Discovery of tidal debris stars from G1/Mayall-II in M31

2021 ◽  
Author(s):  
Michael D Gregg ◽  
Michael J West ◽  
Brian C Lemaux ◽  
Andreas H W Küpper
Keyword(s):  
Globular Cluster ◽  
Loss Rate ◽  
Dwarf Galaxy ◽  
Mass Loss Rate ◽  
Dissolution Time ◽  
Stellar Systems ◽  
Advanced Stage ◽  
Stellar Envelope ◽  
Tidal Tail ◽  
Systemic Velocity

Abstract The object Mayall II or G1 is the brightest globular cluster belonging to M31. Because of its extreme properties for a globular cluster, it has been speculated that G1 is the remnant nucleus of a dwarf galaxy that has been stripped by the tidal field of M31. Using the Keck DEIMOS spectrograph, we have conducted a survey for tidally stripped stars from G1, obtaining a sample of 351 stellar velocities over ∼ 320 sq. arcminutes of sky centered on G1. Thirteen are within $25~{\, \rm km\, s^{-1}\, }$ of the systemic velocity of G1, and exhibit spatial and velocity correlations consistent with being dynamically associated with G1, and all thirteen are well outside the tidal radius of the cluster. These thirteen stars could be either (i) the remnants of an almost completely evaporated stellar envelope, or (ii) G1 member stars lost through tidal interaction with M31. Estimates of the implied mass loss rate based on our data suggest a short dissolution time-scale for G1, thus favouring the stellar envelope hypothesis for the origin of the tidal tail stars, or, at the very least, an advanced stage of cluster dissolution. In either case, G1, and by extension compact stellar systems in general, have likely played a significant role in building the halo of M31.

scholarly journals Enhanced mass-loss rate evolution of stars with ≳18 M⊙ and missing optically observed type II core-collapse supernovae

2020 ◽  
Vol 494 (4) ◽  
pp. 5230-5238
Author(s):  
Roni Anna Gofman ◽  
Naomi Gluck ◽  
Noam Soker
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Main Sequence ◽  
Mass Loss Rate ◽  
Core Collapse ◽  
Type Ii ◽  
Instability Strip ◽  
Stellar Envelope ◽  
Explosion Mechanism ◽  
Hydrogen Mass

ABSTRACT We evolve stellar models with zero-age main-sequence (ZAMS) mass of MZAMS ≳ 18 M⊙ under the assumption that they experience an enhanced mass-loss rate when crossing the instability strip at high luminosities and conclude that most of them end as type Ibc supernovae (SNe Ibc) or dust-obscured SNe II. We explore what level of enhanced mass-loss rate during the instability strip would be necessary to explain the ‘red supergiant problem’. This problem refers to the dearth of observed core-collapse supernovae progenitors with MZAMS ≳ 18 M⊙. Namely, we examine what enhanced mass-loss rate could make it possible for all these stars actually to explode as core-collapse supernovae (CCSNe). We find that the mass-loss rate should increase by a factor of at least about 10. We reach this conclusion by analysing the hydrogen mass in the stellar envelope and the optical depth of the dusty wind at the explosion, and crudely estimate that under our assumptions only about a fifth of these stars explode as unobscured SNe II and SNe IIb. About 10–15 per cent end as obscured SNe II that are infrared-bright but visibly very faint, and the rest, about 65–70 per cent, end as SNe Ibc. However, the statistical uncertainties are still too significant to decide whether many stars with MZAMS ≳ 18 M⊙ do not explode as expected in the neutrino driven explosion mechanism, or whether all of them explode as CCSNe, as expected by the jittering jets explosion mechanism.

scholarly journals Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf

2022 ◽  
Vol 924 (1) ◽  
pp. 15
Author(s):  
W. V. Jacobson-Galán ◽  
L. Dessart ◽  
D. O. Jones ◽  
R. Margutti ◽  
D. L. Coppejans ◽  
...  
Keyword(s):  
Light Curve ◽  
Mass Loss ◽  
Loss Rate ◽  
Main Sequence ◽  
Mass Loss Rate ◽  
Type Ii ◽  
Stellar Envelope ◽  
Circumstellar Material ◽  
Associated Mass ◽  
Flash Spectroscopy

Abstract We present panchromatic observations and modeling of supernova (SN) 2020tlf, the first normal Type II-P/L SN with confirmed precursor emission, as detected by the Young Supernova Experiment transient survey. Pre-SN activity was detected in riz-bands at −130 days and persisted at relatively constant flux until first light. Soon after discovery, “flash” spectroscopy of SN 2020tlf revealed narrow, symmetric emission lines that resulted from the photoionization of circumstellar material (CSM) shed in progenitor mass-loss episodes before explosion. Surprisingly, this novel display of pre-SN emission and associated mass loss occurred in a red supergiant (RSG) progenitor with zero-age main-sequence mass of only 10–12 M ⊙, as inferred from nebular spectra. Modeling of the light curve and multi-epoch spectra with the non-LTE radiative-transfer code CMFGEN and radiation-hydrodynamical code HERACLES suggests a dense CSM limited to r ≈ 1015 cm, and mass-loss rate of 10−2 M ⊙ yr−1. The luminous light-curve plateau and persistent blue excess indicates an extended progenitor, compatible with an RSG model with R ⋆ = 1100 R ⊙. Limits on the shock-powered X-ray and radio luminosity are consistent with model conclusions and suggest a CSM density of ρ < 2 × 10−16 g cm−3 for distances from the progenitor star of r ≈ 5 × 1015 cm, as well as a mass-loss rate of M ̇ < 1.3 × 10 − 5 M ☉ yr − 1 at larger distances. A promising power source for the observed precursor emission is the ejection of stellar material following energy disposition into the stellar envelope as a result of gravity waves emitted during either neon/oxygen burning or a nuclear flash from silicon combustion.

scholarly journals Evolutionary effects of mass loss in low-mass stars

1981 ◽  
Vol 59 ◽  
pp. 319-338
Author(s):  
Alvio Renzini
Keyword(s):  
Mass Loss ◽  
Globular Cluster ◽  
Planetary Nebula ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Central Star ◽  
Red Giants ◽  
Low Mass Stars ◽  
Low Mass ◽  
Actual Mass

AbstractThe effects of mass loss on the evolution of low-mass stars (actual mass smaller than 1.4 Mʘ) are reviewed. The case of globular cluster stars is discussed in some detail, and it is shown that evolutionary theory sets quite precise limits to the mass-loss rate in population II red giants. The effects of mass loss on the final evolutionary stages of stars producing white dwarfs is also discussed. In particular, the interaction of the wind from the hot central star with the surrounding planetary nebula is considered. Finally, the problem of the origin of hydrogen-deficient stars is briefly discussed.

scholarly journals SN 2009ip: CONSTRAINTS ON THE PROGENITOR MASS-LOSS RATE

2013 ◽  
Vol 768 (1) ◽  
pp. 47 ◽  
Author(s):  
E. O. Ofek ◽  
L. Lin ◽  
C. Kouveliotou ◽  
G. Younes ◽  
E. Göğüş ◽  
...  
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate

scholarly journals On the origin of the helium-rich population in the peculiar globular cluster Omega Centauri

2009 ◽  
Vol 5 (S268) ◽  
pp. 187-188
Author(s):  
Donatella Romano ◽  
M. Tosi ◽  
M. Cignoni ◽  
F. Matteucci ◽  
E. Pancino ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Globular Cluster ◽  
Main Sequence ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Potential Well ◽  
Galactic Winds ◽  
Supernova Explosions

AbstractIn this contribution we discuss the origin of the extreme helium-rich stars which inhabit the blue main sequence (bMS) of the Galactic globular cluster Omega Centauri. In a scenario where the cluster is the surviving remnant of a dwarf galaxy ingested by the Milky Way many Gyr ago, the peculiar chemical composition of the bMS stars can be naturally explained by considering the effects of strong differential galactic winds, which develop owing to multiple supernova explosions in a shallow potential well.

scholarly journals AGB Winds with Gas-Dust Drift in Stellar Evolution Codes

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 113
Author(s):  
Lars Mattsson ◽  
Christer Sandin
Keyword(s):  
Stellar Evolution ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Carbon Star ◽  
Intermediate Mass ◽  
Future Directions ◽  
Physical Description ◽  
Intermediate Mass Stars ◽  
Dust Component ◽  
Improved Model

A significant fraction of new metals produced in stars enter the interstellar medium in the form of dust grains. Including dust and wind formation in stellar evolution models of late-stage low- and intermediate-mass stars provides a way to quantify their contribution to the cosmic dust component. In doing so, a correct physical description of dust formation is of course required, but also a reliable prescription for the mass-loss rate. Here, we present an improved model of dust-driven winds to be used in stellar evolution codes and insights from recent detailed numerical simulations of carbon-star winds including drift (decoupling of dust and gas). We also discuss future directions for further improvement.

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