Results 21 to 30 of about 15,327 (291)

Exoplanet transit photometry for stellar activity and exomoon research

, 2021
Photometry underlies important discoveries in observational astronomy, from the detection of stellar magnetic phenomena unveiling dynamic dynamo processes to the much sought-after identification of exomoons.
Zaleski, Shelley M.
core   +1 more source

Analysis of Solar-like X-class Flare on Wolf 359 Observed Simultaneously with TESS and XMM-Newton

The Astrophysical Journal, 2023
We present an analysis of a flare on the Wolf 359 star based on simultaneous observations of Transiting Exoplanet Survey Satellite and XMM-Newton. A stellar flare with energy comparable to an X-class solar flare is analyzed on this star for the first ...
M. Pietras, R. Falewicz, M. Siarkowski, A. Kepa, K. Bicz, P. Preś   +5 more
doaj   +1 more source

Disentangling planetary orbits from stellar activity in radial-velocity surveys [PDF]

, 2013
The majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now ...
Segransan, Damien, Pollacco, Don, Fares, R, Pollacco, D, Queloz, D., Haywood, R.D., Pollacco, D., Gillon, M, Gillon, M., Barros, SCC, Lanza, AF, Pepe, F., Cameron, A. Collier, Hatzes, A., Ségransan, D., Lovis, C, Lovis, Christophe, Moutou, C, Barros, S. C. C., Santerne, A., Unruh, Y., Haywood, R. D., Unruh, Y, Fares, R., Segransan, D, Moutou, C., Deleuil, M., Barros, S.C.C., Cameron, AC, Lanza, A.F., Pepe, F, Deleuil, M, Haywood, RD, Gillon, Michaël, Pepe, Francesco Alfonso, Santerne, A, Queloz, Didier, Lovis, C., Cameron, A.C., Hatzes, A, Lanza, A. F., Queloz, D   +41 more
core   +1 more source

Stellar activity [PDF]

Symposium - International Astronomical Union, 1986
We have been monitoring the CaII H and K emission in late-type giant stars using the Mt Wilson 60-inch telescope. It is a continuation of work that Olin Wilson began almost 20 years ago. As a result not only have starspot cycles been detected (equivalent to the solar sunspot cycle), but rotation periods have now been measured.
openaire   +1 more source

Stellar Chromospheric Variability

, 2021
Cool stars with convective envelopes of spectral types F and later tend to exhibit magnetic activity throughout their atmospheres. The presence of strong and variable magnetic fields is evidenced by photospheric starspots, chromospheric plages and ...
Richard de Grijs, Devika Kamath
core   +1 more source

STELLAR ACTIVITY IN THE BROADBAND ULTRAVIOLET [PDF]

The Astronomical Journal, 2011
The completion of the GALEX All-Sky Survey in the ultraviolet allows activity measurements to be acquired for many more stars than is possible with the limited sensitivity of ROSAT or the limited sky coverage of Chandra, XMM, or spectroscopic surveys for line emission in the optical or ultraviolet.
Findeisen, K., Hillenbrand, L., Soderblom, D.   +2 more
openaire   +3 more sources

Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey

The Astrophysical Journal Supplement Series, 2022
Stellar parameters and magnetic activity are important for the understanding of stellar physics and dynamo theory. We have used LAMOST spectroscopic surveys to study stellar parameters and magnetic activity properties of TESS objects.
Li-yun Zhang, Tianhao Su, Prabhakar Misra, Xianming L. Han, Gang Meng, Qingfeng Pi, Jiawei Yang   +6 more
doaj   +1 more source

How Magnetic Activity Alters What We Learn from Stellar Spectra [PDF]

, 2020
Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar spectra, varying during the activity cycle. This also influences the information that we derive through spectroscopic analysis.
Bedell, Megan, Yana Galarza, Jhon J., Megan Bedell, Casey, Andrew R., Lorenzo Spina, Jorge Meléndez, Martina Baratella, Andrew R. Casey, DESIDERA, Silvano, CASALI, GIADA, Jhon J. Yana Galarza, Giada Casali, SPINA, LORENZO, D'ORAZI, VALENTINA, Thomas Nordlander, Amanda I. Karakas, Silvano Desidera, Karakas, Amanda I., Meléndez, Jorge, Nordlander, Thomas, Baratella, Martina, Valentina D’Orazi   +21 more
core   +2 more sources

Stellar Activity Cycles

Space Science Reviews, 2023
AbstractThe magnetic field of the Sun is generated by internal dynamo process with a cyclic period of 11 years or a 22 year magnetic cycle. The signatures of the Sun’s magnetic cycle are observed in the different layers of its atmosphere and in its internal layers.
Jeffers, Sandra V., Kiefer, Rene, Metcalfe, Travis S.   +2 more
openaire   +2 more sources

Stellar populations in active galaxies [PDF]

Proceedings of the International Astronomical Union, 2004
To appear in "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", T. Storchi Bergmann, L.C. Ho & H.R. Schmitt, eds., Proc IAU Symp 222 (Cambridge University Press)
openaire   +2 more sources