scholarly journals On the Progenitor of SNR 0509-67.5

2011 ◽  
Vol 7 (S281) ◽  
pp. 337-340
Author(s):  
Ashley Pagnotta ◽  
Bradley E. Schaefer
Keyword(s):  
Main Sequence ◽  
Large Magellanic Cloud ◽  
Red Giants ◽  
Main Sequence Stars ◽  
The West ◽  
Companion Star ◽  
X Ray ◽  
Type Ia ◽  
Recurrent Nova ◽  
Error Circle

AbstractWe have used three independent methods to determine an accurate and precise geometric center of SNR 0509-67.5, at RA=05:09:31.208, DEC=−67:31:17.48 (J2000). This supernova, which occurred approximately 400 years ago in the Large Magellanic Cloud, was confirmed to be a Type Ia by Rest et al. (2005), Rest et al. (2008) based on spectra of a light echo from the eruption. If this supernova had a single-degenerate progenitor system, we would see the “leftover” companion star within a certain distance of the remnant's center. Accounting for an offset due to enhanced ISM in the west-southwest quadrant of the remnant, we find the eruption position to be at RA=05:09:30.976, DEC=−67:31:17.90; the error circle which should contain any possible ex-companion star has a radius of 1.60″ for 99.73% (3-sigma) containment. This accounts for the proper motion of the stars, the possibility of kicks from the supernova, and asymmetries in the explosion and remnant expansion. We find no possible ex-companion stars within this ellipse, to a limiting magnitude of V=26.9: there are no red giants, which precludes symbiotic progenitors, no subgiants, which when combined with the lack of red giants precludes recurrent nova progenitors, and no main sequence stars with mass greater than 1.16 solar masses (V brighter than 22.7 mag), which precludes persistent supersoft X-ray source progenitors. Indeed, all published SD models are eliminated, so we conclude that this particular Type Ia supernova had a double-degenerate progenitor.

scholarly journals The rate of planet–star coalescences due to tides and stellar evolution

2019 ◽  
Vol 490 (2) ◽  
pp. 2390-2404
Author(s):  
Alexander V Popkov ◽  
Sergei B Popov
Keyword(s):  
Main Sequence ◽  
Tidal Energy ◽  
Red Giants ◽  
Population Synthesis ◽  
Main Sequence Stars ◽  
Tidal Dissipation ◽  
X Ray ◽  
Different Types ◽  
Near Future ◽  
New Facilities

ABSTRACT Orbits of close-in planets can shrink significantly due to dissipation of tidal energy in a host star. This process can result in star–planet coalescence within the Galactic lifetime. In some cases, such events can be accompanied by an optical or/and UV/X-ray transient. Potentially, these outbursts can be observed in near future with new facilities such as LSST from distances about few Mpc. We use a population synthesis model to study this process and derive the rate of star–planet mergers of different types. Mostly, planets are absorbed by red giants. However, these events, happening with the rate about 3 per year, mostly do not produce detectable transients. The rate of mergers with main sequence stars depends on the effectiveness of tidal dissipation; for reasonable values of stellar tidal quality factor, such events happen in a Milky Way-like galaxy approximately once in 70 yr or more rarely. This rate is dominated by planets with low masses. Such events do not produce bright transients having maximum luminosities ≲ 1036.5 erg s−1. Brighter events, related to massive planets, with maximum luminosity ∼1037.5–1038 erg s−1, have the rate nearly five times smaller.

scholarly journals Novae and Accreting White Dwarfs as Progenitors of Type Ia Supernovae

2011 ◽  
Vol 7 (S281) ◽  
pp. 172-180
Author(s):  
Mariko Kato
Keyword(s):  
White Dwarfs ◽  
Main Sequence ◽  
Accretion Rate ◽  
Type Ia Supernovae ◽  
Light Curve Analysis ◽  
X Ray ◽  
Type Ia ◽  
Recurrent Nova ◽  
Red Giant ◽  
Ia Supernovae

AbstractI review various phenomena associated with mass-accreting white dwarfs (WDs) in relation to progenitors of Type Ia supernovae (SNe Ia). The WD mass can be estimated from light curve analysis in multiwavelength bands based on the theory of optically thick winds. In the single degenerate scenario of SNe Ia, two main channels are known, i.e., WD + main sequence (MS) channel and WD + red giant (RG) channel. In each channel, a typical binary undergoes three evolutionary stages before explosion, i.e., the wind phase, supersoft X-ray source (SSS) phase, and recurrent nova phase, in this order because the accretion rate decreases with time as the companion mass decreases. For some accreting WDs we can identify the corresponding stage of evolution. Intermittent supersoft X-ray sources like RX J0513.9−6951 and V Sge correspond to wind phase objects. For the SSS phase, CAL 87-type objects correspond to the WD+MS channel. For the WD + RG channel, soft X-ray observations of early type galaxies give statistical evidence of SSS phase binaries. Recurrent novae of U Sco-type and RS Oph-type correspond to the WD + MS channel and WD + RG channel, respectively. The majority of recurrent novae host a very massive WD (≳ 1.35 M⊙) and often show a plateau phase in their optical light curves corresponding to the long-lasting supersoft X-ray phase. These properties are indications of increasing WD masses.

scholarly journals The empirical Gaia G-band extinction coefficient

2018 ◽  
Vol 614 ◽  
pp. A19 ◽  
Author(s):  
C. Danielski ◽  
C. Babusiaux ◽  
L. Ruiz-Dern ◽  
P. Sartoretti ◽  
F. Arenou
Keyword(s):  
Extinction Coefficient ◽  
Main Sequence ◽  
Spectral Energy Distribution ◽  
Empirical Method ◽  
Spectral Energy ◽  
Red Giants ◽  
Main Sequence Stars ◽  
Empirical Estimation ◽  
Two Samples ◽  
Data Release

Context. The first Gaia data release unlocked the access to photometric information for 1.1 billion sources in the G-band. Yet, given the high level of degeneracy between extinction and spectral energy distribution for large passbands such as the Gaia G-band, a correction for the interstellar reddening is needed in order to exploit Gaia data. Aims. The purpose of this manuscript is to provide the empirical estimation of the Gaia G-band extinction coefficient kG for both the red giants and main sequence stars in order to be able to exploit the first data release DR1. Methods. We selected two samples of single stars: one for the red giants and one for the main sequence. Both samples are the result of a cross-match between Gaia DR1 and 2MASS catalogues; they consist of high-quality photometry in the G-, J- and KS-bands. These samples were complemented by temperature and metallicity information retrieved from APOGEE DR13 and LAMOST DR2 surveys, respectively. We implemented a Markov chain Monte Carlo method where we used (G – KS)0 versus Teff and (J – KS)0 versus (G – KS)0, calibration relations to estimate the extinction coefficient kG and we quantify its corresponding confidence interval via bootstrap resampling. We tested our method on samples of red giants and main sequence stars, finding consistent solutions. Results. We present here the determination of the Gaia extinction coefficient through a completely empirical method. Furthermore we provide the scientific community with a formula for measuring the extinction coefficient as a function of stellar effective temperature, the intrinsic colour (G – KS)0, and absorption.

scholarly journals Activity and rotation of the X-ray emitting Kepler stars

2019 ◽  
Vol 628 ◽  
pp. A41 ◽  
Author(s):  
D. Pizzocaro ◽  
B. Stelzer ◽  
E. Poretti ◽  
S. Raetz ◽  
G. Micela ◽  
...  
Keyword(s):  
White Light ◽  
Main Sequence ◽  
Magnetic Activity ◽  
Light Curves ◽  
Late Type ◽  
Main Sequence Stars ◽  
Photometric Variability ◽  
X Ray ◽  
Rotation Periods ◽  
Flare Frequency

The relation between magnetic activity and rotation in late-type stars provides fundamental information on stellar dynamos and angular momentum evolution. Rotation-activity studies found in the literature suffer from inhomogeneity in the measurement of activity indexes and rotation periods. We overcome this limitation with a study of the X-ray emitting, late-type main-sequence stars observed by XMM-Newton and Kepler. We measured rotation periods from photometric variability in Kepler light curves. As activity indicators, we adopted the X-ray luminosity, the number frequency of white-light flares, the amplitude of the rotational photometric modulation, and the standard deviation in the Kepler light curves. The search for X-ray flares in the light curves provided by the EXTraS (Exploring the X-ray Transient and variable Sky) FP-7 project allows us to identify simultaneous X-ray and white-light flares. A careful selection of the X-ray sources in the Kepler field yields 102 main-sequence stars with spectral types from A to M. We find rotation periods for 74 X-ray emitting main-sequence stars, 20 of which do not have period reported in the previous literature. In the X-ray activity-rotation relation, we see evidence for the traditional distinction of a saturated and a correlated part, the latter presenting a continuous decrease in activity towards slower rotators. For the optical activity indicators the transition is abrupt and located at a period of ~10 d but it can be probed only marginally with this sample, which is biased towards fast rotators due to the X-ray selection. We observe seven bona-fide X-ray flares with evidence for a white-light counterpart in simultaneous Kepler data. We derive an X-ray flare frequency of ~0.15 d−1, consistent with the optical flare frequency obtained from the much longer Kepler time-series.

scholarly journals Excluding supersoft X-ray sources as progenitors for four Type Ia supernovae in the Large Magellanic Cloud

2019 ◽  
Vol 484 (1) ◽  
pp. 1317-1324 ◽  
Author(s):  
J Kuuttila ◽  
M Gilfanov ◽  
I R Seitenzahl ◽  
T E Woods ◽  
F P A Vogt
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Type Ia Supernovae ◽  
X Ray ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals Mass-Losing Peculiar Red Giants: The Comparison Between Theory and Observations

1989 ◽  
Vol 106 ◽  
pp. 339-347
Author(s):  
M. Jura
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Main Sequence ◽  
Mass Loss Rate ◽  
Solar Neighborhood ◽  
Asymptotic Giant Branch ◽  
Red Giants ◽  
Main Sequence Stars ◽  
Dwarf Stars ◽  
White Dwarf Stars

AbstractThe mass loss from evolved red giants is considered. It seems that red giants on the Asymptotic Giant Branch (AGB) are losing between 3 and 6 10-4 MΘ kpc-2 yr-1 in the solar neighborhood. If all the main sequence stars between 1 and 5 MΘ ultimately evolve into white dwarfs with masses of 0.7 MΘ the predicted mass loss rate in the solar neighborhood from these stars is 8 10-4 MΘ kpc-2 yr-1. Although there are still uncertainties, it appears that there is no strong disagreement between theory and observation. However, it could also be that we have not yet identified much of the source of the mass-loss from pre-white dwarf stars.

scholarly journals Supersoft X-ray nebulae in the Large Magellanic Cloud

2020 ◽  
Vol 497 (3) ◽  
pp. 3234-3250 ◽  
Author(s):  
Diego A Farias ◽  
Alejandro Clocchiatti ◽  
Tyrone E Woods ◽  
Armin Rest
Keyword(s):  
Interstellar Medium ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
The Other ◽  
X Rays ◽  
X Ray ◽  
Upper Limits ◽  
Type Ia ◽  
Source Models ◽  
Flux Measurements

ABSTRACT Supersoft X-rays sources (SSSs) have been proposed as potential Type Ia supernova (SN Ia) progenitors. If such objects are indeed persistently X-ray luminous and embedded in sufficiently dense interstellar medium (ISM), they will be surrounded by extended nebular emission. These nebulae should persist even long after an SN Ia explosion, due to the long recombination and cooling times involved. With this in mind, we searched for nebular [O iii] emission around four SSSs and three SNRs in the Large Magellanic Cloud, using the 6.5-m Baade telescope at Las Campanas Observatory and the imacs camera. We confirm that, out of the four SSS candidates, only CAL 83 can be associated with an [O iii] nebula. The [O iii] luminosity for the other objects is constrained to ≲17 per cent of that of CAL 83 at 6.8 pc from the central source. Models computed with the photoionization code cloudy indicate that either the ISM densities in the environments of CAL 87, RX J0550.0-7151, and RX J0513.9-6951 must be significantly lower than surrounding CAL 83 or the average X-ray luminosities of these sources over the last ≲10  000 yr must be significantly lower than presently observed, in order to be consistent with the observed luminosity upper limits. For the three SNRs we consider (all with ages <1000 yr), our [O iii] flux measurements together with the known surrounding ISM densities strongly constrain the ionizing luminosity of their progenitors in the last several thousand years, independent of the progenitor channel.

scholarly journals X-Ray Properties of Pre-Main-Sequence Stars in the Orion Nebula Cluster with Known Rotation Periods

2004 ◽  
Vol 127 (6) ◽  
pp. 3537-3552 ◽  
Author(s):  
Keivan G. Stassun ◽  
David R. Ardila ◽  
Mary Barsony ◽  
Gibor Basri ◽  
Robert D. Mathieu
Keyword(s):  
Main Sequence ◽  
Orion Nebula ◽  
Main Sequence Stars ◽  
X Ray ◽  
Rotation Periods

Pre-main-sequence stars in the stellar association N 11 in the Large Magellanic Cloud: clustering properties

2009 ◽  
Vol 5 (S266) ◽  
pp. 545-548
Author(s):  
Antonella Vallenari ◽  
Rosanna Sordo ◽  
Emanuela Chiosi
Keyword(s):  
Formation Process ◽  
Main Sequence ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Main Sequence Stars ◽  
Stellar Association ◽  
Stellar Objects ◽  
Significant Difference ◽  
Low Metallicity ◽  
Tree Method

AbstractMagellanic Clouds are of extreme importance to study the star-formation process in low-metallicity environments. Here, we discuss the clustering properties of the pre-main-sequence candidates and young embedded stellar objects in N 11, located in the Large Magellanic Cloud. Deep archival HST/ACS photometry is used to derive color–magnitude diagrams of the associations in N 11 and of the foreground field population. These data are complemented by archival infrared Spitzer data which allow detection of young embedded stellar objects. The spatial distribution of the pre-main-sequence candidates and young embedded stellar objects is discussed. The degree of clustering is derived using the minimal-spanning-tree method. No significant difference is found in clustering degree of young blue main-sequence stars and faint pre-main-sequence candidates, suggesting that they might be part of the same formation process.

scholarly journals Non thermal emission from T Tauri stars

2010 ◽  
Vol 6 (S275) ◽  
pp. 404-405
Author(s):  
María V. del Valle ◽  
Gustavo E. Romero
Keyword(s):  
Main Sequence ◽  
Thermal Emission ◽  
High Energy ◽  
Magnetic Activity ◽  
T Tauri Stars ◽  
Main Sequence Stars ◽  
High Energy Radiation ◽  
X Ray ◽  
T Tauri ◽  
Low Mass

AbstractT Tauri stars are low mass, pre-main sequence stars. These objects are surrounded by an accretion disk and present strong magnetic activity. T Tauri stars are copious emitters of X-ray emission which belong to powerful magnetic reconnection events. Strong magnetospheric shocks are likely outcome of massive reconnection. Such shocks can accelerate particles up to relativistic energies through Fermi mechanism. We present a model for the high-energy radiation produced in the environment of T Tauri stars. We aim at determining whether this emission is detectable. If so, the T Tauri stars should be very nearby.

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