Compact Binaries - 3 ASTR2110 Sarazin

Zoology of Binary Stars

X-ray Binary Pulsar Spin-Up Accreted material has high angular momentum Spins up neutron star (true of ~all X-ray binary pulsars)

Millisecond Radio Pulsars Very fast rotation Very weak magnetic field Very Accurate Clocks Many in globular clusters OLD Most are binaries (circles) Not on life track of normal radio pulsars How are they made?

Millisecond Pulsars Accretion spins up NSs in binaries Accretion and age weaken magnetic field After second star dies or accretion stops? Millisecond Pulsars (``Recycled Pulsars ) Older pulsars (many in globular clusters) Most found in binaries Very rapid rotation (P rot ~ 1 msec = 0.001 sec Weak magnetic field, dp/dt ~ 10-20 sec/sec Recently, several objects caught in transition X-ray binary çè millisecond pulsar Very good clocks!!

Binary Pulsars - Tests of General Relativity PSR1913+16 1974, Hulse-Taylor discover Orbital Period 8 hours, very compact Elliptical orbits, determine masses very accurately, ~1.4 M

PSR 1913+16 Orbit contracting due to gravitational waves Rate exactly matches General Relativity All other theories fail

PSR 1913+16 - Noble Prize 1993

Neutron Star Masses X-ray Binary Pulsars and Binary Millisecond Pulsars = NSs in binaries, derive masses

Neutron Star Masses 1.97+- 0.04 Msun NRAO/UVa

Neutron Star Masses X-ray Binary Pulsars and Binary Millisecond Pulsars = NSs in binaries, derive masses Most young NSs have M ~ 1.4 M Formed by collapse of iron core in massive star Maximum mass > 1.97 M Rules out quark matter, other exotic possibilities for NS interiors

Zoology of Binary Stars

First lecture Gamma-Ray Bursts Accidental Discovery 1960 s

Long Bursts: Collapsar Supernova Due to Jets from a Black Hole?

Short Bursts: NS-NS or NS-BH Mergers to Form a Black Hole?

LIGO Detects Gravitational Waves from NS-NS Mergers on August 17!

LIGO Detection GW source = Short GRB in nearby galaxy è Confirms NS-NS merger theory for Short GRB After the burst, kilo-nova = ejection of highly radioactive heavy nuclei made in neutron-rich environment èconfirms theory for production of heaviest elements via NS-NS mergers Where gold comes from

LIGO Detects Gravitational Waves NS-NS Mergers on August 17!

Zoology of Binary Stars

X-ray Binary Black Holes First BH detected Cygnus X-1 Like NSs, but brighter and hotter, no pulses, no nuclear energy Highly irregular emission

X-ray Binary Black Holes Often, first detected as high mass stellar corpse

X-ray Binary Black Holes First BH detected Cygnus X-1 Like NSs, but brighter and hotter, no pulses, no nuclear energy Highly irregular emission Highly Doppler and Gravity (red)shifted X-ray lines

X-ray Line from Black Hole Grav. redshift Dopp redshift Dopp blueshift

Accretion Disks Highly blueshifted and redshifted (Dopper and gravity) from accretion disk gas.

X-ray Line from Black Hole Grav. redshift Dopp redshift Dopp blueshift

X-ray Binary Black Holes First BH detected Cygnus X-1 Like NSs, but brighter and hotter, no pulses, no nuclear energy Highly irregular emission Highly Doppler and Gravity (red)shifted X-ray lines Make both light and kinetic energy in jets

Jets from Black Holes

Jets from Cygnus X-1 BH

Paradox of Black Holes Blackest things in Universe no light escapes from event horizon, but... As material falls in, makes more light than any other objects in Universe Brightest lights in Universe Best garbage disposals in Universe nothing escapes from event horizon, but... As material falls in, part is shot out in jets at v ~ 0.9999 c Most powerful cannons in Universe

Zoology of Binary Stars

First Detection of Gravitational Waves

Gravity waves from 2 merging black holes

Two black holes spiral together and merge 29 M and 36 M è 62 M 3 M into energy, gravitational waves 50 x the luminosity of all the stars in the universe together, for 20 millionths of a sec.

Interstellar Medium ASTR 2110 Sarazin

Interstellar Medium Put you in contact with dead relatives on other planetary systems? NO

Interstellar Medium Most of nearby material is in stars Interstellar space nearly empty (more than lab vacuum) <n> ~ 1 atom/cm 3 But, not empty 1. Gas 2. Dust = small solid particles 3. Relativistic matter 1. Light 2. Cosmic rays = relativistic particles 3. Magnetic fields

Dust 1780 W. Herschel dark nebulae 1847 Struve due to absorption, ~1 mag/kpc 1 kpc = 1000 pc 1930 Trumpler uses open star cluster sizes to measure distance, finds flux < L/(4πd 2 )

f = Dust L no absorption 2 4πd near θ = D d angular diameter log f D = diameter of cluster f = L 4πD 2 θ 2 far log θ

Dust Extinction f = τ = L 4πd 2 e τ absorption κρ dl = κρd d further stars fainter τ d kpc A A m(obs) m(no dust) A extinction + A = 2.5log-, A 1.08τ f (obs). 0 = 2.5log(e τ ) f (no abs) / log f far log θ near

Dust Extinction A V V obs V emit m = M + 5 log d pc 5 + A

Reddening 1940 Stebbins & Whitford photoelectric photometry, reddening, extinction curve Extinction reddens starlight blue near blue star λ red flux distant red star

Extinction curve A λ 1/λ small, solid, dielectric particles = dust grains λ (µ) A λ

Dust Extinction and Reddening

Dust Extinction and Reddening A V V obs V emit m = M + 5 log d pc 5 + A E B-V (B V) obs (B V) emit A V 3 E B-V R E B-V

Example: B0 V (main sequence) star, observed with V = 9.60 and B-V = 0.90. Assume R = 3. What is distance (in pc)? M V = 4.00, M B = 4.30 (Table A.5) E B V = (B V ) obs (B V ) em = (B V ) (M B M V ) = 0.90 ( 4.30 4.00) = 0.9 + 0.3 =1.20 A V = R E B V = 3 1.2 = 3.6 V = M V + 5 log d pc 5 + A V 5logd pc = V M V + 5 A V = 9.6 ( 4.0) 3.6 + 5 =15 d =10 3 pc = 1 kpc