* ** = SUMER spectra Continuum measurements 1 st - order = 1350 Å, 2 nd -order = 675 Å 1 st- and 2 nd -order continuum near.

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SUMER spectra

Continuum measurements

• 1st- order = 1350 Å, 2nd-order = 675 Å

• 1st- and 2nd-order continuum near Fe XII

• 2nd-order continuum near C II

• 2nd- order more apt to be absorbed by H I

• Ratio of 1st-to-2nd-order cont. shows location of absorption

Time-space “stackplots”

Time-space “stackplots”

Dark in emission lines not “hot + dense”

Continuum ratio maps

(3.5 x 1st-order 2nd-order)

(bremsstrahlung ratio=1)

Binaries•Visual binary (VB) – see both stars

•Astrometric binary (AB) – see one, but it “wiggles”

•Spectroscopic binary (SB) – see one, but line-of-sight velocity oscillates

•Eclipsing binary (EB) – light curve

SB:

Splitting or shifting of spectral lines

•“single line”, one star much brighter than the other, compare shift to local calibration lamp

•“double line”, see spectrum from both stars

Radial velocity v = c / 0

“double line” ratio of v1/v2 yields M2/M1

If (R+r)/a cos(inclination), then EB

Fake simple eclipse•Deeper “primary” eclipse is when the hotter star is hidden

•A flat bottom to the eclipse indicates that the star is completely obscured

•Time in eclipse, as fraction of the total period, yields info about relative sizes, separation, even tidal bulge

Example: oblate spheroid with a tidal bulge

Example: brightening around secondary

minimum?

Answer: brighter star reflects off the fainter star

If you can observe Then you can compute If also know Then

(1a) Apparent orbit of VB, relative only

P, a”, e, incl. ” a, M1 + M2

(1b) Apparent orbit of VB, center-of-mass

P, a1”, a2”, e, incl. ” a1, a2, M1, M2

(2) Light curve of EB P, incl., R1/a, R2/a, relative temp.

(3a) Radial velocity of SB, single line

P, (a1sin(incl.)), e

(3b) Radial velocity of SB, double line

P, (a1sin(incl.)), (a2sin(incl.)), e

P = period

a” = semimajor axis of relative orbit (arcsec)

a = semimajor axis of absolute orbit (a.u., or pc)

” = parallax (arcsec)