[vsnet-chat 7275] Re: U Mensae

[Stan Walker]

Hi Alan,

I noted the various comments about U Mensae and looked up the star in the GCVS and ASAS. The latter shows a good light curve but flat bottomed due to the presence of a companion (probably line of sight only). GCVS gives a value of 10.4 (photographic, I think) for this and a separation of 0.6". Guide 6 has some values from Tycho but they don't match the GCVS at all. 

The ASAS measures prove that it is a Mira star, but its light curve is dramatically distorted due to the companion star. For more than 50% of the light curve any observer is seeing mainly light from the companion - hence the low amplitude and the incorrect SR classification. Now that Arne has identified the correct star I imagine that there are a few measured stars nearby which could help observing?

Regards,
Stan
  ----- Original Message ----- 
  From: A Plummer 
  To: vsnet-chat at ooruri.kusastro.kyoto-u.ac.jp 
  Sent: Thursday, February 02, 2006 8:15 PM
  Subject: [vsnet-chat 7271] U Mensae


  Dear All,

  Does anyone out there observe, or have a chart, or any info, on U Men? I have been using the AAVSO 'd' chart for a couple of years, and I've not had much sucess with my observations. It is identifiesd as SRa, 407d, 8 - 10.9p mag. The object appears to be plotted correctly, but it has been dim - at least to my eyes - for a couple of years. I've never seen it over 11th mag, and that is way out of the chart's sequence.  Can any one help?

  Thanks. Alan.


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