are too close or too far apart). We highlight one as yet unobservable MMR in each N-sequence for which these issues appear to be less acute.
Idel Waisberg et al 2024 Res. Notes AAS 8 131
Gamma Trianguli Australis is a nearby A-type star that was reported to be a 488 days astrometric binary in Gaia DR3. Here we report on a VLTI/GRAVITY observation of γ TrA in which we did not detect the companion down to a K band flux ratio of 0.5%. From the isochrone mass MA = 3.04M⊙ of the subgiant primary, this implies a semimajor axis aorb = 1.8 au and that the companion is a MB = 0.26M⊙ M dwarf. The primary disk is partially resolved with an angular diameter θ1 ≈ 1 mas ↔ 13.0R⊙. The differential visibility phases across the Brγ absorption line allowed us to measure the longitude of the ascending node of the primary's rotational plane Ωrot = 212° ± 3°. This implies a spin–orbit misalignment of at least 27° ± 3° based on the Gaia astrometric solution.
Mariel Lares-Martiz et al 2024 Res. Notes AAS 8 132
Gyrochronology is the empirical relation between rotation and age. NASA's Transiting Exoplanet Survey Satellite (TESS), Kepler, and K2 missions have observed thousands of wide main sequence binaries. Since components of a binary are coeval, their rotation periods should be consistent with gyrochronology models. However, the usefulness of gyrochronology depends upon reliable rotation periods. We explore the reliability of rotation period determinations for a sample of wide binary components from the TESS cycle 3. Wide binaries with the most reliable rotation period determinations provide a strong basis for testing whether the gyrochronology empirical relation derived from open clusters is also valid for field stars.