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Astronomers have found more than a dozen planets transiting stars that are 10–40 million years old 1 , but younger transiting planets have remained elusive. The lack of such discoveries may be because planets have not fully formed at this age or because our view is blocked by the protoplanetary disk. However, we now know that many outer disks are warped or broken 2 ; provided the inner disk is depleted, transiting planets may thus be visible. Here we report observations of the transiting planet IRAS 04125+2902 b orbiting a 3-million-year-old, 0.7-solar-mass, pre-main-sequence star in the Taurus Molecular Cloud. The host star harbours a nearly face-on (30 degrees inclination) transitional disk 3 and a wide binary companion. The planet has a period of 8.83 days, a radius of 10.7 Earth radii (0.96 Jupiter radii) and a 95%-confidence upper limit on its mass of 90 Earth masses (0.3 Jupiter masses) from radial-velocity measurements, making it a possible precursor of the super-Earths and sub-Neptunes frequently found around main-sequence stars. The rotational broadening of the star and the orbit of the wide (4 arcseconds, 635 astronomical units) companion are both consistent with edge-on orientations. Thus, all components of the system are consistent with alignment except the outer disk; the origin of this misalignment is unclear. Observations of a 3-million-year-old pre-main-sequence star with a misaligned disk reveal a giant orbiting planet; the system is ideal for studying the early formation and migration of planets.

We describe the target selection procedure by which stars are selected for 2 minute and 20 s observations by TESS. We first list the technical requirements of the TESS instrument and ground systems processing that limit the total number of target slots. We then describe algorithms used by the TESS Payload Operation Center (POC) to merge candidate targets requested by the various TESS mission elements (the Target Selection Working Group, TESS Asteroseismic Science Consortium, and Guest Investigator office). Lastly, we summarize the properties of the observed TESS targets over the two-year primary TESS mission. We find that the POC target selection algorithm results in 2.1–3.4 times as many observed targets as target slots allocated for each mission element. We also find that the sky distribution of observed targets is different from the sky distributions of candidate targets due to technical constraints that require a relatively even distribution of targets across the TESS fields of view. We caution researchers exploring statistical analyses of TESS planet-host stars that the population of observed targets cannot be characterized by any simple set of criteria applied to the properties of the input Candidate Target Lists.

We have carried out an ALMA Cycle 2 survey of 15 confirmed or candidate low-mass (<0.2M⊙) members of the TW Hya Association (TWA) with the goal of detecting line emission from CO molecular gas and continuum emission from cold dust. Our targets have spectral types of M4-L0 and hence represent the extreme low end of the TWA's mass function. The survey has yielded a detection of 12CO(2–1) emission around TWA 34. This newly discovered ~10 Myr-old molecular gas disk lies just ~50pc from Earth.

We describe the target selection procedure by which stars are selected for 2 minute and 20 s observations by TESS. We first list the technical requirements of the TESS instrument and ground systems processing that limit the total number of target slots. We then describe algorithms used by the TESS Payload Operation Center (POC) to merge candidate targets requested by the various TESS mission elements (the Target Selection Working Group, TESS Asteroseismic Science Consortium, and Guest Investigator office). Lastly, we summarize the properties of the observed TESS targets over the two-year primary TESS mission. We find that the POC target selection algorithm results in 2.1–3.4 times as many observed targets as target slots allocated for each mission element. We also find that the sky distribution of observed targets is different from the sky distributions of candidate targets due to technical constraints that require a relatively even distribution of targets across the TESS fields of view. We caution researchers exploring statistical analyses of TESS planet-host stars that the population of observed targets cannot be characterized by any simple set of criteria applied to the properties of the input Candidate Target Lists.

This study focused on analyzing and comparing aerial and sediment palynological samples from two sites around the city of Bahía Blanca in order to relate the pollen spectra of the samples with the environments of origin and their possible use in a future forensic scenario. Pollen grains collected in three matrices were examined: surface sediment, sediment collected from footwear, and pollen grains retained on fabrics. The palynological information revealed a great similarity in composition between the different collection matrices at each site, and a significant difference between the different collection sites. The dominant pollen types varied according to the sampling environment and were associated with the vegetation of influence at each one. The results suggest that anemophilous pollinated species predominated at both sites, the pollen representation reflected the proximity of the emitting sources and was related to the local floristic composition. In addition, allochthonous pollen types were found, indicating regional and extra-regional influences on the pollen spectra. The present study indicates that pollen spectra are capable of establishing geographical associations between samples, clearly differentiating the study sites, and at the same time highlighting the usefulness of this discipline to link objects or individuals to forensic scenarios. Este estudio se enfocó en analizar y comparar muestras palinológicas aéreas y de sedimentos de dos sitios en los alrededores de la ciudad de Bahía Blanca con el fin de asociar los espectros polínicos de las muestras con los ambientes de procedencia y su posible utilización en un futuro escenario forense. Se examinaron los granos de polen recolectados en tres matrices: sedimento superficial, sedimento recolectado del calzado y granos de polen retenidos en telas. La información palinológica reveló una gran similitud en la composición entre las diferentes matrices de recolección en cada sitio, y una diferencia significativa entre los distintos sitios de recolección. Los tipos polínicos dominantes variaron según el ambiente de muestreo y se vincularon con la vegetación de influencia en cada uno. Los resultados sugieren que las especies de polinización anemófila predominaron en ambos sitios, la representación polínica reflejó la cercanía de las fuentes emisoras y se relacionó con la composición florística local. Además, se encontraron tipos polínicos alóctonos, lo que indica influencias regionales y extra-regionales en los espectros polínicos. El presente estudio indica que los espectros polínicos son capaces de establecer asociaciones geográficas entre las muestras, diferenciando claramente los sitios de estudio, y a su vez poniendo de manifiesto la utilidad de esta disciplina para vincular objetos o individuos con escenarios forenses.

This thesis gathers three separate, but related, topics to address the formation of low-mass objects including stars, brown dwarfs, and planets. We have discovered a new method to search for young stars using the ultraviolet GALEX all-sky imaging survey. We applied this method to carry out a search for young, low-mass stars in the TW Hydrae Association and Scorpius-Centaurus region and have identified 54 candidate young stars. Spectroscopic followup has shown lithium absorption in many of these candidates, confirming their youth. As a second project, we have searched in the infrared for the coolest brown dwarf companions to white dwarf stars with both ground- and space-based instruments. We reach sensitivities that allow us to detect companions with Teff ∼ 500 K or cooler in some cases, which is still a relatively unexplored (but quickly growing) temperature range for substellar objects. No substellar (or stellar) companions are detected, but we better constrain the properties of the recently discovered low temperature companion to WD 0806–661 (GJ 3483). A final aspect in this work is the study of disks in binary systems in order to characterize how likely planet formation occurs around multiple star systems. A sample of over 100 nearby debris disks is gathered and binaries are searched for via the literature and adaptive optics observations at Lick Observatory. We present a detailed case study of the circumbinary disk around V4046 Sagittarii, a 2.4-day spectroscopic binary. This system, observed with the Submillimeter Array at Mauna Kea Observatory, still retains a substantial gas-rich disk despite its relatively old age (∼ 12 Myr) Our work suggests that, while planets can form in binaries or multiple systems, compared to single stars the disks in which binary star planets form will be truncated or more readily cleared out by the influence of the companion star(s).

In an era where astronomical data is expanding at an unprecedented rate, the importance of data sharing and accessibility among astronomy archives cannot be overstated. Since the 1990s, an international partnership between the Space Telescope Science Institute (STScI), the European Space Astronomy Centre (ESAC), and the Canadian Astronomy Data Centre (CADC) has been focused on this endeavor, facilitating the exchange of data from the Hubble and James Webb Space Telescopes. We will present how this collaboration has evolved over time, highlighting key milestones and innovations in decision-making, communication, and technology. Additionally, we will discuss some of the challenges we have encountered and the strategies we employed to overcome them, offering insights that could benefit future archive collaborations.

Astronomers have found more than a dozen planets transiting 10-40 million year old stars, but even younger transiting planets have remained elusive. A possible reason for the lack of such discoveries is that newly formed planets are not yet in a configuration that would be recognized as a transiting planet or cannot exhibit transits because our view is blocked by a protoplanetary disk. However, we now know that many outer disks are warped; provided the inner disk is depleted, transiting planets may thus be visible. Here we report the observations of the transiting planet IRAS 04125+2902 b orbiting a 3 Myr, 0.7 M\\(_\\odot\\), pre-main sequence star in the Taurus Molecular Cloud. IRAS 04125+2902 hosts a nearly face-on (i \\(\\sim\\) 30\\(^\\circ\\)) transitional disk and a wide binary companion. The planet has a period of 8.83 days, a radius of 10.9 R\\(_\\oplus\\) (0.97R\\(_J\\)), and a 95%-confidence upper limit on its mass of 90M\\(_\\oplus\\) (0.3M\\(_J\\)) from radial velocity measurements, making it a possible precursor of the super-Earths and sub-Neptunes that are commonly found around main-sequence stars. The rotational broadening of the star and the orbit of the wide (4\", 635 AU) companion are both consistent with edge-on orientations. Thus, all components of the system appear to be aligned except the outer disk; the origin of this misalignment is unclear. Given the rare set of circumstances required to detect a transiting planet at ages when the disk is still present, IRAS 04125+2902 b likely provides a unique window into sub-Neptunes immediately following formation.