Results 41 to 50 of about 13,144 (210)

Large grains can grow in circumstellar discs [PDF]

Proceedings of the International Astronomical Union, 2013
AbstractWe perform coagulation & fragmentation simulations to understand grain growth in T Tauri & brown dwarf discs. We present a physically-motivated approach using a probability distribution function for the collision velocities and separating the deterministic & stochastic velocities.
Meru, Farzana, Galvagni, Marina, Olczak, Christoph, Garaud, Pascale   +3 more
openaire   +2 more sources

Are Giant Planets Forming Around HR 4796A? [PDF]

, 2003
We have obtained FUSE and HST STIS spectra of HR 4796A, a nearby 8 Myr old main sequence star that possesses a dusty circumstellar disk whose inclination has been constrained from high resolution near-infrared observations to be ~17 deg from edge-on.
Abgrall H., Augereau J. C., C. H. Chen, Holweger H., I. Kamp, Liseau R., Liseau R.   +6 more
core   +1 more source

CONSTRAINTS ON THE RADIAL VARIATION OF GRAIN GROWTH IN THE AS 209 CIRCUMSTELLAR DISK [PDF]

The Astrophysical Journal, 2012
7 pages, 5 figures, Accepted to ...
Pérez LM, Carpenter JM, Chandler CJ, Isella A, Andrews SM, Ricci L, Calvet N, Corder SA, Deller AT, Dullemond CP, Greaves JS, Harris RJ, Henning T, Kwon W, Lazio J, Linz H, Mundy LG, Sargent AI, Storm S, Testi L, Wilner DJ   +20 more
openaire   +3 more sources

Oceans, Lakes, and Stromatolites on Mars

Advances in Astronomy, Volume 2020, Issue 1, 2020., 2020
Billions of years ago, the Northern Hemisphere of Mars may have been covered by at least one ocean and thousands of lakes and rivers. These findings, based initially on telescopic observations and images by the Mariner and Viking missions, led investigators to hypothesize that stromatolite fashioning cyanobacteria may have proliferated in the surface ...
Rhawn G. Joseph, Olivier Planchon, N. S. Duxbury, K. Latif, G. J. Kidron, L. Consorti, R. A. Armstrong, C. Gibson, R. Schild, Michael Kueppers   +9 more
wiley   +1 more source

Observing dust settling and coagulation in circumstellar discs: Selected constraints from high resolution imaging

, 2010
Circumstellar discs are expected to be the nursery of planets. Grain growth within such discs is the first step in the planet formation process in the core-accretion gas-capture scenario.
Beckwith, Bjorkman, Blum, Boss, Brauer, Brown, Cuzzi, Draine, Draine, Duchêne, Dullemond, Dullemond, D’Alessio, Garaud, Guilloteau, Gullbring, Güttler, J. Sauter, Kamp, Kemper, Kessler-Silacci, Kim, Lada, Langkowski, Lucy, Mathis, McCabe, Meeus, Mie, Neuhäuser, Ormel, Ossenkopf, Pinte, Przygodda, Robitaille, S. Wolf, Sauter, Schegerer, Schegerer, Shakura, Sicilia-Aguilar, Sicilia-Aguilar, Simon, Stapelfeldt, Stapelfeldt, Thamm, Weidenschilling, Weidling, Weingartner, Wilking, Witt, Wolf, Wolf, Wolf, Wood   +54 more
core   +1 more source

Grain growth in newly discovered young eruptive stars

, 2020
FU Orionis-type stars are young stellar objects showing large outbursts due to highly enhanced accretion from the circumstellar disk onto the protostar.
Carmona, A., Chen, L., Green, J. D., Kóspál, Á., van Boekel, R., White, J. A., Ábrahám, P.   +6 more
core   +3 more sources

Discovery of Reflection Nebulosity Around Five Vega-like Stars [PDF]

, 2001
Coronagraphic optical observations of six Vega-like stars reveal reflection nebulosities, five of which were previously unknown. The nebulosities illuminated by HD 4881, HD 23362, HD 23680, HD 26676, and HD 49662 resemble that of the Pleiades, indicating
David C. Jewitt, Desert F.-X., Dunkin S. K., James P. Lloyd, James R. Graham, Kalas P., Paul Kalas, Plets P., Sfeir D. M., Steven V. W. Beckwith, Sylvester R. J., Sylvester R. J., Sylvester R. J., Welsh B. Y.   +13 more
core   +2 more sources

The Low Velocity Wind from the Circumstellar Matter Around the B9V Star sigma Herculis

, 2002
We have obtained FUSE spectra of sigma Her, a nearby binary system, with a main sequence primary, that has a Vega-like infrared excess. We observe absorption in the excited fine structure lines C II* at 1037 A, N II* at 1085 A, and N II** at 1086 A that ...
Abgrall H., Beust H., Bruhweiler F. C., C. H. Chen, Cote J., Fajardo-Acosta S. B., Figueras F., Grosbol P. J., M. Jura, Martin C., Vidal-Madjar A.   +10 more
core   +1 more source

Tracing large-scale structures in circumstellar disks with ALMA

, 2012
Planets are supposed to form in circumstellar disks. The gravitational potential of a planet perturbs the disk and leads to characteristic structures, i.e. spiral waves and gaps, in the disk's density profile.
Klahr, Hubert H., Ruge, Jan Philipp, Uribe, Ana L., Wolf, Sebastian   +3 more
core   +1 more source

Correlated Molybdenum, Ruthenium, and Barium Isotope Anomalies in Presolar Silicon Carbide Grains

The Astrophysical Journal
We have analyzed molybdenum, ruthenium, and barium isotopes simultaneously in 55 individual presolar silicon carbide (SiC) grains from the Murchison CM2 meteorite using the Chicago Instrument for Laser Ionization (or CHILI).
Thomas Stephan, Peter Hoppe, Andrew M. Davis, Julie M. Korsmeyer, Andrew Regula, Hannah E. Richards   +5 more
doaj   +1 more source