分类： 天文学 >> 天文学 提交时间： 2023-02-19
Orsola De Marco
Muhammad Akashi
Stavros Akras
Javier Alcolea
Isabel Aleman
Philippe Amram
Bruce Balick
Elvire De Beck
Eric G. Blackman
Henri M. J. Boffin
Panos Boumis
Jesse Bublitz
Beatrice Bucciarelli
Valentin Bujarrabal
Jan Cami
Nicholas Chornay
You-Hua Chu
Romano L. M. Corradi
Adam Frank
Guillermo Garcia-Segura
摘要： Planetary nebulae (PNe), the ejected envelopes of red giant stars, provide us with a history of the last, mass-losing phases of 90 percent of stars initially more massive than the Sun. Here, we analyse James Webb Space Telescope (JWST) Early Release Observation (ERO) images of the PN NGC3132. A structured, extended H2 halo surrounding an ionised central bubble is imprinted with spiral structures, likely shaped by a low-mass companion orbiting the central star at 40-60 AU. The images also reveal a mid-IR excess at the central star interpreted as a dusty disk, indicative of an interaction with another, closer companion. Including the previously known, A-type visual companion, the progenitor of the NGC3132 PN must have been at least a stellar quartet. The JWST images allow us to generate a model of the illumination, ionisation and hydrodynamics of the molecular halo, demonstrating the power of JWST to investigate complex stellar outflows. Further, new measurements of the A-type visual companion allow us to derive the value for the mass of the progenitor of a central star to date with excellent precision: 2.86+/-0.06 Mo. These results serve as path finders for future JWST observations of PNe providing unique insight into fundamental astrophysical processes including colliding winds, and binary star interactions, with implications for supernovae and gravitational wave systems.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： This paper systematically studies the relation between metallicity and mass
loss of massive stars. We perform one-dimensional stellar evolution simulations
and build a grid of $\sim$2000 models with initial masses ranging between 11
and 60 $M_{\odot}$ and absolute metallicities $Z$ between 0.00001 and 0.02.
Steady-state winds, comprising hot main-sequence winds and cool supergiant
winds, are the main drivers of the mass loss of massive stars in our models. We
calculate the total mass loss over the stellar lifetime for each model. Our
results reveal the existence of a critical metallicity $Z_{\rm{c}}$ at $Z \sim
10^{-3}$, where the mass loss exhibits a dramatic jump. If $Z>Z_{\rm{c}}$,
massive stars tend to evolve into cool supergiants, and a robust cool wind is
operational. In contrast, if $Z
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： 1E 0102.2--7219 (hereafter E0102) is a young supernova remnant (SNR) in the Small Magellanic Cloud (SMC). It contains oxygen-rich SN ejecta, a possible neutron star (NS), and a small amount of fast-moving H-rich ejecta material. These properties are also seen in Cas A, it has thus been suggested that E0102 is also a Type IIb SNR, whose SN progenitor's hydrogen envelope was stripped off possibly via interactions with a companion star. To search for a surviving companion of E0102's SN progenitor, we have used archival Hubble Space Telescope (HST) continuum images to make photometric measurements of stars projected in the SNR to construct color-magnitude diagrams and compare the stars with those expected from surviving companions of Type IIb SNe. We have also used the Multi-Unit Spectroscopic Explorer observations taken with the Very Large Telescope to perform spectroscopic analyses of stars and search for peculiar radial velocities as diagnostics of surviving companions. We further use the HST and Gaia data to inspect proper motions of stars for complementary kinetic studies. No plausible companion candidates are found if the SN explosion site was near the NS, while the B3 V star 34a may be a plausible companion candidate if the SN explosion site is near the SN ejecta's expansion center. If the NS is real and associated with E0102, it needs a ~1000 km/s runaway velocity, which has been observed in other SNRs and can be acquired from an asymmetric SN explosion or a kick by the SN explosion of a massive companion.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Chuan-Jui Li
Wolfgang E. Kerzendorf
You-Hua Chu
Ting-Wan Chen
Tuan Do
Robert A. Gruendl
Abigail Holmes
Ryoko Ishioka
Bruno Leibundgut
Kuo-Chuan Pan
Paul M. Ricker
Daniel Weisz
摘要： We have used two methods to search for surviving companions of Type Ia supernova progenitors in three Balmer-dominated supernova remnants (SNRs) in the Large Magellanic Cloud: 0519-69.0, 0505-67.9 (DEM L71), and 0548-70.4. In the first method, we use the Hubble Space Telescope photometric measurements of stars to construct color-magnitude diagrams (CMDs), and compare positions of stars in the CMDs with those expected from theoretical post-impact evolution of surviving main sequence or helium star companions. No obvious candidates of surviving companion are identified in this photometric search. Future models for surviving red giant companions or with different explosion mechanisms are needed for thorough comparisons with these observations in order to make more definitive conclusions. In the second method, we use Multi-Unit Spectroscopic Explorer (MUSE) observations of 0519-69.0 and DEM L71 to carry out spectroscopic analyses of stars in order to use large peculiar radial velocities as diagnostics of surviving companions. We find a star in 0519-69.0 and a star in DEM L71 moving at radial velocities of 182 $\pm$ 0 km s$^{-1}$ and 213 $\pm$ 0 km s$^{-1}$, more than 2.5$\sigma$ from the mean radial velocity of the underlying stellar population, 264 km s$^{-1}$ and 270 km s$^{-1}$, respectively. These stars need higher-quality spectra to investigate their abundances and rotation velocities to determine whether they are indeed surviving companions of the SN progenitors.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Balmer-dominated shells in supernova remnants (SNRs) are produced by collisionless shocks advancing into a partially neutral medium, and are most frequently associated with Type Ia supernovae. We have analyzed Hubble Space Telescope (HST) images and VLT/MUSE or AAT/WiFeS observations of five Type Ia SNRs containing Balmer-dominated shells in the LMC: 0509-67.5, 0519-69.0, N103B, DEM L71, and 0548-70.4. Contrary to expectations, we find bright forbidden line emission from small dense knots embedded in four of these SNRs. The electron densities in some knots are higher than 10$^4$ cm$^{-3}$. The size and density of these knots are not characteristic for interstellar medium (ISM) -- they most likely originate from a circumstellar medium (CSM) ejected by the SN progenitor. Physical property variations of dense knots in the SNRs appear to reflect an evolutionary effect. The recombination timescales for high densities are short, and HST images of N103B taken 3.5 yr apart already show brightness changes in some knots. VLT/MUSE observations detect [Fe XIV] line emission from reverse shocks into SN ejecta as well as forward shocks into the dense knots. Faint [O III] line emission is also detected from the Balmer shell in 0519-69.0, N103B, and DEM L71. We exclude the postshock origin because the [O III] line is narrow. For the preshock origin, we considered three possibilities: photoionization precursor, cosmic ray precursor, and neutral precursor. We conclude that the [O III] emission arises from oxygen that has been photoionized by [He II] $\lambda$304 photons and is then collisionally excited in a shock precursor heated mainly by cosmic rays.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The supernova remnant (SNR) B0532$-$67.5 in the Large Magellanic Cloud (LMC) was first diagnosed by its nonthermal radio emission and its SNR nature was confirmed by diffuse X-ray emission; however, no optical SNR shell is detected. The OB association LH75, or NGC 2011, is projected within the boundary of this SNR. We have analyzed the massive star population in and around SNR B0532$-$67.5: using optical photometric data to construct color-magnitude diagrams (CMDs), using stellar evolutionary tracks to estimate stellar masses, and using isochrones to assess the stellar ages. From these analyses, we find a 20-25 Myr population in LH75 and a younger population less than 10 Myr old to the southwest of LH75. The center of SNR B0532$-$67.5 is located closer to the core of LH75 than the massive stars to its southwest. We conclude that the SN progenitor was probably a member of LH75 with an initial mass $\sim$15 $M_\odot$. The SN exploded in an H I cavity excavated by the energy feedback of LH75. The low density of the ambient medium prohibits the formation of a visible nebular shell. Despite the low density in the ambient medium, physical properties of the hot gas within the SNR interior do not differ from SNRs with a visible shell by more than a factor of 2-3. The large-scale H I map shows that SNR B0532$-$67.5 is projected in a cavity that appears to be connected with the much larger cavity of the supergiant shell LMC-4.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： This paper systematically studies the relation between metallicity and mass
loss of massive stars. We perform one-dimensional stellar evolution simulations
and build a grid of $\sim$2000 models with initial masses ranging between 11
and 60 $M_{\odot}$ and absolute metallicities $Z$ between 0.00001 and 0.02.
Steady-state winds, comprising hot main-sequence winds and cool supergiant
winds, are the main drivers of the mass loss of massive stars in our models. We
calculate the total mass loss over the stellar lifetime for each model. Our
results reveal the existence of a critical metallicity $Z_{\rm{c}}$ at $Z \sim
10^{-3}$, where the mass loss exhibits a dramatic jump. If $Z>Z_{\rm{c}}$,
massive stars tend to evolve into cool supergiants, and a robust cool wind is
operational. In contrast, if $Z
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