slide1
Download
Skip this Video
Download Presentation
ASPA

Loading in 2 Seconds...

play fullscreen
1 / 19

ASPA - PowerPoint PPT Presentation


  • 124 Views
  • Uploaded on

The international campaign "Photometry and Spectroscopy" of P Cygni. ASPA. Active Spectroscopy in Astronomy. Ernst Pollmann eMail: [email protected] http://www.astrospectroscopy.de. 1. LBV - Characteristics

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' ASPA' - daria-downs


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

The international campaign

"Photometry and Spectroscopy"

of P Cygni

ASPA

Active Spectroscopy

in Astronomy

Ernst Pollmann

eMail: [email protected]

http://www.astrospectroscopy.de

slide3

LBV - Characteristics

    • the most absolute massive and brightest supergiants withmore than 50 solar masses. They go through a very unstable phase with
    • strong variations in brigthness, in color and in their spectra
    • Gravity and pressure don´t keep balanced
    • The stars are unstable
    • They develop strong solar wind (10-3  solar masses per year)
    • Envelope around the star

2

slide4

Photometric Variability

Irregular brigthness variations

Small rapid changes at about 0.01 mag in few hours

Slow changes in the order of 2 mag in years to decades Occasional strong brightness outbursts

AG Carinae

R127

3

slide6

Stellar wind of P Cygni

to the observer

5

slide9

Period Analysis

Main period 1211 d

Phase plot

8

slide11

V (photometr.) [mag]

HαEW [Ǻ]

V (photometr.) [mag]

HαEW [Ǻ]

10

slide12

The EW of a line is a measure of

    • the frequency of a element
    • the density of the gas
    • the temperatur of the layer in which it is developed
  • The Equivalent width indicates how much intensity an absorption line takes away from the continuum or an emission line adds to the continuum

11

slide13

Intensität

Kontinuum

Wellenlänge [Å]

8000

7000

6000

5000

4000

3000

2000

Kontinuum

1000

13

slide14

From the definition of EW

and the relation between stellar magnitudes and continuum flux variations

F2 / F1 = 10-0.4 (m2-m1)

it follows

the line flux is F = C * EW / 10 (0.4 Vphot)

Here is C a constant factor. In practice, we correct EW with a simple division by 10(0.4*Vphot)

Then the derived quantity is not the line flux in physical units, but a quantity proportional to the physical line flux, corrected for continuum variations

14

14

slide15

Evidence of the independency of line flux F & V(photometr.)

F = EW/10^(0.4*V)

15

slide17

Stellar wind of P Cygni

to the observer

17

slide19

EW time behavior of the HeI 6678 absorption

Variable mass loss rate ?

19

ad