I show that Hawking radiation from a mini black hole with a mass of ∼1011 g in a low orbit around an otherwise frozen rogue planet, can supply the energy needs of a civilization on the surface of the planet. Maintaining this furnace for more than a few years requires a modest accretion rate of ∼2 kg s−1. The associated technosignature is detectable as a gamma-ray source occulted by a warm planet every 1–2 hr, with no stellar-mass companion.
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.
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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.
Abraham Loeb 2024 Res. Notes AAS 8 200
Abraham Loeb 2024 Res. Notes AAS 8 214
Relativistic interstellar objects (RISOs) are not constrained by astronomical sky surveys because they are smeared in sky images and at best appear in one frame. Here, I show that irrespective of their nature, RISOs more massive than ∼1014 g would have been detected by the LIGO-Virgo-KAGRA collaboration through their tidal gravitational signal at a frequency of f ∼ 50 Hz within a distance comparable to the Earth radius. This constrains the passage of relativistic primordial black holes or other exotic objects at the local mass density of dark matter near Earth over the past decade.
Abraham Loeb 2023 Res. Notes AAS 7 43
Without extensive maintenance, Dyson spheres inevitably disintegrate by asteroid impacts over billions of years. The resulting fragments would appear as anomalous interstellar objects, potentially sharing the unusual shape and motion of 1I/'Oumuamua or the unusual material strength of the first two interstellar meteors, IM1 and IM2. If the Dyson sphere's tiles are light sails, the number of fragments could exceed that of interstellar asteroids because of their reduced escape speed from the star and the increase in stellar luminosity during the red giant phase.
Carlos de la Fuente Marcos and Raúl de la Fuente Marcos 2024 Res. Notes AAS 8 184
Small solar system bodies may reach hyperbolic orbits after a close interaction with a giant planet. Comet C/1980 E1 (Bowell), with a current value of the eccentricity of 1.057733 ± 0.000008, reached its present-day path after a close encounter with Jupiter in 1980. Comet A117uUD was found by ATLAS South Africa on 2024 June 14. Its current orbit determination, based on 142 observations for a data-arc span of 31 days, places A117uUD among the bodies following hyperbolic orbits (19.51σ, eccentricity of 1.037 ± 0.002). However, it did not come from interstellar space. Here, we show that it reached its current hyperbolic trajectory after a close encounter with Saturn in 2022.
Carl Audric Guia et al 2024 Res. Notes AAS 8 207
The "Little Red Dots" (LRDs) are red and compact galaxies detected in JWST deep fields, mainly in the redshift range z = 4–8. Given their compactness and the inferred stellar masses in the hypothesis that LRDs are starburst galaxies, the implied stellar densities are immense. This Research Note uses an extensive catalog of LRDs from the PRIMER and the COSMOS-Web surveys to investigate these densities. We find a median (upper limit) on the effective radius of 80 pc, which leads to median (lower limit) values of the core density of ∼104 M⊙ pc−3, and individual densities as high as ∼108 M⊙ pc−3, which is ∼10 times higher than the density necessary for runaway collisions to take place. For ∼35% of the LRDs investigated, the lower limits are higher than the highest stellar densities observed in any system in any redshift range.
Carlos de la Fuente Marcos and Raúl de la Fuente Marcos 2024 Res. Notes AAS 8 224
Near-Earth objects (NEOs) that follow horseshoe paths, and approach our planet at close range and low relative velocity, may undergo mini-moon events in which their geocentric energy becomes negative for hours, days or months, but without completing one revolution around Earth while bound. An example of NEO experiencing such a temporarily captured flyby is 2022 NX1, which was a short-lived mini-moon in 1981 and 2022. Here, we show that the recently discovered small body 2024 PT5 follows a horseshoe path and it will become a mini-moon in 2024, from September 29 until November 25.
Aaron J. Romanowsky et al 2024 Res. Notes AAS 8 202
Two low surface brightness (LSB) dwarf galaxies were identified recently as having little or no dark matter (DM), provoking widespread interest in their formation histories. These galaxies also host populous systems of star clusters that are on average larger and more luminous than typical globular clusters (GCs). We report an initial attempt to identify new candidate DM-deficient dwarfs via their unusual GC systems. Using a large catalog of LSB galaxies from the Dark Energy Survey, we inspect their Dark Energy Camera Legacy Survey (DECaLS) imaging and identify FCC 224 as a candidate found on the outskirts of the Fornax cluster. We analyze the GC system using DECaLS and archival Hubble Space Telescope WFPC2 imaging, and find an apparent population of overluminous GCs. More detailed follow-up of FCC 224 is in progress.
Karen I. Perez et al 2022 Res. Notes AAS 6 197
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.
Karen L. Masters et al 2024 Res. Notes AAS 8 198
We present morphological classifications based on Galaxy Zoo analysis of 71,052 galaxies with imaging from the United Kingdom Infrared Telescope Infrared Deep Sky Survey (UKIDSS). Galaxies were selected out of the Galaxy Zoo 2 (GZ2) sample, so also have gri imaging from the Sloan Digital Sky Survey. An identical classification tree, and vote weighting/aggregation was applied to both UKIDSS and GZ2 classifications enabling direct comparisons. With this Research Note we provide a public release of the GZ:UKIDSS morphologies and discuss some initial comparisons with GZ2.
Valerio Carruba et al 2024 Res. Notes AAS 8 213
Venus has no known natural satellites but has 5 known co-orbitals. These are objects trapped in a 1:1 mean-motion resonance with Venus. Co-orbital configurations include retrograde satellite orbits (RS), tadpole orbits (T) around the Lagrangian equilibrium points L4 or L5, and horseshoe orbits around both L4 and L5 (H). At high eccentricity or inclination, co-orbital configurations may also involve compounds of T and RS (T-RS, T-RS-T), H and RS (H-RS) orbits, or transitions between different co-orbital modes. Here we identify asteroids in 2 RS, 1 L4-tadpole, 2 H-RS, and 2 T-RS orbits, as well as 8 additional asteroids in possible temporary co-orbital status. Although the majority of these objects do not yet have well-characterized orbits, 2020 CL1, and 2020 SB do and are very likely to be new co-orbital asteroids. With the new candidates, Venus would have a population of 20 co-orbital asteroids, comparable to those of Mars and Earth.
Zoutong Shen 2024 Res. Notes AAS 8 228
I present new transit and occultation timing measurements for the hot Jupiter WASP-12b using data from TESS Sectors 71 and 72, observed in 2023. Using full-phase curve fitting for the first time, I precisely locate both transits and occultations. I report 34 new transit times and sector-specific occultation times, updating the orbital decay rate to −26.310 ± 0.901 ms yr−1. My analysis strongly favors the orbital decay model over constant period and apsidal precession models.
Lucia Fisher et al 2024 Res. Notes AAS 8 227
Ultracool dwarfs (UCDs) are considered prime targets for galactic archeology due to their abundance, long lifespans, and the sensitivity of their spectra to chemical composition. To calibrate larger surveys, a sample of benchmark UCDs with robust abundances is necessary. We present [Fe/H], [α/Fe] and abundances of 13 elements, inferred from high-resolution spectra of 13 FGK primaries hosting a UCD companion. For a subset of our sample with APOGEE observations, individual abundances agree within 0.06 dex on average.
Valerio Carruba et al 2024 Res. Notes AAS 8 226
Maxwell K. Frissell et al 2024 Res. Notes AAS 8 225
We report the discovery of cometary activity emanating from minor planet 2015 VP51 outbound from its recent perihelion passage. The activity, in the form of a diffuse tail, was first identified by volunteers of our Citizen Science program Active Asteroids, a NASA Partner program hosted on the Zooniverse platform. This discovery was aided by the recently implemented TailNet artificial intelligence assistant which filters out images with a low likelihood of showing cometary activity. The tail is present in nine images of 2015 VP51 from the Dark Energy Camera and OmegaCAM between UT 2015 August 2 and UT 2015 October 18. We classify 2015 VP51 as a Jupiter-family comet based on its Tisserand parameter with respect to Jupiter TJ = 2.931.
Carlos de la Fuente Marcos and Raúl de la Fuente Marcos 2024 Res. Notes AAS 8 224
Near-Earth objects (NEOs) that follow horseshoe paths, and approach our planet at close range and low relative velocity, may undergo mini-moon events in which their geocentric energy becomes negative for hours, days or months, but without completing one revolution around Earth while bound. An example of NEO experiencing such a temporarily captured flyby is 2022 NX1, which was a short-lived mini-moon in 1981 and 2022. Here, we show that the recently discovered small body 2024 PT5 follows a horseshoe path and it will become a mini-moon in 2024, from September 29 until November 25.