Results 31 to 40 of about 335 (184)

Whither or Wither the Sulfur Anomaly in Planetary Nebulae?

The Astrophysical Journal Letters
We present a thorough investigation of the long-standing sulfur anomaly enigma. Our analysis uses chemical abundances from the most extensive data set available for 126 planetary nebulae (PNs) with improved accuracy and reduced uncertainties from a 10° ×
Shuyu Tan, Quentin A. Parker
doaj   +1 more source

The Properties of Planetary Nebulae Nuclei: Stellar Winds [PDF]

Symposium - International Astronomical Union, 1993
We present IUE observations of some nuclei of Planetary Nebulae. From these data we derive the stellar photospheric parameters (Teff Lbol, log g), and the wind characteristics (velocity, mass loss rate). Teff, R∗, Lbol are derived from UV low resolution spectra, combining optical and radio data, from Bianchi (1988) or from new IUE data, with the same ...
L. Bianchi, G. De Francesco
openaire   +1 more source

From Flybys to Sample Return: A Review of Space Probes and Robotic Sampling Technologies for Small Bodies

Journal of Field Robotics, EarlyView.
ABSTRACT As a crucial puzzle piece of deep space exploration, exploring small bodies can provide significant scientific insights and valuable mineral resources. Unlike missions to the Moon and Mars, small‐body missions pose distinct technical challenges, including communication delays, weak gravity, and uncertain environments. This paper reviews a full
Xin Zhang, Hao Zhou, Dalin Zhou, Zhaojie Ju   +3 more
wiley   +1 more source

Imaging polarimetry of planetary and proto-planetary nebulae [PDF]

, 1997
Optical imaging polarimetry has been performed on a small sample of objects which are associated with that stage of stellar evolution occurring between the Asymptotic Giant Branch and full Planetary Nebula. Three such systems are considered, specifically,
Bowlzer, S.L., Bowlzer, S. L.
core  

The 30 micron emission band in carbon-rich pre-planetary nebulae [PDF]

, 1995
The 16-48 μm spectra of five carbon-rich post-AGB objects (pre-planetary nebulae, PPNs) known to have an unidentified 21 μm emission feature in their IRAS LRS spectra have been obtained using the Kuiper Airborne Observatory.
Harvey, PM, Forveille, T, Loewenstein, RF, Glaccum, W, Kwok, S, Omont, A, Cox, P, Casey, S, Moseley, SH, Chan, KW, Szczerba, R   +10 more
core   +1 more source

Anhydrous minerals in asteroid Bennu: Evidence for well‐preserved primordial components

Meteoritics &Planetary Science, Volume 61, Issue 6, Page 963-986, June 2026.
Abstract Aqueously altered carbonaceous astromaterials are dominated by secondary minerals, but a minor fraction of primary, anhydrous silicates and oxides escape alteration, offering insight into the original composition of asteroid parent bodies. We report the mineralogy, petrology, mineral chemistry, and oxygen isotopes of anhydrous minerals—50 ...
S. S. Russell, I. A. Franchi, T. Salge, X. Zhao, R. H. Jones, A. J. King, N. V. Almeida, P. F. Schofield, H. C. Bates, E. A. Cortes‐Calderon, N. Kawasaki, Y. Yurimoto, Y. Marrocchi, G. Libourel, K. Thomas‐Keprta, L. P. Keller, K. Righter, T. J. McCoy, T. J. Zega, J. J. Barnes, A. N. Nguyen, S. Tachibana, H. C. Connolly Jr, D. S. Lauretta   +23 more
wiley   +1 more source

Photometry and imaging of the peculiar planetary nebula IRAS 21282+5050 [PDF]

, 1993
We report visible, near-infrared, and mid-infrared photometry of the IRAS planetary nebula 21282+5050. Narrow-band photometry at 10 μm confirms the presence of the 11.3 μm PAH feature.
Hrivnak, BJ, Kwok, S, Langill, PP
core   +1 more source

The Secular Evolution of Planetary Nebula IC 418 and Its Implications for Carbon Star Formation

The Astrophysical Journal Letters
The rate of stellar evolution can rarely be measured in real time. The fastest evolution (excluding event-driven evolution), where stars may evolve measurably over decades, is during the post–Asymptotic Giant Branch (AGB) phase. In this Letter we provide
Albert A. Zijlstra, Quentin A. Parker
doaj   +1 more source

On the Variability of the Nuclei of Three Planetary Nebulae [PDF]

Symposium - International Astronomical Union, 1968
The observations of nuclei of three planetary nebulae, NGC 6826, NGC 7662 and IC 4593, have been made as part of a more extensive program with the aim of obtaining their absolute spectrophotometric gradients (ϕ) and photographic magnitudes (from the spectrogram). The spectra were obtained with an 8–12′ Schmidt telescope combined with an objective prism
openaire   +1 more source

Microspherules formed by lightning strikes

Meteoritics &Planetary Science, Volume 61, Issue 5, Page 743-767, May 2026.
Abstract Natural microspherules are formed by high‐temperature processes and are present throughout the geologic record to the present day. We report the discovery of large numbers of microspherules recovered from a rock pavement in the Pilbara region, Western Australia.
M. R. Boyd, M. J. Genge, A. G. Tomkins
wiley   +1 more source