Search Publications
Explosive nucleosynthesis of a metal-deficient star as the source of a distinct odd-even effect in the solar twin HIP 11915
Meléndez, Jorge; Karakas, Amanda I.; Asplund, Martin +2 more
The abundance patterns observed in the Sun and in metal-poor stars show a clear odd-even effect. An important question is whether the odd-even effect in solar-metallicity stars is similar to the Sun, or if there are variations that can tell us about different chemical enrichment histories. In this work, we report for the first time observational e…
Enhanced Super-Rotation Before and During the 2018 Martian Global Dust Storm
Fedorova, Anna A.; Holmes, James A.; Lewis, Stephen R. +3 more
Super-rotation affects—and is affected by—the distribution of dust in the martian atmosphere. We modeled this interaction during the 2018 global dust storm (GDS) of Mars Year 34 using data assimilation. Super-rotation increased by a factor of two at the peak of the GDS, as compared to the same period in the previous year which did not feature a GD…
Machine Learning the Sixth Dimension: Stellar Radial Velocities from 5D Phase-space Correlations
Lisanti, Mariangela; Cohen, Timothy; Dropulic, Adriana +3 more
The Gaia satellite will observe the positions and velocities of over a billion Milky Way stars. In the early data releases, the majority of observed stars do not have complete 6D phase-space information. In this Letter, we demonstrate the ability to infer the missing line-of-sight velocities until more spectroscopic observations become available. …
New X-ray detections of known Wolf-Rayet stars
Nazé, Yaël; Gosset, Eric; Marechal, Quentin
Using XMM-Newton, we undertook a dedicated project to search for X-ray bright wind-wind collisions in 18 WR+OB systems. We complemented these observations with Swift and Chandra data sets, allowing for the study of two additional systems. We also improved the ephemerides, for these systems displaying photometric changes, using TESS, Kepler, and AS…
Long-term X-ray evolution of SDSS J134244.4+053056.1. A more than 18 year-old, long-lived IMBH-TDE candidate
Shu, X. W.; Wang, T. G.; He, J. S. +5 more
SDSS J134244.4+053056 is a tidal disruption event candidate with strong temporal coronal line emitters and a long fading, mid-infrared dust echo. We present detailed analyses of X-ray emission from a Swift/XRT observation in 2009 and the most recent XMM-Newton/pn observation in 2020. The two spectra can be modeled with hard and soft components. Wh…
AzTEC survey of the central molecular zone: data reduction, analysis, and preliminary results
Zavala, Jorge A.; Gutermuth, Robert A.; Yun, Min S. +14 more
We present a large-scale survey of the central molecular zone (CMZ) of our Galaxy, as well as a monitoring program of Sgr A*, with the AzTEC/Large Millimeter Telescope in the 1.1 mm continuum. Our 1.1 mm map covers the main body of the CMZ over a field of 1.6 × 1.1 deg2 with an angular resolution of 10.5 arcsec and a depth of 15 mJy bea…
Knowledge Inventory of Foundational Data Products in Planetary Science
Beyer, Ross A.; Laura, Jason R.
Some of the key components of any Planetary Spatial Data Infrastructure (PDSI) are the data products that end-users wish to discover, access, and interrogate. One precursor to the implementation of a PSDI is a knowledge inventory that catalogs what products are available, from which data producers, and at what initially understood data qualities. …
IRIS observations of chromospheric heating by acoustic waves in solar quiet and active regions
Heinzel, P.; Liu, W.; Švanda, M. +3 more
Aims: To study the heating of solar chromospheric magnetic and nonmagnetic regions by acoustic and magnetoacoustic waves, the deposited acoustic-energy flux derived from observations of strong chromospheric lines is compared with the total integrated radiative losses.
Methods: A set of 23 quiet-Sun and weak-plage regions were observed in…
Fractal dimension of optical cirrus in Stripe82
Gontcharov, George A.; Mosenkov, Aleksandr V.; Román, Javier +4 more
The geometric characteristics of dust clouds provide important information on the physical processes that structure such clouds. One of such characteristics is the 2D fractal dimension D of a cloud projected on to the sky plane. In previous studies, which were mostly based on infrared (IR) data, the fractal dimension of individual clouds was found…
Hubble Space Telescope Observations of the Old Pulsar PSR J0108-1431
Pavlov, George G.; Mignani, Roberto P.; Abramkin, Vadim +1 more
We present results of optical-UV observations of the 200 Myr old rotation-powered radio pulsar J0108-1431 with the Hubble Space Telescope. We found a putative candidate for the far-UV (FUV) pulsar counterpart, with the flux density fν = 9.0 ± 3.2 nJy at λ = 1528 Å. The pulsar was not detected, however, at longer wavelengths, with 3σ upp…