Search Publications
Constraining the oblateness of transiting planets with photometry and spectroscopy
Serrano, L. M.; Barros, S. C. C.; Santos, N. C. +2 more
Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While planetary oblateness has mostly been probed by examining the subtle ingress and egress features in photometric transit light curves, we investigate the effect of oblateness on the spectroscopic Rossiter-McLaughlin (RM) signals. We found that a giant planet, wi…
Irregular changes in Hα emission line of V423 Aur observed by LAMOST Medium-Resolution Spectrographs
Wu, Hong; Hsia, Chih-Hao; Shi, Jian-Rong +8 more
We obtained seven spectra of the Be star V423 Aur on 2017 Dec. 5 using the LAMOST Medium-Resolution Spectrograph with exposures from 600 to 1200 seconds. These spectra show the irregular Hα emission line profile variations (LPVs). In the seven spectra, from the 4th to 7th, the left part of Hα profile even shows excess. However, no variation can be…
The spatial distribution of circumstellar material of the wind-fed system GX 301-2
Gou, Lijun; Liu, Jiren; Zheng, Xueying
The distribution of the circumstellar material in systems of supergiant X-ray binaries (SgXBs) is complex and not well probed observationally. We report a detailed study of the spatial distribution of the Fe K α-emitting material in the wind-fed system GX 301-2, by measuring the time delay between the Fe K α line and the hard X-ray continuum (7.8-…
KIC 12268220: A δ Scuti Pulsating Star and an Active Protohelium White Dwarf in an Eclipsing Binary System
Liu, Jifeng; Gao, Qing; Ren, Juanjuan +4 more
We present a photometric, spectroscopic, asteroseismic, and evolutionary analysis of the Algol-type eclipsing binary KIC 12268220. We find the O'Connell effect and anticorrelated eclipse timing variations in the Kepler light curve, revealing the presence of large starspots. Radial velocities and atmospheric parameters are obtained from ground-base…
Formation of a tiny flux rope in the center of an active region driven by magnetic flux emergence, convergence, and cancellation
Cao, Wenda; Chen, Yao; Zheng, Ruisheng +2 more
Aims: Flux ropes are generally believed to be core structures of solar eruptions that are significant for the space weather, but their formation mechanism remains intensely debated. We report on the formation of a tiny flux rope beneath clusters of active region loops on 2018 August 24.
Methods: Combining the high-quality multiwavelength…
NuSTAR Observations and Multiwavelength Modeling of the High-redshift BL Lacertae Object 4FGL J2146.5-1344
Ajello, M.; Kaur, A.; Hartmann, D. +3 more
High synchrotron peak (HSP; ${\nu }_{\mathrm{sy}}^{\mathrm{pk}}\gt {10}^{15}$ Hz) BL Lac objects are some of the most extreme accelerators in the universe. Those found at high redshifts (z > 1) challenge our understanding of blazar evolution models and are crucial for cosmological measurements of the extragalactic background light. In this pape…
VLA ammonia observations of L1287. Analysis of the Guitar core and two filaments
Palau, Aina; Rodríguez, Luis F.; Busquet, Gemma +6 more
Aims: In this paper, we study the dense gas of the molecular cloud LDN 1287 (L1287), which harbors a double FU Ori system, an energetic molecular outflow, and a still-forming cluster of deeply embedded low-mass young stellar objects that show a high level of fragmentation.
Methods: We present optical Hα and [SII], and VLA NH3 …
Reply to: On the signature of a 70-solar-mass black hole in LB-1
Soria, Roberto; Liu, Jifeng; Lu, Youjun +4 more
Radial velocity constraints on the long-period transiting planet Kepler-1625 b with CARMENES
Heller, René; Reiners, Ansgar; Zechmeister, Mathias +1 more
Context. The star Kepler-1625 recently attracted considerable attention when an analysis of the stellar photometric time series from the Kepler mission was interpreted as showing evidence of a large exomoon around the transiting Jupiter-sized planet candidate Kepler-1625 b. However, the mass of Kepler-1625 b has not been determined independently a…
The {}(\mathbf{7}) Be Abundance in Nova V5668 Sgr Is Consistent with the Theory
Chugai, N. N.; Kudryashov, A. D.
By now the resonance lines of the isotope ${}7$Be have been detected in five novae. The known estimates of the relative abundance of this isotope from the equivalent widths of ${}7$Be II and Ca II lines lead to the conclusion that the ${}7$Be abundance is considerably higher than the predictions of thermonuclear bu…