Search Publications
Evidence for Transparency and Clumps in the Circumbinary Ring of the T Tauri Star V582 Mon (KH 15D)
Winn, Joshua N.; Herbst, William; Newmark, Amanda +3 more
The binary T Tauri star V582 Mon (KH 15D) is surrounded by a tilted and nodally precessing ring of dusty material, which has caused periodic occultations of one or both stars over the last 50 years. Here, we present multi-color time-series photometry (VRIJHK) throughout the 2017/2018 observing season, when the ring was covering the entire orbit of…
Testing ΛCDM with Dwarf Galaxy Morphology
Xu, Weishuang Linda; Randall, Lisa
The leading tensions to the collisionless cold dark matter (CDM) paradigm are the "small-scale controversies," discrepancies between observations at the dwarf-galactic scale, and their simulational counterparts. In this work we consider methods to infer 3D morphological information on Local Group dwarf spheroidals and test the fitness of CDM+hydro…
Pleiades or Not? Resolving the Status of the Lithium-rich M Dwarfs HHJ 339 and HHJ 430
Oppenheimer, Rebecca; Aigrain, Suzanne; Hillenbrand, Lynne A. +7 more
Oppenheimer et al. discovered two M5 dwarfs in the Pleiades with nearly primordial lithium. These stars are not low enough in mass to represent the leading edge of the lithium depletion boundary at Pleiades age (∼125 Myr). A possible explanation for the enhanced lithium in these stars is that they are actually not members of the Pleiades but inste…
Which stars can see Earth as a transiting exoplanet?
Kaltenegger, L.; Pepper, J.
Transit observations have found the majority of exoplanets to date. Also spectroscopic observations of transits and eclipses are the most commonly used tool to characterize exoplanet atmospheres and will be used in the search for life. However, an exoplanet's orbit must be aligned with our line of sight to observe a transit. Here, we ask, from whi…
Two Quasi-periodic Oscillations in ESO 113-G010
Zhang, Peng; Yan, Jing-Zhi; Liu, Qing-Zhong
In the narrow-line Seyfert galaxy (NLS1) ESO 113-G010, two quasi-periodic oscillation (QPO) signals are detected in the XMM-Newton data collected in 2005 November. The XMM-Newton telescope has an exposure longer than 100 ks in the energy range of 0.3-10 keV. The data are analyzed using the Lomb-Scargle periodogram (LSP) and the weighted wavelet Z-…
Estimation of the Gould Belt Scale Height from T Tauri Type Stars in the Gaia DR2 Catalog
Bobylev, V. V.; Bajkova, A. T.
—We analyze the spatial and kinematic properties of a large sample of young T Tauri type stars in a 500 pc radius solar neighborhood, closely related to the Gould belt. The following parameters of the exponential density distribution have been determined: the average
Effective Opacity of the Intergalactic Medium from Galaxy Spectra Analysis
Chisholm, John; Prochaska, J. Xavier; Lee, Khee-Gan +1 more
We measure the effective opacity ( ${\tau }_{\mathrm{eff}}$ ) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2 ≲ z ≲ 3. Our spectra are taken from the COSMOS Lyα Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We…
Is the primary CoRoT target HD 43587 under a Maunder minimum phase?
Barbosa, R.; do Nascimento, J. -D.; Castro, M. +4 more
Context. One of the most enigmatic phenomena related to solar activity is the so-called Maunder minimum phase. It consists in the lowest sunspot count ever registered for the Sun and has not been confirmed for other stars to date. Since the spectroscopic observations of stellar activity at the Mount Wilson Observatory, the solar analog HD 43587 ha…
Absolute parameters of three southern eclipsing binaries: DQ Car, BK Ind, and V4396 Sgr
Erdem, Ahmet; Sürgit, Derya; Engelbrecht, Chris A. +1 more
We present combined photometric and spectroscopic analyses of the three southern eclipsing binary stars: DQ Car, BK Ind, and V4396 Sgr. Radial velocity curves of these three systems were obtained at the South African Astronomical Observatory, and their light curves from the available data bases and surveys were used for the analysis. 75 new times …
Relationship between Current Filaments and Turbulence During a Turbulent Reconnection
Yu, Y.; Chen, Z. Z.; Chen, F. +1 more
Both magnetic reconnection and turbulence can play crucial roles in space plasmas. The current layers, developing during magnetic reconnection, can collapse into various small-scale coherent structures, such as current filaments. These current filaments can significantly modulate the kinetic-scale turbulence. However, the quantitative correlation …