Where are the stripped donor stars? - lorentzcenter.nl fileWhere are the stripped donor stars?...
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Where are the stripped donor stars? Insights from the φ Persei system Image credit: Hubble ESA Information Center Abel Schootemeijer University of Amsterdam Supervisor : Selma de Mink Collaborators : Ylva Götberg , Manos Zapartas , Doug Gies , Hugues Sana
Transcript of Where are the stripped donor stars? - lorentzcenter.nl fileWhere are the stripped donor stars?...
Where are the
stripped donor stars?Insights from the φ Persei system
Image credit: Hubble ESA Information Center
Abel SchootemeijerUniversity of Amsterdam
Supervisor: Selma de MinkCollaborators: Ylva Götberg, Manos Zapartas,
Doug Gies, Hugues Sana
0 Myr
No/before
interaction:
30 Dor O star population – constant star formation
Pre-interaction binaries
Single stars*See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
binary_cFast binary evolution code*
• Uses pre-computed grid
• ~106 systems day-1
0 Myr 10 Myr
No/before after
interaction: interaction:
30 Dor O star population – constant star formation
Pre-interaction binaries
Single stars
Other post-interaction sys.
Mergers
He star systems *See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
binary_cFast binary evolution code*
• Uses pre-computed grid
• ~106 systems day-1
0 Myr 10 Myr 20 Myr
No/before after
interaction: interaction:
30 Dor O star population – constant star formation
Pre-interaction binaries
Single stars
Other post-interaction sys.
Mergers
He star systems *See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
binary_cFast binary evolution code*
• Uses pre-computed grid
• ~106 systems day-1
0 Myr 10 Myr 20 Myr 40+ Myr
No/before after
interaction: interaction:
30 Dor O star population – constant star formation
Pre-interaction binaries
Single stars
Other post-interaction sys.
Mergers
He star systems *See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
binary_cFast binary evolution code*
• Uses pre-computed grid
• ~106 systems day-1
40+ Myr
No/before after
interaction: interaction:
O star population – constant star formation
Pre-interaction binaries
Single stars
Other post-interaction sys.
Mergers
He star systems *See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
binary_cFast binary evolution code*
• Uses pre-computed grid
• ~106 systems day-1
1/3 post interaction systems
contains a stripped He star: this is in agreement with Pols+1991
Why are stripped donor
stars hard to find? Only three have been observed
Why are stripped donor
stars hard to find? Only three have been observed
Extreme mass ratio and
widening of semi-major axisLow vorb of the
brightest star
Why are stripped donor
stars hard to find? Only three have been observed
Extreme mass ratio and
widening of semi-major axisLow vorb of the
brightest star
Bright companions Stripped stars are hard to
detect in a spectrum
Why are stripped donor
stars hard to find? Only three have been observed
Extreme mass ratio and
widening of semi-major axisLow vorb of the
brightest star
Bright companions Stripped stars are hard to
detect in a spectrum
‘Stripped stars are HOT’ *
Most light is emitted in UV
Fewer lines in spectrum
*Credit: Ylva Götberg
Be star
9.6 ± 0.3 Mʘ
104.16±0.10 Lʘvrot ≈ 0.9 vcrit
sdO companion
1.2 ± 0.2 Mʘ
103.80±0.13 Lʘ53 ± 3 kK
In φ Persei a stripped companion is found:
Porb = 126 d *Campbell, 1902
**Gies+1998, Mourard+2015
• Radial velocity variations observed*
• Full orbital solution now determined**
Be star
9.6 ± 0.3 Mʘ
104.16±0.10 Lʘvrot ≈ 0.9 vcrit
sdO companion
1.2 ± 0.2 Mʘ
103.80±0.13 Lʘ53 ± 3 kK
In φ Persei a stripped companion is found:
Porb = 126 d
Why is the stripped
star so bright?
Computational method: BINARY_C
• Bayesian analysis to determine initial parameters:
Star 1: 7.2 ± 0.5 Mʘ
Star 2: 3.8 ± 0.5 Mʘ
Porb: 17 ± 5 days
Computational method: BINARY_C
• Bayesian analysis to determine initial parameters:
Star 1: 7.2 ± 0.5 Mʘ
Star 2: 3.8 ± 0.5 Mʘ
Porb: 17 ± 5 days
>99.9% probability to
fit to helium shellburning phase
Stripped helium stars of various Mʘ
• No core helium burning helium stars seem to fit
MHe*,obs = 1.2 ± 0.2 Mʘ
Stripped helium stars of various Mʘ
• No core helium burning helium stars seem to fit
MHe*,obs = 1.2 ± 0.2 Mʘ
The φ Persei family
• For similar systems, only 2% is as bright as φ Persei’s hot companion ~50 less luminous He star systems expected (φ Per)-1
The φ Persei family
• For similar systems, only 2% is as bright as φ Persei’s hot companion ~50 less luminous He star systems expected (φ Per)-1
Proposed topic of discussion:
How to systematically search for
stripped donor stars?
Emergency slide I
Emergency slide II
Is a case A mass transfer scenario possible?
From J-conservation it follows that (if mass is conserved):𝑃
𝑃0
= (𝑀1
,0𝑀2
,0
𝑀1𝑀2
)3
• Even with M1,0 = M2,0 = 5.4 Mʘ P0 = 8 d is needed to reach
P = 126 d, M1 = 1.2 Mʘ and M2 = 9.6 Mʘ
Image credit: Hubble ESA Information Center
Emergency slide III – detailed model
Observations
of He star
Onset of He
shell burning
time
Computational method: BINARY_C
Grid:• Z = 0.02
• Salpeter IMF: df ~ M1-2.35 dM1
• Flat mass ratio distribution
• fP ~ (log10(P/d))0 (Öpik’s law)
*See Hurley+00, 02
Izzard+04, 06, 09de Mink+13
Physics assumptions:• Accretion limited by 10*Macc / tthermal
• Angular momentum loss bipolar outflow
from accretor star
binary_cFast binary evolution code*
• ~106 systems day-1
• Does not solve stellar structure
