Nature Astronomy

Journal: Nature Astronomy

Abbreviation

Nat Astron

Publisher

Nature

ISSN

2397-3366

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Publications 1 - 10 of 42

Quantitative evaluation of gender bias in astronomical publications from citation counts
Caplar, Neven; Tacchella, Sandro; Birrer, Simon (2017)
Nature Astronomy
Numerous studies across different research fields have shown that both male and female referees consistently give higher scores to work done by men than to identical work done by women(1-3). In addition, women are under-represented in prestigious publications and authorship positions(4,5) and women receive similar to 10% fewer citations(6,7). In astronomy, similar biases have been measured in conference participation(8,9) and success rates for telescope proposals(10,11). Even though the number of doctorate degrees awarded to women is constantly increasing, women still tend to be under-represented in faculty positions(12). Spurred by these findings, we measure the role of gender in the number of citations that papers receive in astronomy. To account for the fact that the properties of papers written by men and women differ intrinsically, we use a random forest algorithm to control for the non-gender-specific properties of these papers. Here we show that papers authored by women receive 10.4 +/- 0.9% fewer citations than would be expected if the papers with the same non-gender-specific properties were written by men.
A new class of flares from accreting supermassive black holes
Trakhtenbrot, Benny; Arcavi, Iair; Ricci, Claudio; et al. (2019)
Nature Astronomy
Accreting supermassive black holes (SMBHs) can exhibit variable emission across the electromagnetic spectrum and over a broad range of timescales. The variability of active galactic nuclei (AGNs) in the ultraviolet and optical is usually at the few tens of per cent level over timescales of hours to weeks. Recently, rare, more dramatic changes to the emission from accreting SMBHs have been observed, including tidal disruption events, ‘changing look’ AGNs and other extreme variability objects. The physics behind the ‘re-ignition’, enhancement and ‘shut-down’ of accretion onto SMBHs is not entirely understood. Here we present a rapid increase in ultraviolet–optical emission in the centre of a nearby galaxy, marking the onset of sudden increased accretion onto a SMBH. The optical spectrum of this flare, dubbed AT 2017bgt, exhibits a mix of emission features. Some are typical of luminous, unobscured AGNs, but others are likely driven by Bowen fluorescence—robustly linked here with high-velocity gas in the vicinity of the accreting SMBH. The spectral features and increased ultraviolet flux show little evolution over a period of at least 14 months. This disfavours the tidal disruption of a star as their origin, and instead suggests a longer-term event of intensified accretion. Together with two other recently reported events with similar properties, we define a new class of SMBH-related flares. This has important implications for the classification of different types of enhanced accretion onto SMBHs.
Concerning the possible exomoons around Kepler-1625 b and Kepler-1708 b
Kipping, David; Teachey, Alex; Yahalomi, Daniel A.; et al. (2025)
Nature Astronomy
Seismic constraints from a Mars impact experiment using InSight and Perseverance
Fernando, Benjamin; Wójcicka, Natalia; Maguire, Ross; et al. (2022)
Nature Astronomy
NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed(1,2) and uncrewed(3,4) spacecraft, and on the Moon during the Apollo eras(5), but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance's entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance-amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy).
An estimate of the impact rate on Mars from statistics of very-high-frequency marsquakes
Zenhäusern, Géraldine; Wójcicka, Natalia; Stähler, Simon Christian; et al. (2024)
Nature Astronomy
The number density of impact craters on a planetary surface is used to determine its age, which requires a model for the production rate of craters of different sizes. On Mars, however, estimates of the production rate of small craters (<60 m) from orbital imagery and from extrapolation of lunar impact data do not match. Here we provide a new independent estimate of the impact rate by analysing the seismic events recorded by the seismometer onboard NASA's InSight lander. Some previously confirmed seismically detected impacts are part of a larger class of marsquakes (very high frequency, VF). Although a non-impact origin cannot be definitively excluded for each VF event, we show that the VF class as a whole is plausibly caused by meteorite impacts. We use an empirical scaling relationship to convert between seismic moment and crater diameter. Applying area and time corrections to derive a global impact rate, we find that 280-360 craters >8 m diameter are formed globally per year, consistent with previously published chronology model rates and above the rates derived from freshly imaged craters. Our work shows that seismology is an effective tool for determining meteoroid impact rates and complements other methods such as orbital imaging.
Tectonics of Cerberus Fossae unveiled by marsquakes
Stähler, Simon Christian; Mittelholz, Anna; Perrin, Clément; et al. (2022)
Nature Astronomy
The InSight mission has measured the seismicity of Mars since February 2019 and has enabled the investigation of tectonics on the surface of another planet for the first time. Its dataset shows that most of the widely distributed surface faults are not seismically active, and that seismicity is mostly originating from a single population of tectonic structures, the Cerberus Fossae. We show that the spectral character of deeper low-frequency marsquakes suggests a structurally weak, potentially warm source region consistent with recent magmatic activity at depths of 30–50 km. We further show that high-frequency marsquakes occur distributed along the Cerberus Fossae, in the brittle, shallow part, potentially in fault planes associated with the graben flanks. Together, these quakes release an annual seismic moment of 1.4–5.6 × 1015 N m yr−1 or at least half the seismicity of the entire planet. Our findings confirm that the Cerberus Fossae represents a unique tectonic setting shaped by current day magmatic processes and locally elevated heat flow.
Cosmic dust may have driven the geochemical origins of life on Earth
Walton, Craig R.; Schönbächler, Maria (2024)
Nature Astronomy
Cosmic dust contains all the elements needed for life but has previously been considered too rare to have acted as a 'fertilizer' for prebiotic chemistry. Now, using a combination of astrophysical and geological models, it is revealed that cosmic dust could have gently accumulated on the surface of early Earth in sufficient quantities to promote the chemical reactions that led to first life.
The dissipation of the solar nebula constrained by impacts and core cooling in planetesimals
Hunt, Alison; Theis, Karen J.; Rehkämper, Mark; et al. (2022)
Nature Astronomy
Rapid cooling of planetesimal cores has been inferred for several iron meteorite parent bodies on the basis of metallographic cooling rates, and linked to the loss of their insulating mantles during impacts. However, the timing of these disruptive events is poorly constrained. Here, we used the short-lived 107Pd–107Ag decay system to date rapid core cooling by determining Pd–Ag ages for iron meteorites. We show that closure times for the iron meteorites equate to cooling in the time frame ~7.8–11.7 Myr after calcium–aluminium-rich inclusion formation, and that they indicate that an energetic inner Solar System persisted at this time. This probably results from the dissipation of gas in the protoplanetary disk, after which the damping effect of gas drag ceases. An early giant planet instability between 5 and 14 Myr after calcium–aluminium-rich inclusion formation could have reinforced this effect. This correlates well with the timing of impacts recorded by the Pd–Ag system for iron meteorites.
A mature quasar at cosmic dawn revealed by JWST rest-frame infrared spectroscopy
Bosman, Sarah E.I.; Álvarez-Márquez, Javier; Colina, Luis; et al. (2024)
Nature Astronomy
The rapid assembly of the frst supermassive black holes is an enduring mystery. Until now, it was not known whether quasar ‘feeding’ structures (the ‘hot torus’) could assemble as fast as the smaller-scale quasar structures. We present JWST/MRS (rest-frame infrared) spectroscopic observations of the quasar J1120+0641 at z = 7.0848 (well within the epoch of reionization). The hot torus dust was clearly detected at λrest ≃ 1.3 μm, with a black-body temperature of Tdust = 1,413.5+5.7 −7.4 K, slightly elevated compared to similarly luminous quasars at lower redshifts. Importantly, the supermassive black hole mass of J1120+0641 based on the Hα line (accessible only with JWST), MBH = 1.52 ± 0.17 × 109 M⊙, is in good agreement with previous ground-based rest-frame ultraviolet Mg ii measurements. Comparing the ratios of the Hα, Paα and Paβ emission lines to predictions from a simple one-phase Cloudy model, we fnd that they are consistent with originating from a common broad-line region with physical parameters that are consistent with lower-redshift quasars. Together, this implies that J1120+0641’s accretion structures must have assembled very quickly, as they appear fully ‘mature’ less than 760 Myr after the Big Bang.
The rapid formation of macromolecules in irradiated ice of protoplanetary disk dust traps
Ligterink, Niels F.W.; Pinilla, Paola; van der Marel, Nienke; et al. (2024)
Nature Astronomy
Organic macromolecular matter is the dominant carrier of volatile elements such as carbon, nitrogen and noble gases in chondrites—the rocky building blocks from which Earth formed. How this macromolecular substance formed in space is unclear. Here we show that its formation could be associated with the presence of dust traps, which are prominent mechanisms for forming planetesimals in planet-forming disks. We demonstrate the existence of heavily irradiated zones in dust traps, where small frozen molecules that coat large quantities of microscopic dust grains could be rapidly converted into macromolecular matter by receiving radiation doses of up to several tens of electronvolts per molecule per year. This allows for the transformation of simple molecules into complex macromolecular matter within several decades. Up to roughly 4% of the total disk ice reservoir can be processed this way and subsequently incorporated into the protoplanetary disk midplane where planetesimals form. This finding shows that planetesimal formation and the production of organic macromolecular matter, which provides the essential elemental building blocks for life, might be linked.

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