Recent abrupt changes of CW Leonis may indicate that we are witnessing the moment that the central carbon star is evolving off the Asymptotic Giant Branch (AGB) and entering into the pre-planetary nebula (PPN) phase. The recent appearance of a red compact peak at the predicted stellar position is possibly an unveiling event of the star, and the radial beams emerging from the stellar position resemble the feature of the PPN Egg Nebula. The increase of light curve over two decades is also extraordinary, and it is possibly related to the phase transition. Decadal-period variations are further found in the residuals of light curves, in the relative brightness of radial beams, and in the extended halo brightness distribution. Further monitoring of the recent dramatic and decadal-scale changes of this most well-known carbon star CW Leonis at the tip of AGB is still highly essential, and will help us gain a more concrete understanding on the conditions for transition between the late stellar evolutionary phases.

Supernovae (SNe) explode in environments that have been significantly modified by the SN progenitors. For core-collapse SNe, the massive progenitors ionize the ambient interstellar medium (ISM) via UV radiation and sweep the ambient ISM via fast stellar winds during the main sequence phase, replenish the surroundings with stellar material via slow winds during the luminous blue variable (LBV) or red supergiant (RSG) phase, and sweep up the circumstellar medium (CSM) via fast winds during the Wolf-Rayet (WR) phase. If a massive progenitor was in a close binary system, the binary interaction could have caused mass ejection in certain preferred directions, such as the orbital plane, and even bipolar outflow/jet. As a massive star finally explodes, the SN ejecta interacts first with the CSM that was ejected and shaped by the star itself. As the newly formed supernova remnant (SNR) expands further, it encounters interstellar structures that were shaped by the progenitor from earlier times. Therefore, the structure and evolution of a SNR is largely dependent on the initial mass and close binarity of the SN progenitor. The Large Magellanic Cloud (LMC) has an excellent sample of over 50 confirmed SNRs that are well resolved by Hubble Space Telescope, Chandra X-ray Observatory, and Spitzer Space Telescope. These multi-wavelength observations allow us to conduct stellar forensics in SNRs and understand the wide variety of morphologies and physical properties of SNRs observed.

Young Type Ia supernova remnants (SNRs) are characterized by Balmer-dominated optical spectra, well-defined shell morphologies, > 1036 ergs s−1 X-ray luminosities, and a lack of massive stars and dense interstellar gas in their vicinity. Applying these characteristics and using archival deep HST and Chandra observations of M83, we search for young Type Ia SNRs in this spiral galaxy. This is a very difficult task!

As one of the follow-up studies of Herschel Planetary Nebula Survey (HerPlaNS; Ueta et al. 2014), we focus on a bipolar planetary nebula (PN) NGC6781 to characterize the dusty nebula and the central star based on our own Herschel data and the rich archival spectroscopic/photometric image data in the wavelengths from UV to far-IR. With CLOUDY, we constructed a comprehensive photoionization model of NGC6781 ever made including data from UV to radio. We succeeded to reproduce the observed spectral energy distribution (SED) and the atomic gas, H2, CO, and OH molecular line fluxes. We found that about 40% of the total dust mass would be from warm-cold dust components.

The Large Magellanic Cloud (LMC) has been surveyed in optical emission lines, X-rays, radio continuum, HI, and CO lines. These surveys provide views of the interstellar medium (ISM) in the LMC of unprecedented clarity, allowing us to study astrophysical processes and to examine the relationship among the different phases of the ISM. Multi-wavelength images are used to illustrate the physical structures of supernova remnants, superbubbles, and supergiant shells, as well as the global interstellar structure of the LMC.

Before 2012, Commission 34 was identical to Division VI. The organization and executive officers of the Division and the Commission were the same. At the 2012 General Assembly (GA) in Beijing, the IAU reformed the divisional structure and the previous Division VI which Commission 34 was under was combined with Div VII to form Division H: Interstellar Matter and Local Universe. Ewine van Dishoeck was named by the IAU executive committee as the President of the new Division. Since the Commission structure is to be reformed at the GA of 2015, Commission 34 retains its original name “Interstellar Matter” and joined Commissions 33 and 37 (formally under Division VII) as commissions under the new Division H.

We survey HII free-free emission around ∼60 spectroscopically confirmed young stellar objects (YSOs) in the Large Magellanic Cloud using the Australia Telescope Compact Array (ATCA) at 3.3 and 5.5 cm. From each YSOs' infrared spectrum, we: a) quantify how embedded/evolved the YSO is through principle component analysis (PCA) of the silicate absorption (Seale et al. 2009); and b) estimate the mass from SED models (Robitaille et al. 2007). We have four main results: (1) Based on mass estimates from SED models and ATCA detection limits, we find that most massive YSOs are in HII regions regardless of age; (2) Older massive YSOs (as indicated by silicate PCA index) are much more likely to be resolved than younger YSOs, indicating evolving HII regions; (3) Resolved (typically older) sources usually have lower densities. Thus, in our survey we see a transition from ultra-compact HII to HII regions; and (4) We find that accretion about the massive YSO is likely non-spherical, resulting in HII regions in the shape of prolate spheroids.

Extragalactic giant HII regions (EGHRs) are sites of active, concentrated star formation, and thus provide excellent labs to analyze the starburst phenomenon. Although they have been known for a long time, ground-based observations cannot resolve the physical structures and stellar content of EGHRs. The high resolution and sensitivity of Hubble Space Telescope (HST) are ideal for detailed studies of EGHRs. We have searched the Hubble Legacy Archives (HLA) and found 17 nearby galaxies, within ∼15 Mpc, with Hα and continuum images; to determine the best methods for analyzing these data, we perform an in-depth analysis of the EGHRs in M51. M51 is a face-on spiral galaxy ∼8.4 Mpc away, with well-resolved multi-wavelength observations in the HLA. We sample the 25 most luminous HII regions in M51, many of which are bonafide EGHRs with an H-alpha luminosity > 1039 ergs s−1. We use the Hα image to study the distribution and physical structure of the gas in each HII region and determine its Hα luminosity and required ionizing flux. We use the continuum images to determine whether super stellar clusters (SSCs) are found in these HII regions, and use photometric measurements to determine the mass and age spread of the resolved stellar population. These are then compared with the interstellar structures. The results help us provide the groundwork for studying EGHRs in multiple galaxies and elucidate the starburst phenomenon by investigating questions such as: What role does environment play in the formation of EGHRs? How do EGHRs evolve? How does star formation proceed in an EGHR?

The aims of this Working Group are:

• • To ensure that scientific symposia on planetary nebulae take place regularly, ideally every 5 years. These symposia would preferably be sponsored by the IAU;

• • To organize and coordinate the Joint Discussions on the subject at the IAU General Assemblies. These discussions should address topics of interest not only to our Division VI but to other Divisions as well; and

• • To maintain a Web page with general information about the WG, the activities related to planetary nebulae, and the future meetings and symposia.

Division VI, consisting of one Commission (Commission 34) and two Working Groups (Astrochemistry WG and Planetary Nebulae WG), has 972 members whose theoretical, observational, and experimental research interests cover a wide spectrum of activities associated with the study of the interstellar medium (ISM) in the Universe. As such, the Division has close links with Division VIII, IX, and X. The ISM and stars, the two major visible components of a galaxy, are coupled to each other through star formation, stellar feedback, and gravitational potential; thus, the Division is also closely linked to Division VII.

We present XMM-Newton and Chandra observations of the born-again planetary nebula A 30. These X-ray observations reveal a bright unresolved source at the position of the central star whose X-ray luminosity exceeds by far the model expectations for photospheric emission and for shocks within the stellar wind. We suggest that a “born-again hot bubble” may be responsible for this X-ray emission. Diffuse X-ray emission associated with the petal-like features and one of the H-poor knots seen in the optical is also found. The weakened emission of carbon lines in the spectrum of the diffuse emission can be interpreted as the dilution of stellar wind by mass-loading or as the detection of material ejected during a very late thermal pulse.

In our Spitzer 24 μm survey of hot white dwarfs (WDs) we found 9 WDs with IR excesses, 7 of them are still central stars of planetary nebulae (CSPNs). We have thus carried out a Spitzer archival survey of CSPNs, and found additional objects with IR excesses. To date, a total of 13 CSPNs show IR excesses from Spitzer observations. These mid-IR excesses are indicative of the presence of circumstellar dust, which could be produced by collisions or disruption of sub-planetary objects. To further assess the nature of these IR excesses, we have obtained Spitzer IRS, Gemini NIRI and Michelle, and KPNO 4m echelle spectra of these objects. In this poster, we summarize the spectroscopic observations and discuss the nature of these IR excesses.

The Spitzer Space Telescope has three science instruments (IRAC, MIPS, and IRS) that can take images at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm, spectra over 5–38 μm, and spectral energy distribution over 52–100 μm. The Spitzer archive contains targeted imaging observations for more than 100 PNe. Spitzer legacy surveys, particularly the GLIMPSE survey of the Galactic plane, contain additional serendipitous imaging observations of PNe. Spitzer imaging and spectroscopic observations of PNe allow us to investigate atomic/molecular line emission and dust continuum from the nebulae as well as circumstellar dust disks around the central stars. Highlights of Spitzer observations of PNe are reviewed in this paper.

The business meeting of Division VI was held on Monday 10 October 2009. Apologies had been received in advance from D Breitschwerdt, P Caselli, G Ferland, M Juvela, S Lizano, M Rozyczka, V Tóth, M Tsuboi, J Yang and B-C Koo.

Division VI provides a focus for astronomers studying a wide range of problems related to the physical and chemical properties of interstellar matter in the Milky Way and other galaxies.

The interstellar gas of the Magellanic System is subject to the harassment of tidal interactions on galaxy-wide scales and stellar energy feedback on sub-galactic scales. H i surveys of the Magellanic System have produced spectacular images of the tidally displaced interstellar gas in the Magellanic Bridge and Streams. Multi-wavelength observations of the interstellar gas in the Magellanic Clouds have revealed gas components in physical conditions ranging from cold molecular cloud to hot ionized coronal gas. While stellar energy feedback is responsible for heating and dispersing interstellar gas, it can also compress ambient cloud to form stars. I will use Chandra, XMM-Newton, FUSE, HST, Spitzer, ATCA, and other ground-based observations to illustrate the interplay among massive stars, interstellar medium, and star formation.

Massive stars inject energy into the surrounding medium and form shell structures. Bubbles are blown by fast stellar winds from individual massive stars, while superbubbles are blown by fast stellar winds and supernova explosions from groups of massive stars. Bubbles and superbubbles share a similar overall structure: a swept-up dense shell with an interior filled by low-density hot gas. Physical properties of a bubble/superbubble can be affected by magnetic field, thermal conduction, turbulent mixing, inhomogeneous ambient medium, etc. I will review recent progresses on observations and compare them to theoretical expectations for (1) swept-up dense shells, (2) hot interiors, and (3) interface between a dense shell and its interior hot gas.

Division VI gathers astronomers studying the diffuse matter in space between stars, ranging from primordial intergalactic clouds, via dust and neutral and ionized gas in galaxies, to the densest molecular clouds and the processes by which stars are formed.

Evidence for triggered star formation is difficult to establish because energy feedback from massive stars tend to erase the interstellar conditions that led to the star formation. Young stellar objects (YSOs) mark sites of current star formation whose ambient conditions have not been significantly altered. Spitzer observations of the Large Magellanic Cloud (LMC) effectively reveal massive YSOs. The inventory of massive YSOs, in conjunction with surveys of interstellar medium, allows us to examine the conditions for star formation: spontaneous or triggered. We examine the relationship between star formation and gravitational instability on a global scale, and we present evidence of triggered star formation on local scales in the LMC.

Diffuse X-ray emission from hot gas in planetary nebulae (PNe) was hinted by ROSAT and ASCA, but only the improved sensitivity and spatial resolution of XMM-Newton and Chandra have allowed detailed studies of the hot gas in PNe. These studies are helping us to better assess the effects of fast stellar winds and collimated outflows in the shaping and evolution of individual PNe, but a comprehensive picture is lacking, because the X-ray analysis of different PNe is not homogeneous and, therefore, cannot be intercompared. Furthermore, a significant number of X-ray observations of PNe that did not detect X-ray emission have not been reported. We have undertaken a systematic study of all XMM-Newton and Chandra observations of PNe benefiting from a homogeneous analysis using the most up-to-date versions of SAS and CIAO, respectively, and the recently released calibration files with greater accuracy for energies below 1.0 keV. We present reprocessed event files, derived data products (X-ray images and spectra), supporting observations at other wavelengths, and analysis results in a database, the XPN Database, that can be accessed at http://www.iaa.csic.es/xpn