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10 Results Found

  • Article
  • Open Access
4 Citations
2,615 Views
13 Pages

AGB Stars and Their Circumstellar Envelopes. I. the VULCAN Code

  • Sergio Cristallo,
  • Luciano Piersanti,
  • David Gobrecht,
  • Lucio Crivellari and
  • Ambra Nanni

The interplay between AGB interiors and their outermost layers, where molecules and dust form, is a problem of high complexity. As a consequence, physical processes like mass loss, which depend on the chemistry of the circumstellar envelope, are ofte...

  • Article
  • Open Access
2,080 Views
12 Pages

10 September 2021

The study of AGB stars necessarily covers a wide range of topics, from the primary astronomical observations to their interpretation in terms of fundamental physics. All that requires proper ad hoc methodologies, among which numerical modeling of the...

  • Article
  • Open Access
2,827 Views
5 Pages

Infrared Observations of the Asymmetric Mass Loss of an AGB Star

  • Foteini Lykou,
  • Albert A. Zijlstra,
  • Jacques Kluska,
  • Eric Lagadec,
  • Peter G. Tuthill,
  • Adam Avison,
  • Barnaby R. M. Norris and
  • Quentin A. Parker

12 October 2018

We report on the observations of the circumstellar envelope of the AGB star II Lup in the near- and mid-infrared with the use of direct imaging and interferometric techniques. Our findings indicate that the circumstellar envelope is not spherically s...

  • Feature Paper
  • Article
  • Open Access
3,175 Views
9 Pages

DEATHSTAR—CO Envelope Size and Asymmetry of Nearby AGB Stars

  • Miora Andriantsaralaza,
  • Wouter Vlemmings,
  • Sofia Ramstedt and
  • Elvire De Beck

12 February 2022

Low- and intermediate-mass stars evolve into asymptotic giant branch (AGB) stars near the end of their lives, losing mass through slow and massive winds. The ejected material creates a chemically-rich expanding envelope around the star, namely the ci...

  • Review
  • Open Access
7 Citations
2,290 Views
18 Pages

Presolar grains are microscopic dust grains that formed in the stellar winds or explosions of ancient stars that died before the formation of the solar system. The majority (~90% in number) of presolar silicon carbide (SiC) grains, including types ma...

  • Article
  • Open Access
2 Citations
3,964 Views
9 Pages

ALMA’s Acute View of pPNe: Through the Magnifying Glass... and What We Found There

  • Carmen Sánchez Contreras,
  • Javier Alcolea,
  • Valentín Bujarrabal and
  • Arancha Castro-Carrizo

4 September 2018

We present recent Atacama Large Millimeter/submillimeter Array (ALMA)-based studies of circumstellar envelopes (CSEs) around Asymptotic Giant Branch (AGB) stars and pre-Planetary Nebulae (pPNe). In only a few years of operation, ALMA is revolutionisi...

  • Article
  • Open Access
7 Citations
2,515 Views
17 Pages

Dust Production around Carbon-Rich Stars: The Role of Metallicity

  • Ambra Nanni,
  • Sergio Cristallo,
  • Jacco Th. van Loon and
  • Martin A. T. Groenewegen

Background: Most of the stars in the Universe will end their evolution by losing their envelope during the thermally pulsing asymptotic giant branch (TP-AGB) phase, enriching the interstellar medium of galaxies with heavy elements, partially condense...

  • Article
  • Open Access
1 Citations
890 Views
11 Pages

31 March 2025

We present the results of photometric and spectroscopic observations of a poorly studied B-type supergiant with infrared excess, the hot post-AGB star IRAS 21546+4721. Based on our photometric observations in the UBVRCIC bands, we detected rapid, nig...

  • Article
  • Open Access
3 Citations
6,346 Views
17 Pages

12 August 2020

Most stars in the Universe that leave the main sequence in a Hubble time will end their lives evolving through the Planetary Nebula (PN) evolutionary phase. The heavy mass loss which occurs during the preceding Asymptotic Giant Branch (AGB) phase is...

  • Article
  • Open Access
5 Citations
2,463 Views
11 Pages

The Ionization Energies of Dust-Forming Metal Oxide Clusters

  • David Gobrecht,
  • Jan Philip Sindel,
  • Helena Lecoq-Molinos and
  • Leen Decin

Stellar dust grains are predominantly composed of mineralic, anorganic material forming in the circumstellar envelopes of oxygen-rich AGB stars. However, the initial stage of the dust synthesis, or its nucleation, is not well understood. In particula...