Radio Galaxy Zoo Talk

on the nature of 1RXS X-ray images and their relation to visible wavelengths

  • planetaryscience by planetaryscience

    I suppose this would be a useful place to put this- looking at http://wikisky.org images in x-ray and visual wavelengths, I noticed that X-rays from the survey appeared to come in three colors; orange, white, and blue. I believe these correspond to low energy, medium energy, and high energy X-rays. Looking at them, I noticed that orange X-rays almost always corresponded with white dwarf stars, and in some cases with low-mass binaries. In medium-energy X-rays (white) I found most of the objects to be binary stars in close orbits or apparent variable stars, such as Capella, Algol, HD 17433, HD 21242, and HD 22403. Then in blue X-rays I found high-mass stellar remnants (like neutron stars and black holes) in binary orbits, or galaxies with active galactic nuclei. I don't know where else to post this, but I thought it may be of use.

    I also used it to find an object with a high proper motion, and in a binary (possibly trinary) orbit near the apparent position of the galactic core - known only as 2MASS J18352154-3123385. The stars both have proper motions of approximately half an arcsecond a year, and an unknown distance. However based on the proper motion, it might be less than 50 light years away.

    Anyways, are these well-known facts? If not, they could be potentially important to the study of stars, white dwaves, and active galactic nuclei.

    Posted

  • ivywong by ivywong scientist, admin

    Thank you very much @planetaryscience!

    While we do not expect many stars in Radio Galaxy Zoo, the X-ray information from wikisky may be useful for RGZooites who are interested or curious about the X-ray emission of some fo the AGN that they are investigating in RGZ.

    We are ~8 kpc from the core of our Galaxy and our central black hole is called Sagittarius A*. I am not sure I understand what you mean by 50 light years away. Do you mean that the object with high proper motion is 50 light years from us ?

    Posted

  • planetaryscience by planetaryscience

    The object appears to be about 50 light years away, due to its high proper motion, almost as high as that of known nearby star, in the vicinity of 2MASS J18352154-3123385, Ross 154. Their angular proper motions are 510 +19 -13 mas and 665 +/- 3 mas. This puts 2MASS J18352154-3123385 only slightly further away.

    The object, despite its apparent vicinity, appears not to have been noticed because it is so close to the apparent position of the galactic core.

    Looking at the below image, it isn't exactly easy to discern which object it is.

    enter image description here

    It's this star by the way:

    enter image description here

    Based on its proper motion, assuming a distance of 15-20 light years, and given a magnitude of 12 and 12.5 respectively, the stars have absolute magnitudes of 13.0-13.7 and 13.5-14.2, which puts the two stars at the lower end of the main sequence, possibly M5 and M8 dwarfs. The provided J, H, and K magnitudes, and the assumed V magnitudes put the primary's spectral type at M8 (V-J), M7 (V-H), and M6 (V-K). Similarly J, H, and K magnitudes put it at late K/early M-type.

    As all of these are in near-agreement, I arrive at a rough distance of the object to the Sun of 25 +/- 5 light years.

    Posted

  • ivywong by ivywong scientist, admin

    Thanks @planetaryscience! OK, if I'm understanding correctly, you think this star is 25 light years from the Sun and it's close in projection to the Galactic core. So where did the 50 light years come from?

    Posted

  • planetaryscience by planetaryscience

    I did a preliminary estimate of 50 light years based solely on its apparent proper motion, but taking into account more specific measurements such as its spectral type I know it to be a visual binary system of type ~M6.5 and ~M8 stars, orbiting each other in greater than 8 years, but likely less than 20. The stars orbit each other on a plane almost directly across our line of sight, forming a possible eclipsing binary system. Additionally, the primary is either itself a binary (which is unlikely due to the clear instability of such a system) or a flare star (which is significantly more likely, as M-dwarfs are frequently flare stars). A measurement of ~25 light years puts it something around the 100th or 200th closest known star to the Sun, with an estimated parallax of about 130 milliarcseconds.

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Am I right and you are talking about this?

    DSS2 Red 1'x1'

    enter image description here

    Center is 2MASS 18352154-3123385 aka USNO B1 - 0586-0756397

    "The star"

    Is 2MASS 18352205-3123421 aka GSC S9VH029522

    J-H = 0,623

    H-K = 0.282

    Posted

  • planetaryscience by planetaryscience

    Yes, those are the stars, and I've been trying to look at VizieR images of the objects to determine their orbital period, but it appears their motion is mostly linear, so it might be that they have recently reached their closest apparent separation, and that they might orbit much further from one another. However of course more observations would be required to determine much more about these stars, if anyone has a big enough telescope below 60 degrees north?

    Posted