Results 71 to 80 of about 389,568 (229)

Wavelength-dependent Extinction and Grain Sizes in “Dippers”

The Astronomical Journal, 2023
We have examined internight variability of K2-discovered “dippers” that are not close to being viewed edge-on, as determined from previously reported ALMA images, using the SpeX spectrograph on NASA’s Infrared Telescope Facility.
Michael L. Sitko, Ray W. Russell, Zachary C. Long, Korash Assani, Monika Pikhartova, Ammar Bayyari, Carol A. Grady, Carey M. Lisse, Massimo Marengo, John P. Wisniewski, William C. Danchi   +10 more
doaj   +1 more source

JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against ...
L. R. Bedin, D. Nardiello, M. Salaris, M. Libralato, P. Bergeron, A. J. Burgasser, D. Apai, M. Griggio, M. Scalco, J. Anderson, R. Gerasimov, A. Bellini   +11 more
wiley   +1 more source

TW HYA ASSOCIATION MEMBERSHIP AND NEW WISE-DETECTED CIRCUMSTELLAR DISKS [PDF]

, 2012
We assess the current membership of the nearby, young TW Hydrae association and examine newly proposed members with the Wide-field Infrared Survey Explorer (WISE) to search for infrared excess indicative of circumstellar disks. Newly proposed members TWA
A. Schneider, C. Melis, I. Song
semanticscholar   +1 more source

The deep eclipses of RW Aur revisited by long‐term photometric and spectroscopic monitoring

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract RW Aurigae is a young stellar system containing a classical T Tauri star as the primary component. It shows deep, irregular dimmings, first detected in 2010. At the University Observatory Jena, we carried out optical follow‐up observations. We performed multiband (BVRI) photometry of the system with the Cassegrain‐Teleskop‐Kamera II and the ...
Oliver Lux, Markus Mugrauer, Richard Bischoff   +2 more
wiley   +1 more source

Secret of Longevity: Protoplanetary Disks as a Source of Gas in Debris Disks

The Astrophysical Journal
While protoplanetary disks (PPDs) are generally thought to disperse within several million years, recent observations have revealed gas in their older counterparts, debris disks.
Wataru Ooyama, Riouhei Nakatani, Takashi Hosokawa, Hiroto Mitani, Neal J. Turner   +4 more
doaj   +1 more source

FIRST DETECTION OF NEAR-INFRARED LINE EMISSION FROM ORGANICS IN YOUNG CIRCUMSTELLAR DISKS [PDF]

, 2012
We present an analysis of high-resolution spectroscopy of several bright T Tauri stars using the CRIRES spectrograph on the Very Large Telescope and NIRSPEC spectrograph on the Keck Telescope, revealing the first detections of emission from HCN and C2H2 ...
A. Mandell, J. Bast, E. V. van Dishoeck, G. Blake, C. Salyk, M. Mumma, G. Villanueva   +6 more
semanticscholar   +1 more source

Limitations of the modified blackbody fit method for determining molecular cloud properties

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract Achieving a comprehensive understanding of the star and planet formation process is one of the fundamental tasks of astrophysics, requiring detailed knowledge of the physical conditions during the different phases of this process. During the earliest stages, that is, concerning physical processes in molecular clouds and filaments, the column ...
Niko Zielinski, Sebastian Wolf
wiley   +1 more source

AC Her: Evidence of the First Polar Circumbinary Planet

The Astrophysical Journal Letters, 2023
We examine the geometry of the post–asymptotic giant branch (AGB) star binary AC Her and its circumbinary disk. We show that the observations describe a binary orbit that is perpendicular to the disk with an angular momentum vector that is within 9° of ...
Rebecca G. Martin, Stephen H. Lubow, David Vallet, Narsireddy Anugu, Douglas R. Gies   +4 more
doaj   +1 more source

Tracing large-scale structures in circumstellar disks with ALMA [PDF]

, 2012
Context. Planets are supposed to form in circumstellar disks. The additional 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. Aims. We perform a large-
J. P. Ruge, S. Wolf, A. Uribe, H. Klahr
semanticscholar   +1 more source

Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic O9.7 V star HD 54879 using rotational modulation of the Hα profile

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract The magnetic field in the O9.7 V star HD 54879 has been monitored for almost a decade. Spectropolarimetric observations reveal a rather strong mean longitudinal magnetic field that varies with a period of about 7.41 years. Observations in the Hα$$ \alpha $$ line show a variation with the same period, while the Hβ$$ \beta $$ line shows only ...
Manfred Küker, S. P. Järvinen, S. Hubrig, Ilya Ilyin, M. Schöller   +4 more
wiley   +1 more source