Search Publications
Lithium Enrichment Signatures of Planetary Engulfment Events in Evolved Stars
Ness, Melissa K.; Cantiello, Matteo; MacLeod, Morgan +1 more
Planetary engulfment events have long been proposed as a lithium (Li) enrichment mechanism contributing to the population of Li-rich giants (A(Li) ≥ 1.5 dex). Using MESA stellar models and A(Li) abundance measurements obtained by the GALAH survey, we calculate the strength and observability of the surface Li enrichment signature produced by the en…
A Complex Luminosity Function for the Anomalous Globular Clusters in NGC 1052-DF2 and NGC 1052-DF4
van Dokkum, Pieter; Shen, Zili; Danieli, Shany
NGC 1052-DF2 and NGC 1052-DF4 are ultradiffuse galaxies that have extremely low velocity dispersions, indicating that they have little or no dark matter. Both galaxies host anomalously luminous globular clusters (GCs), with a peak magnitude of their GC luminosity function (GCLF) that is ∼1.5 mag brighter than the near-universal value of MV
Planet Hunters TESS II: findings from the first two years of TESS
Aigrain, S.; Vaughan, S.; Barragán, O. +23 more
We present the results from the first two years of the Planet Hunters TESS (PHT) citizen science project, which identifies planet candidates in the TESS (Transiting Exoplanet Survey Satellite) data by engaging members of the general public. Over 22 000 citizen scientists from around the world visually inspected the first 26 sectors of TESS data in…
Stellar Rotation in the K2 Sample: Evidence for Modified Spin-down
Davenport, James R. A.; Angus, Ruth; Foreman-Mackey, Daniel +5 more
We analyze light curves of 284,834 unique K2 targets using a Gaussian process model with a quasi-periodic kernel function. By cross-matching K2 stars to observations from Gaia Data Release 2, we have identified 69,627 likely main-sequence stars. From these we select a subsample of 8977 stars on the main sequence with highly precise rotation period…
The Magellan-TESS Survey. I. Survey Description and Midsurvey Results
Butler, R. Paul; Vanderburg, Andrew; Latham, David W. +67 more
Kepler revealed that roughly one-third of Sunlike stars host planets orbiting within 100 days and between the size of Earth and Neptune. How do these planets form, what are they made of, and do they represent a continuous population or multiple populations? To help address these questions, we began the Magellan-TESS Survey (MTS), which uses Magell…
TESS Observations of the Luhman 16 AB Brown Dwarf System: Rotational Periods, Lightcurve Evolution, and Zonal Circulation
Apai, Dániel; Bedin, Luigi R.; Nardiello, Domenico
Brown dwarfs were recently found to display rotational modulations, commonly attributed to cloud cover of varying thickness, possibly modulated by planetary-scale waves. However, the long-term, continuous, high-precision monitoring data to test this hypothesis for more objects is lacking. By applying our novel photometric approach to Transiting Ex…
Eridanus IV: an Ultra-faint Dwarf Galaxy Candidate Discovered in the DECam Local Volume Exploration Survey
Zenteno, A.; James, D. J.; Kuropatkin, N. +30 more
We present the discovery of a candidate ultra-faint Milky-Way satellite, Eridanus IV (DELVE J0505-0931), detected in photometric data from the DECam Local Volume Exploration survey (DELVE). Eridanus IV is a faint (MV = - 4.7 ± 0.2), extended ( ${r}_{1/2}={75}_{-13}^{+16}\,\mathrm{pc}$ ), and elliptical (ϵ = 0.54 ± 0.1) system at a helio…
Prestellar grain-surface origins of deuterated methanol in comet 67P/Churyumov-Gerasimenko
De Keyser, Johan; van Dishoeck, Ewine F.; Drozdovskaya, Maria N. +6 more
Deuterated methanol is one of the most robust windows astrochemists have on the individual chemical reactions forming deuterium-bearing molecules and the physicochemical history of the regions where they reside. The first-time detection of mono- and di-deuterated methanol in a cometary coma is presented for comet 67P/Churyumov-Gerasimenko using Ro…
METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. II. Variations of Interstellar Depletions and Dust-to-gas Ratio within the LMC
Jenkins, Edward B.; Yanchulova Merica-Jones, Petia; Gordon, Karl D. +9 more
A key component of the baryon cycle in galaxies is the depletion of metals from the gas to the dust phase in the neutral interstellar medium (ISM). The METAL (Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud) program on the Hubble Space Telescope acquired UV spectra toward 32 sight lines in the half-solar metallicity LMC, fr…
Testing fundamental physics with astrophysical transients
Wu, Xue-Feng; Wei, Jun-Jie
Explosive astrophysical transients at cosmological distances can be used to place precision tests of the basic assumptions of relativity theory, such as Lorentz invariance, the photon zero-mass hypothesis, and the weak equivalence principle (WEP). Signatures of Lorentz invariance violations (LIV) include vacuum dispersion and vacuum birefringence.…