Results 161 to 170 of about 6,211,798 (244)

Quiescent and Flaring States of Three Active Stars: V834 Tau, LQ Hya, and BY Dra

The Astrophysical Journal
We present a detailed X-ray study of the quiescent and flaring coronae of three active main-sequence K-type stars, V834 Tau, LQ Hya, and BY Dra, using XMM-Newton observations.
Gurpreet Singh, Jeewan C. Pandey, Subhajeet Karmakar   +2 more
doaj   +1 more source

Characterizing Superflares in HR 1099 Using Temporal and Spectral Analysis of XMM-Newton Observations

The Astronomical Journal
In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 hr, with e -folding rise and decay times in the range of 27–38 minutes and ...
Shweta Didel, Jeewan C. Pandey, A.K. Srivastava   +2 more
doaj   +1 more source

How rapidly do neutron stars spin at birth? Constaints from archival X-ray observations of extragalactic supernovae [PDF]

, 2008
Traditionally, studies aimed at inferring the distribution of birth periods of neutron stars are based on radio surveys. Here we propose an independent method to constrain the pulsar spin periods at birth based on their X-ray luminosities. In particular,
Perna, R., Soria, Roberto, Stella, L., Pooley, D., Perna, R, Pooley, D, Stella, L, SORIA, R   +7 more
core  

Ultraviolet Quasiperiodic Eruptions from Star–Disk Collisions in Galactic Nuclei

The Astrophysical Journal Letters
“Quasiperiodic eruptions” (QPE) are recurrent nuclear transients with periods of several hours to almost a day, which thus far have been detected exclusively in the X-ray band.
Itai Linial, Brian D. Metzger
doaj   +1 more source

Influence of stellar flare X-rays on the optical light curve

The Astrophysical Journal, 1977
D. J. Mullan, C. B. Tarter
openaire   +1 more source

Measuring the magnetic fields in the chromospheres of low-mass stars [PDF]

Nat Commun
Cang T, Petit P, Donati J, Tian H, Fu J, Li H, Bellotti S, Hu X, Ma X, Ariste AL, Xing K, Morin J, Lu H, Zong W.   +13 more
europepmc   +2 more sources

Resolved imaging confirms a radiation belt around an ultracool dwarf. [PDF]

Nature, 2023
Kao MM, Mioduszewski AJ, Villadsen J, Shkolnik EL.   +3 more
europepmc   +1 more source

Direct spectroscopic observation of matter falling onto a compact stellar object. [PDF]

Sci Adv
Rahin R, Ballhausen R, Islam N, Leutenegger MA, Behar E, Zamora D, Coley J, Hell N, Kallman T, Lorenz M, Pradhan P, Wilms J, Zainab A.   +12 more
europepmc   +1 more source

Revealing Flare Energetics and Dynamics with SDO EVE Solar Extreme Ultraviolet Spectral Irradiance Observations. [PDF]

Sol Phys
Woods TN, Chamberlin PC, Jones A, Mason JP, Qian L, Warren HP, Woodraska D, Borelli R, Eparvier FG, Gonzalez G.   +9 more
europepmc   +1 more source

Jets from a stellar-mass black hole are as relativistic as those from supermassive black holes. [PDF]

Nat Commun
Zhang X, Yu W, Carotenuto F, Fender R, Motta S, Bahramian A, Miller-Jones JCA, Russell TD, Corbel S, Woudt PA, Atri P, Knigge C, Sivakoff GR, Hughes AK, van den Eijnden J, Matthews JH, Baglio MC, Saikia P.   +17 more
europepmc   +1 more source