Search Publications
Missions
Journals
Publication Years
Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692
Gies, Douglas R.; Lester, Kathryn V.; Monnier, John D. +18 more
We present the visual orbits of four spectroscopic binary stars, HD 61859, HD 89822, HD 109510, and HD 191692, using long baseline interferometry with the CHARA Array. We also obtained new radial velocities from echelle spectra using the APO 3.5 m, CTIO 1.5 m, and Fairborn Observatory 2.0 m telescopes. By combining the astrometric and spectroscopi…
The Helicity Sign of Flux Transfer Event Flux Ropes and Its Relationship to the Guide Field and Hall Physics in Magnetic Reconnection at the Magnetopause
Lavraud, B.; Génot, V.; Chen, Y. +13 more
Flux Transfer Events (FTEs) are transient magnetic flux ropes typically found at the Earth's magnetopause on the dayside. While it is known that FTEs are generated by magnetic reconnection, it remains unclear how the details of magnetic reconnection controls their properties. A recent study showed that the helicity sign of FTEs positively correlat…
Spectroscopic analysis of BPS CS 22940-0009: connecting evolved helium stars
Jeffery, C. S.; Woolf, V. M.; Snowdon, E. J. +1 more
BPS CS 22940-0009 is a helium-rich B-star that shares characteristics with both helium-rich B subdwarfs and extreme helium stars. The optical spectrum of BPS CS 22940-0009 has been analysed from SALT observations. The atmospheric parameters were found to be $T_{\rm eff} = 34\, 970 \pm 370$ K, $\log g/{\rm cm\, s^{-2}} = 4.79 \pm 0.17$, nH
First photometric and orbital period investigations of four W UMa-type eclipse binaries
Meng, Zi-Bin; Wang, Hong-Wei; Yu, Yun-Xia +2 more
We presented the first photometric and orbital period investigations for four W Ursae Majoris-type binaries: V473 And, V805 And, LQ Com, and EG CVn. The photometric solutions suggested that V805 And and LQ Com are two total-eclipse contact binaries, while V473 And and EG CVn are partial-eclipse ones. V473 And and LQ Com belong to the A-subtype con…
The Dawn-Dusk Tail Lobe Magnetotail Configuration and the Formation of Aurora Transpolar Arc
Angelopoulos, Vassilis; Wu, Leyuan; Mieth, Johannes +2 more
The magnetotail configuration includes a northern tail lobe, a southern tail lobe, and a plasma sheet when IMF directs southward, as a result of the Dungey cycle. However, it is little known about the magnetotail configuration for northward IMF (NIMF) conditions. Using in situ data and corresponding simulations, we show that the magnetotail forms …
Retrieving the transmission spectrum of HD 209458b using CHOCOLATE: a new chromatic Doppler tomography technique
Rebolo, R.; Pallé, E.; Zapatero Osorio, M. R. +29 more
Multiband photometric transit observations or low-resolution spectroscopy (spectro-photometry) are normally used to retrieve the broadband transmission spectra of transiting exoplanets in order to assess the chemical composition of their atmospheres. In this paper we present an alternative approach for recovering the broadband transmission spectra…
X-Rays in Cepheids: Identifying Low-mass Companions of Intermediate-mass Stars
Drake, Jeremy J.; Evans, Nancy Remage; Breuval, Louise +12 more
X-ray observations have been made of a sample of 20 classical Cepheids, including two new observations (Polaris and l Car) reported here. The occurrence of X-ray flux around the pulsation cycle is discussed. Three Cepheids are detected (δ Cep, β Dor, and Polaris). X-rays have also been detected from the low-mass F, G, and K companions of four Ceph…
Amplitudes of Solar Gravity Modes: A Review
Buldgen, G.; Belkacem, K.; Pinçon, C.
Solar gravity modes are considered the Rosetta Stone for probing and subsequently deciphering the physical properties of the solar inner-most layers. Recent claims of positive detection therefore shed some new light on the long-standing issue of estimating solar gravity mode amplitudes. In this article, our objective is to review the theoretical e…
Improved binary solution for the gamma-ray binary 1FGL J1018.6-5856
Monageng, I. M.; van Soelen, B.; Chernyakova, M. +4 more
The gamma-ray binary 1FGL J1018.6-5856 consists of an O6V((f)) type star and an unknown compact object, and shows orbitally modulated emission from radio to very high energy gamma rays. The X-ray light curve shows a maximum around the same phase as the GeV emission, but also a secondary maximum between phases ϕ = 0.2 and 0.6. A clear solution to t…
The effect of viewing angle on the Kennicutt-Schmidt relation of the local molecular clouds
Kainulainen, J.; Rezaei, Kh. S.; Spilker, A. +1 more
The Gaia data give us an unprecedented view to the three-dimensional (3D) structure of molecular clouds in the solar neighbourhood. We study how the projected areas and masses of clouds, and consequently the Kennicutt-Schmidt (KS) relation, depend on the viewing angle. We derive the probability distributions of the projected areas and masses for n…