Search Publications
Photometric and Kinematic Study of the Open Clusters SAI 44 and SAI 45
Sharma, Saurabh; Joshi, Y. C.; Elsanhoury, W. H. +1 more
We carry out a detailed photometric and kinematic study of the poorly studied sparse open clusters SAI 44 and SAI 45 using ground-based BVRcIc data supplemented by archival data from Gaia eDR3 and Pan-STARRS. The stellar memberships are determined using a statistical method based on Gaia eDR3 kinematic data, and we found 204 …
The Source Locations of Major Flares and CMEs in Emerging Active Regions
Wang, Yuming; Liu, Lijuan; Cui, Jun +1 more
Major flares and coronal mass ejections (CMEs) tend to originate from compact polarity inversion lines (PILs) in solar active regions (ARs). Recently, a scenario named "collisional shearing" was proposed by Chintzoglou et al. to explain the phenomenon, which suggests that the collision between different emerging bipoles is able to form a compact P…
AlFoCS + F3D - II. Unexpectedly low gas-to-dust ratios in the Fornax galaxy cluster
De Looze, Ilse; Baes, Maarten; Bendo, George J. +14 more
We combine observations from Atacama Large Millimeter/submillimeter Array (ALMA), Australia Telescope Compact Array, Multi Unit Spectroscopic Explorer (MUSE), and Herschel to study gas-to-dust ratios in 15 Fornax cluster galaxies detected in the FIR/sub-mm by Herschel and observed by ALMA as part of the ALMA Fornax Cluster Survey. The sample spans…
APOGEE-2S Discovery of Light- and Heavy-element Abundance Correlations in the Bulge Globular Cluster NGC 6380
Cunha, Katia; Smith, Verne V.; Majewski, Steven R. +11 more
We derive abundance ratios for nine stars in the relatively high-metallicity bulge globular cluster NGC 6380. We find a mean cluster metallicity between [Fe/H] = -0.80 and -0.73, with no clear evidence for a variation in iron abundances beyond the observational errors. Stars with strongly enhanced [N/Fe] abundance ratios populate the cluster and a…
Mrk 1239: a Type-2 Counterpart of Narrow-line Seyfert-1?
Zhou, Hongyan; Ji, Tuo; Shi, Xiheng +10 more
We present new spectrophotometric and spectropolarimetric observations of Mrk 1239, one of the 8 prototypes that defines type-1 narrow-line Seyfert galaxies (NLS1s). Unlike the other typical NLS1s though, a high degree of polarization (P ∼ 5.6%) and red optical-IR (g-W4 = 12.35) colors suggest that Mrk 1239 is more similar to type-2 act…
Looking into the cradle of the grave: J22564-5910, a potential young post-merger hot subdwarf
Uzundag, Murat; Pelisoli, Ingrid; Bobrick, Alexey +10 more
Context. We present the discovery of J22564-5910, a new type of hot subdwarf (sdB) which shows evidence of gas present in the system and it has shallow, multi-peaked hydrogen and helium lines which vary in shape over time. All observational evidence points towards J22564-5910 being observed very shortly after the merger phase that formed it.
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The White Dwarfs of the Old, Solar-metallicity Open Star Cluster Messier 67: Properties and Progenitors
Kilic, Mukremin; Bolte, Michael; Canton, Paul A. +1 more
The old, solar-metallicity open cluster Messier 67 has long been considered a lynchpin in the study and understanding of the structure and evolution of solar-type stars. The same is arguably true for stellar remnants; the white dwarf population of M67 provides crucial observational data for understanding and interpreting white dwarf populations an…
K2-138 g: Spitzer Spots a Sixth Planet for the Citizen Science System
Kristiansen, Martti H.; Barclay, Thomas; Gorjian, Varoujan +10 more
K2 greatly extended Kepler's ability to find new planets, but it was typically limited to identifying transiting planets with orbital periods below 40 days. While analyzing K2 data through the Exoplanet Explorers project, citizen scientists helped discover one super-Earth and four sub-Neptune sized planets in the relatively bright (V = 12.21, K = …
Life after eruption VIII: The orbital periods of novae
Vogt, N.; Zorotovic, M.; Schreiber, M. R. +5 more
The impact of nova eruptions on the long-term evolution of Cataclysmic Variables (CVs) is one of the least understood and intensively discussed topics in the field. A crucial ingredient to improve with this would be to establish a large sample of post-novae with known properties, starting with the most easily accessible one, the orbital period. He…
TOI-954 b and K2-329 b: Short-period Saturn-mass Planets that Test whether Irradiation Leads to Inflation
Henning, Thomas; Vanderburg, Andrew; Bieryla, Allyson +70 more
We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of…