The Interstellar Interlopers

Jewitt, David; Seligman, Darryl Z.

doi:10.48550/arxiv.2209.08182

Cited by 11 publications

(15 citation statements)

References 119 publications

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“…Tentative constraints on the number density of free-floating icy worlds can be derived by extrapolating microlensing studies to a certain size threshold (Strigari et al 2012;Dai & Guerras 2018); the recent discovery of interstellar planetesimals has furnished additional data (Jewitt & Seligman 2022;Moro-Martín 2022). With regard to icy worlds that are gravitationally bound to stars, their number is sensitive to planetary system architecture, stellar spectral type, and so forth, thereby requiring a statistical (population) study.…”

Section: Model Setupmentioning

confidence: 99%

A Bayesian Analysis of Technological Intelligence in Land and Oceans

Lingam

Balbi

Mahajan

2023

ApJ

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Current research indicates that (sub)surface ocean worlds essentially devoid of subaerial landmasses (e.g., continents) are common in the Milky Way and that these worlds could host habitable conditions, thence raising the possibility that life and technological intelligence (TI) may arise in such aquatic settings. It is known, however, that TI on Earth (i.e., humans) arose on land. Motivated by these considerations, we present a Bayesian framework to assess the prospects for the emergence of TIs in land- and ocean-based habitats (LBHs and OBHs). If all factors are equally conducive for TIs to arise in LBHs and OBHs, we demonstrate that the evolution of TIs in LBHs (which includes humans) might have very low odds of roughly 1 in 103 to 1 in 104, thus outwardly contradicting the Copernican principle. Hence, we elucidate three avenues whereby the Copernican principle can be preserved: (i) the emergence rate of TIs is much lower in OBHs, (ii) the habitability interval for TIs is much shorter in OBHs, and (iii) only a small fraction of worlds with OBHs comprise appropriate conditions for effectuating TIs. We also briefly discuss methods for empirically falsifying our predictions and comment on the feasibility of supporting TIs in aerial environments.

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Section: Model Setupmentioning

confidence: 99%

A Bayesian Analysis of Technological Intelligence in Land and Oceans

Lingam

Balbi

Mahajan

2023

ApJ

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“…Additionally, 'Oumuamua had an extreme shape, a reddened reflection spectrum (Meech et al 2017), and a low incoming velocity indicating a young <40 Myr age (Feng & Jones 2018). Reconciling the lack of activity and the observed nongravitational perturbations remains a challenge (Jewitt & Seligman 2022), even though models have been proposed that could explain all the observed properties of 'Oumuamua, e.g., by assuming a significant presence of molecular hydrogen ice (Seligman & Laughlin 2020). Alternative explanations have invoked the presence of N 2 -and CO-driven activity Seligman et al 2021) or radiation pressure (Micheli et al 2018).…”

Section: Introductionmentioning

confidence: 99%

(523599) 2003 RM: The Asteroid that Wanted to be a Comet

et al. 2023

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We report a statistically significant detection of nongravitational acceleration on the subkilometer near-Earth asteroid (523599) 2003 RM. Due to its orbit, 2003 RM experiences favorable observing apparitions every 5 yr. Thus, since its discovery, 2003 RM has been extensively tracked with ground-based optical facilities in 2003, 2008, 2013, and 2018. We find that the observed plane-of-sky positions cannot be explained with a purely gravity-driven trajectory. Including a transverse nongravitational acceleration allows us to match all observational data, but its magnitude is inconsistent with perturbations typical of asteroids such as the Yarkovsky effect or solar radiation pressure. After ruling out that the orbital deviations are due to a close approach or collision with another asteroid, we hypothesize that this anomalous acceleration is caused by unseen cometary outgassing. A detailed search for evidence of cometary activity with archival and deep observations from the Panoramic Survey Telescope and Rapid Response System and the Very Large Telescope does not reveal any detectable dust production. However, the best-fitting H2O sublimation model allows for brightening due to activity consistent with the scatter of the data. We estimate the production rate required for H2O outgassing to power the acceleration and find that, assuming a diameter of 300 m, 2003 RM would require Q(H2O) ∼ 1023 molec s−1 at perihelion. We investigate the recent dynamical history of 2003 RM and find that the object most likely originated in the mid-to-outer main belt (∼86% probability) as opposed to from the Jupiter-family comet region (∼11% probability). Further observations, especially in the infrared, could shed light on the nature of this anomalous acceleration.

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“…Since 2017, the first two interlopers have provided close-up glimpses of extrasolar ejecta. The origin of 1I/'Oumuamua (Williams et al 2017;Meech et al 2017) has been fiercely debated, but each of the hypotheses on its bulk composition points toward previously unconsidered astrophysics in exoplanetary systems (Jewitt & Seligman 2022;Fitzsimmons et al 2023;Seligman & Moro-Martín 2023). Recently, Bergner & Seligman (2023) demonstrated that 'Oumuamua's properties were consistent with an amorphous water ice comet with radiolitically produced H 2 via galactic cosmic rays.…”

Section: Introductionmentioning

confidence: 99%

Interstellar Comets from Post-main-sequence Systems as Tracers of Extrasolar Oort Clouds

et al. 2023

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Interstellar small bodies are unique probes into the histories of exoplanetary systems. One hypothesized class of interlopers are “Jurads,” exocomets released into the Milky Way during the post-main-sequence as the thermally pulsing asymptotic giant branch (AGB) host stars lose mass. In this study, we assess the prospects for the Legacy Survey of Space and Time (LSST) to detect a Jurad and examine whether such an interloper would be observationally distinguishable from exocomets ejected during the (pre-)main-sequence. Using analytic and numerical methods, we estimate the fraction of exo–Oort Cloud objects that are released from 1–8 M ⊙ stars during post-main-sequence evolution. We quantify the extent to which small bodies are altered by the increased luminosity and stellar outflows during the AGB, finding that some Jurads may lack hypervolatiles and that stellar winds could deposit dust that covers the entire exocomet surface. Next, we construct models of the interstellar small body reservoir for various size–frequency distributions and examine the LSST’s ability to detect members of those hypothesized populations. Combining these analyses, we highlight the joint constraints that the LSST will place on power-law size–frequency distribution slopes, characteristic sizes, and the total mass sequestered in the minor planets of exo–Oort Clouds. Even with the LSST’s increased search volume compared to contemporary surveys, we find that detecting a Jurad is unlikely but not infeasible given the current understanding of (exo)planet formation.

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The Interstellar Interlopers

Cited by 11 publications

References 119 publications

A Bayesian Analysis of Technological Intelligence in Land and Oceans

A Bayesian Analysis of Technological Intelligence in Land and Oceans

(523599) 2003 RM: The Asteroid that Wanted to be a Comet

Interstellar Comets from Post-main-sequence Systems as Tracers of Extrasolar Oort Clouds

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