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Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres. I. High-Energy Irradiances (1-1700 Å)
We report on the results of the Sun in Time multiwavelength program (X-rays to UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and
The X-Ray Sun in Time: A Study of the Long-Term Evolution of Coronae of Solar-Type Stars
We have used the ASCA and ROSAT X-ray satellites to probe the coronae of a sample of nine solar-like G stars. These stars are all ostensibly single with ages ranging from 70 Myr to 9 Gyr and have
The distance to the Andromeda galaxy from eclipsing binaries
The cosmic distance scale largely depends on distance determinations to galaxies of the Local Group. In this sense, the Andromeda galaxy (M 31) is a key rung to better constrain the cosmic distance
Atmospheric Loss of Exoplanets Resulting from Stellar X-Ray and Extreme-Ultraviolet Heating
Past studies addressing the thermal atmospheric escape of hydrogen from hot Jupiters have been based on the planet's effective temperature, which, as we show here, is not physically relevant for loss
Intrinsic Properties of the Young Stellar Object SU Aurigae
Intensive long-term photometric Q1 observations of the archetypical young G2 IIIe stellar object SU Aurigae are analyzed to determine many of its photometric and physical properties. Combining nearly
Absolute Properties of the Low-Mass Eclipsing Binary CM Draconis
Spectroscopic and eclipsing binary systems offer the best means for determining accurate physical properties of stars, including their masses and radii. The data available for low-mass stars have
First Determination of the Distance and Fundamental Properties of an Eclipsing Binary in the Andromeda Galaxy
We present the first detailed spectroscopic and photometric analysis of an eclipsing binary in the Andromeda Galaxy (M31). This is a 19.3 mag semidetached system with late O and early B spectral type
The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present
Proxima b is a planet with a minimum mass of 1.3 MEarth orbiting within the habitable zone (HZ) of Proxima Centauri, a very low-mass, active star and the Sun's closest neighbor. Here we investigate a
The Distance to the Large Magellanic Cloud from the Eclipsing Binary HV 2274
The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the cosmic distance scale. We derive a distance to the LMC based on an analysis of ground-based photometry and
The distance to the M supergiant Betelgeuse is poorly known, with the Hipparcos parallax having a significant uncertainty. For detailed numerical studies of M supergiant atmospheres and winds,