Search Publications

Planet interactions at a young age

Petralia, Antonino; Micela, Giuseppina; Cecchi-Pestellini, Cesare +2 more

X-ray irradiation of three planets around Hyades star K2 -136

Fernández Fernández, Jorge; Wheatley, Peter J.

We study the X-ray irradiation and likely photoevaporation of the three planets around the star K2-136. These are the Earth-sized K2-136 b, the mini-Neptune K2-136 c, and the super-Earth K2-136 d. XMM-Newton observations of the star indicate an X-ray luminosity of $(1.18\pm0.1)\times10^{28}$ erg s$^{-1}$ in the range 0.15 to 2.4 keV, resulting in …

Bright spectroscopic binaries: II. A study of five systems with orbital periods of P≲500 days

Jack, Dennis; Schröder, Klaus-Peter; Hernández Huerta, Missael Alejandro +1 more

We present a detailed analysis of five bright spectroscopic binary systems (HD 18665, HD 27131, HD 171852, HD 215550, and HD 217427) that have orbital periods of P≲500 days. We determined the complete set of orbital parameters using the toolkit RadVel by analyzing the observed radial velocity curves. To study the properties of the five systems, we…

X-ray views of our solar system

Branduardi-Raymont, Graziella

Identifying interesting planetary systems for future X-ray observations

Poppenhaeger, Katja; Foster, Grace

X-ray observations of star-planet systems are important to grow our understanding of exoplanets; these observation allow for studies of photoevaporation of the exoplanetary atmosphere, and in some cases even estimations of the size of the outer planetary atmosphere. The German-Russian eROSITA instrument onboard the SRG (Spectrum Roentgen Gamma) mi…

Stark broadening effect in hot DA white dwarfs: Ultraviolet lines of Fe V

Hamdi, Rafik; Ben Nessib, Nabil; Sahal-Bréchot, Sylvie +1 more

Stark widths and shifts have been calculated for 17 ultraviolet lines of Fe V of astrophysical interest. The calculations have been made using semiclassical perturbation approach. The work is motivated by the importance of ultraviolet lines for the study of hot white dwarf atmospheres specially for investigations of the variation of fine structure…

A list of guest‑star records in Korean history and their possible counterparts

An, Hongjun; Park, Jaegeun; Jeon, Junhyeok

We report on guest‑star events recorded in Korean history in the period between A.D. 154 and 1807. We search five books, namely Joseonwangjosillok, Seungjeongwonilgi, Jeungbomoonheonbigo, Goryeosa, and Samguksagi for "guest star" and find 37 events. Seventeen of the guest stars are almost certainly comets as identified previously and are not astro…

Studies of FCAPT UVBY photometry for the mCP stars HD 32966, HD 35298, HD 68292, HD 93226, HD 171247, HD 217833, HD 220147, and HD 223358

Adelman, Saul J.; Wittman, Todd; Dukes, Robert J., Jr.

We present differential Strömgren uvby observations from the Four College Automated Photometric Telescope (FCAPT) in Washington Camp, AZ of eight magnetic Chemically Peculiar (mCP) stars: HD 32966, HD 35298, HD 68292, HD 93226, HD 171247, HD 217833, HD 220147, and HD 223358. We use multiple period‑finding algorithms and incorporate data from the E…

Orbital Elements of visual binary stars with very short arcs: With application to double stars from the 1829 southern double star catalog of James Dunlop

Letchford, Roderick R.; White, Graeme L.; Brown, Carolyn J.

Binary double stars are those whose binding energies are less than zero. Obtaining binary star orbits from short arcs has been a long-standing problem in astrophysics. A method is presented and tested here, which addresses the problem by using space-based astrometry, photometry, and astrophysical data, together with historic measures, to generate …

On the lithium abundance of the visual binary components ξ Boo A ( G8V ) and ξ Boo B ( K5V )

Strassmeier, Klaus G.; Steffen, Matthias

A spectroscopic investigation of the lithium resonance doublet in ξ Boo A and ξ Boo B in terms of both abundance and isotopic ratio is presented. We obtained new R = 130,000 spectra with a signal‑to‑noise ratio (S/N) per pixel of up to 3200 using the 11.8 m LBT and PEPSI. From fits with synthetic line profiles based on 1D‑LTE MARCS model atmospher…