Related papers: Multi-wavelength observations of Proxima Centauri
Post-flare loops are loop-like plasmas observed during the decay phase of solar flares, and they are expected to exist for stellar flares. However, it is unclear how post-flare loops are observed in stellar flares' cases. To clarify…
The observational study of stars in the sub-millimetre regime has only rather recently begun and was made possible mainly by the Atacama Large Millimeter/submillimeter Array (ALMA). The emission mechanisms of this radiation from normal MS…
$\omega$ Centauri (NGC 5139) hosts hundreds of pulsating variable stars of different types, thus representing a treasure trove for studies of their corresponding period-luminosity (PL) relations. Our goal in this study is to obtain the PL…
We have conducted multi-epoch synthesis imaging of 2 and 3 millimeter (mm) continuum emission and near infrared K band 2.2 um imaging of a flare event in January 2003 that occurred on the young stellar object GMR-A which is suggested to be…
X-ray spectra of the late-type star AB Dor, obtained with the XMM-Newton satellite are analysed. AB Dor was particularly active during the observations. An emission measure reconstruction technique is employed to analyse flare and quiescent…
The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra…
We present a $\sim$130 ks observation of the prototypical wind-accreting, high-mass X-ray binary Vela X-1 collected with XMM-Newton at orbital phases between 0.12 and 0.28. A strong flare took place during the observation that allows us to…
On the 29 March 2014 NOAA active region (AR) 12017 produced an X1 flare which was simultaneously observed by an unprecedented number of observatories. We have investigated the pre-flare period of this flare from 14:00 UT until 19:00 UT…
We use more than a decade of radial velocity measurements for $\alpha$ Cen A, B, and Proxima Centauri from HARPS, CHIRON, and UVES to identify the $M \sin i$ and orbital periods of planets that could have been detected if they existed. At…
LkHA312 has been observed serendipitously with the ACIS-I detector on board Chandra with 26h continuous exposure. This H_alpha emission line star belongs to the star-forming region M78 (NGC2068). From the optical and NIR data, we show that…
Proxima Centauri is our nearest stellar neighbor and one of the most well-studied stars in the sky. In 2016, a planetary companion was detected through radial velocity measurements. Proxima Centauri b has a minimum mass of 1.3 Earth masses…
We have found that Proxima Centauri, the star closest to our Sun, will pass close to a pair of faint background stars in the next few years. Using Hubble Space Telescope (HST) images obtained in 2012 October, we determine that the passage…
We report on two XMM-Newton observations of the planetary host star HD189733. The system has a close in planet and it can potentially affect the coronal structure via interactions with the magnetosphere. We have obtained X-ray spectra and…
Flares close to the solar limb, where the footpoints are occulted, can reveal the spectrum and structure of the coronal loop-top source in X-rays. We aim at studying the properties of the corresponding energetic electrons near their…
Spatial information from stellar X-ray coronae can be inferred by use of scaling laws from the solar corona. This requires measurement of the physical parameters temperature and density. We concentrate on the newly available density…
We report multi-wavelength observations of four solar flares on 2014 July 07. We firstly select these flares according to the soft X-ray (SXR) and extreme ultraviolet (EUV) emissions recorded by the Extreme Ultraviolet Variability…
Observations of solar flares with RHESSI have shown X-ray sources traveling along flaring loops, from the corona down to the chromosphere and back up. The 28 November 2002 C1.1 flare, first observed with RHESSI by Sui et al. 2006 and…
In eclipsing X-ray binary systems, the direct X-ray emission is blocked by the companion star during the eclipse. We observe only reprocessed emission that contains clues about the environment of the compact object and its chemical…
I report on the high resolution spectra of the remarkable X9 solar flare of 2024 Oct 03 (SOL2024-10-03T12:08) and evaluate the extent to which nonthermal electron beams that generate dense chromospheric condensations can power very bright…
The Chinese Small Telescope ARray (CSTAR) carried out high-cadence time-series observations of 20.1 square degrees centered on the South Celestial Pole during the 2008, 2009 & 2010 winter seasons from Dome A in Antarctica. The…