Search Publications
Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES
Bouchy, F.; Doyon, R.; Bonfils, X. +13 more
In an earlier campaign to characterize the mass of the transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited to exist in the system at 9 days. Further radial velocity follow-up with the CARMENES spectrograph visible channel revealed a much weaker signal at 9 days, which also appeared to vary chromatically …
Rotational modulation in TESS B stars
Handler, G.; Wade, G. A.; Cantiello, M. +6 more
Light curves and periodograms of 160 B stars observed by the Transiting Exoplanet Survey Satellite (TESS) space mission and 29 main-sequence B stars from Kepler and K2 were used to classify the variability type. There are 114 main-sequence B stars in the TESS sample, of which 45 are classified as possible rotational variables. This confirms previo…
Discovery of a Close-separation Binary Quasar at the Heart of a z ∼ 0.2 Merging Galaxy and Its Implications for Low-frequency Gravitational Waves
Strauss, Michael A.; Mingarelli, Chiara M. F.; Greene, Jenny E. +3 more
Supermassive black hole (SMBH) binaries with masses of ∼108-109 M ⊙ are expected to dominate the contribution to the as-yet undetected gravitational wave background (GWB) signal at the nanohertz frequencies accessible to pulsar timing arrays. We currently lack firm empirical constraints on the amplitude of the GWB …
HyDRA-H: Simultaneous Hybrid Retrieval of Exoplanetary Emission Spectra
Madhusudhan, Nikku; Gandhi, Siddharth; Hawker, George +1 more
High-resolution Doppler spectroscopy has been used to detect several chemical species in exoplanetary atmospheres. Such detections have traditionally relied on cross correlation of observed spectra against spectral model templates, an approach that is successful for detecting chemical species but not optimized for constraining abundances. Recent w…
The Onset and Growth of the 2018 Martian Global Dust Storm
Sánchez-Lavega, A.; Delcroix, M.; Hernández-Bernal, J. +1 more
We analyze the onset and initial expansion of the 2018 Martian Global Dust Storm (GDS 2018) using ground-based images in the visual range. This is the first case of a confirmed GDS initiating in the Northern Hemisphere. A dusty area extending about 1.4×105 km2 and centered at latitude +31.7°±1.8° and west longitude 18°±5°W in…
The spiral pattern rotation speed of the Galaxy and the corotation radius with Gaia DR2
Dias, W. S.; Monteiro, H.; Lépine, J. R. D. +1 more
In this work we revisit the issue of the rotation speed of the spiral arms and the location of the corotation radius of our Galaxy. This research was performed using homogeneous data set of young open clusters (age < 50 Myr) determined from Gaia Data Release 2 (DR2) data. The stellar astrometric membership was determined using proper motions an…
ACRONYM. III. Radial Velocities for 336 Candidate Young Low-mass Stars in the Solar Neighborhood, Including 77 Newly Confirmed Young Moving Group Members
Weinberger, Alycia J.; Kraus, Adam L.; Shkolnik, Evgenya L. +4 more
Young, low-mass stars in the solar neighborhood are vital for completing the mass function for nearby, young coeval groups, establishing a more complete census for evolutionary studies, and providing targets for direct-imaging exoplanet and/or disk studies. We present properties derived from high-resolution optical spectra for 336 candidate young …
Fine-scale Explosive Energy Release at Sites of Prospective Magnetic Flux Cancellation in the Core of the Solar Active Region Observed by Hi-C 2.1, IRIS, and SDO
Tiwari, Sanjiv K.; Golub, Leon; Winebarger, Amy R. +14 more
The second Hi-C flight (Hi-C 2.1) provided unprecedentedly high spatial and temporal resolution (∼250 km, 4.4 s) coronal EUV images of Fe IX/X emission at 172 Å of AR 12712 on 2018 May 29, during 18:56:21-19:01:56 UT. Three morphologically different types (I: dot-like; II: loop-like; III: surge/jet-like) of fine-scale sudden-brightening events (ti…
Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: Calibration and Methodology
Greene, Jenny E.; Beaton, Rachael L.; Carlsten, Scott G. +1 more
We explore the use of ground-based surface brightness fluctuation (SBF) measurements to constrain distances to nearby dwarf galaxies. Using archival CFHT Megacam imaging data for a sample of 28 nearby dwarfs, we demonstrate that reliable SBF measurements and distances accurate to 15% are possible even for very low surface brightness (µ …
Disentangling the spatial substructure of Cygnus OB2 from Gaia DR2
Lennon, D. J.; Herrero, A.; Wright, N. J. +2 more
For the first time, we have explored the spatial substructure of the Cygnus OB2 association using parallaxes from the recent second Gaia data release. We find significant line-of-sight substructure within the association, which we quantify using a parametrized model that reproduces the observed parallax distribution. This inference approach is nec…