Krüger 60

[starf]

This is an interesting red dwarf binary in cepheus. The separation is only arc 2 secs and as seen in the image its failed miserably to split it. The B component is interesting, or at least would be if it was split, as it is a flare star - thought to be the result of huge magnetic fields caused by the rotation of the newly formed dwarf M star.

Does anybody have any idea of the amount of magnification necessary to split it?

the 285 chip gives something like a 9mm fov so its around 111 mag on this 1000mm reflector. just looking at Krüger 60 the diameter in the image is something like 10 arc secs, so even a 2x increase is unlikely to have much effect.

regards

mike.

[barkis]

That is a splendid Image Mike, and a very informative one. The attempt to split a double at 2 arc seconds is obviously not easy. To increase the power necessary to do so, would require perfect conditions as regards seeing and steadiness. Also, without saying, a reduced FOV.

I saw a great image of the epsilon Lyra double double on the forum a while ago, but I don't remember who submitted it. They were clearly separated in that image, although I am not sure what the separation distances were.

Maybe Ian (Lunator) could give you some assistance, he is a double star specialist.

He may read your post and come in, or you could perhaps PM him.

Anyway, as I said, a wonderful piece of work there.

Ron.

[Andrew*]

Hi Starf.

Ron, by the way, it was Paxo: http://stargazerslounge.com/index.php/topic,29466.msg299803.html#msg299803

The separations of the double double are 2.6 and 2.3, so not a lot wider than this pair.

I would reckon you could get this split with your set up including the barlow. I've split all the ?-Lyrae components at about 200x in a 4" refractor.

HTH

Andrew

[lunator]

Hi Mike

Spliting doubles this faint/tight can be tricky.

Whilst the double/double are of similar separation the brightness of the components make them easier to split. I can split them easily at x150 in the ST120.

As a useful analogue I had to use x300 to split a 12th magnitude pair ROE98 which are separated by 4.7". This was in my 10" scope.

You may be able to get a split with a 3x barlow.

Cheers

Ian

[starf]

Hi all, thanks very much for the help.

it seems to be down to the apparent radii of the two systems. the double double stars are obviously hotter than kruger 60, since luminosity depends radius and well tested radiation laws, but they are also more distant. whilst kruger 60 is fainter its apparent radii is much larger (see paxo's image) due to its proximity to earth. This appears to encrouch on DO cep and with only a caculated 9.2AU separation (saturn to the sun), will take a bit more to split them.

ever since seeing that image of the flare taken by the yerkes observatory, ive been itching to see if its possible to put an animated gif together not only of the flare but since it's a close binary both to the earth and to each other, the change in position angle is also quite pronounced.

here's the images from yerkes.

kind regards

mike

[starf]

lol ron your not kidding when you say it needs good conditions!

here's the results at 2000mm & 4000mm the seeing was bouncing around all over the place, but look... absolutely nothing

regards

mike

[barkis]

Hi Mike, I confess to not being too knowlegable on Binary stars, so I have been reading up on Kruger 60 in Burnhams. I recognize the images you posted here, as the same as the ones in the BCH, so there is nothing I can add that you don't already know. I was interested to learn that

all red dwarf stars could be potential flare stars. The K60B has one of the smallest stellar masses known too. The 44.6 year period is rapid.

You did not show all the pictures in the BCH catalogue, but the bottom row, actually shows the flare on one of the images. These were taken with the 30" refractor IIRC.

The pair can be separated by a 6" scope with sufficient magnification, but again, you need a close double splitting conducive sky. I think it is fair to say, viewing the pair will be easier than imaging them. Having said that, I hope you continue to try to split them photographically, because I am certain you will succeed, as you will encounter the perfect seeing that will help you do it..

(All the Information here came from Burnham's Celestial Handbook.)

Ron.

[starf]

hi ron, yes the burham books are nice reference material. its sounds impressive when you mention flare stars, until you realise that these stars sit towards the low mass cool end of the hr diagram.

they just look impressive because the star is dim. As kaler says, try to imagine sun-bathing (or dwarf-M-bathing) on the beach and suddenly, with no warning at all, become 10 times brighter.

i think these need more data added so that they dont get strected as much. ive just taken the 4000mm image, reduced the stretch and magnified it 8x and i think there's something there. not bad for a 50sec exposure :-)

i know burnham mentions a 6" scope with high magnification, just how high is anyone's guess but getting closer to finding out.

regards

mike.

[lunator]

Mike

You have caught something there.

Can you put the orientation of the image in N/S/E/W.

Cheers

Ian

[lunator]

HI Mike

Here is the orbit from the 6th orbit catalogue.

WDS Name Grade Reference Theta Rho Theta Rho Theta Rho Theta Rho Theta Rho

2008 2009 2010 2011 2012

22280+5742 KR60AB 2 Hei1986b 46.4 2.140 36.8 2.000 25.9 1.861 13.2 1.726 358.5 1.602

As you can see it is getting tighter. These number relate to Jan 1 of each year so the separation is around 2.06 now. The PA will be around 40 degrees.

I hope this helps.

Cheers

Ian

[starf]

hi ian

thanks for the information. i didnt realise such a catalogue existed. being new to observing these all this information is really helpful. the astrometry seems to tie in well with the catalog. the 4000mm plate resolved at 0.335 pixels/arc sec with a position angle 44.2. the pixel separation is around 6-7 pixels.

the orientation was given in the astrometry data its a bit hard in the jpeg image because north is only approximated. according to the astrometry data up is nearly 9 deg (0-360 CCW). the jpeg and fits are in the same orientation.

SIMPLE = T

BITPIX = 16 /8 unsigned int, 16 & 32 int, -32 & -64 real

NAXIS = 3 /number of axes

NAXIS1 = 1360 /fastest changing axis

NAXIS2 = 1024 /next to fastest changing axis

NAXIS3 = 3

BSCALE = 1.0000000000000000 /physical = BZERO + BSCALE*array_value

BZERO = 0.00000000000000000 /physical = BZERO + BSCALE*array_value

OBJECT = 'do-cep-RGB' / Target object name

TELESCOP = '200mm Newtonian 4000mm' / Telescope name

INSTRUME = 'DSI Pro 3' / Detector instrument name

DATE-OBS = '2008-09-18T21:01:15' / [iSO 8601] UTC date/time of exposure start

EXPTIME = 4.00000000000E+000 / [sec] Duration of exposure

SWMODIFY = 'MaxIm DL Version 4.62' /Name of software that modified the image

HISTORY Plug-in SigmaReject Combine (RC Astro)

CBLACK = 4396 /Initial display black level in ADUs

CWHITE = 7416 /Initial display white level in ADUs

PEDESTAL = 0 /Correction to add for zero-based ADU

INPUTFMT = 'FITS ' / Format of file from which image was read

HISTORY Align Images

HISTORY Color Combine

TIME-OBS = '21:01:15' / [old format] UTC time of exposure start

HISTORY File was processed by PinPoint 5.0.13 at 2008-09-19T15:25:47

EXPOSURE = 4.00000000000E+000 / Duration of exposure

DATE = '18/09/08' / [old format] UTC date of exposure start

UT = '21:01:15' / [old format] UTC time of exposure start

TIMESYS = 'UTC ' / Default time system

RADECSYS = 'FK5 ' / Equatorial coordinate system

CLRBAND = 'R ' / [J-C std] Std. color band of image or C=Color

FWHM = 4.00000000000E+000 / [pixels] Mean Full-Width-Half-Max of image star

ZMAG = 1.97204458359E+001 / Mag zero point for 1 sec exposure

EQUINOX = 2000.0 / Equatorial coordinates are J2000

EPOCH = 2000.0 / (incorrect but needed by old programs)

PA = 8.78761328304E+000 / [deg, 0-360 CCW] Position angle of plate

CTYPE1 = 'RA---TAN' / X-axis coordinate type

CRVAL1 = 3.37057385078E+002 / X-axis coordinate value

CRPIX1 = 6.80000000000E+002 / X-axis reference pixel

CDELT1 = -9.31458135987E-005 / [deg/pixel] X-axis plate scale

CROTA1 = -8.78761328304E+000 / [deg] Roll angle wrt X-axis

CTYPE2 = 'DEC--TAN' / Y-axis coordinate type

CRVAL2 = 5.76853754728E+001 / Y-axis coordinate value

CRPIX2 = 5.12000000000E+002 / Y-axis reference pixel

CDELT2 = -9.29754628611E-005 / [deg/pixel] Y-Axis Plate scale

CROTA2 = -8.78761328304E+000 / [deg] Roll angle wrt Y-axis

CD1_1 = -9.20524151511E-005 / Change in RA---TAN along X-Axis

CD1_2 = -1.42040649484E-005 / Change in RA---TAN along Y-Axis

CD2_1 = 1.42300898034E-005 / Change in DEC--TAN along X-Axis

CD2_2 = -9.18840640872E-005 / Change in DEC--TAN along Y-Axis

HISTORY WCS added by PinPoint 5.0.13 at 2008-09-19T15:25:47

HISTORY Matched 11 stars from the Gray GSC-ACT Catalog

HISTORY Average residual was 0.21 arc-seconds

PLTSOLVD = T / Plate has been solved by PinPoint

regards

mike