[vsnet-alert 9856] Re: HD269858 in unusual state

[Peter F Williams]

Good morning,

For info, attention was directed to the current decline in brightness of
HD269858 in vsnet-alert 9230 of 18 Feb 2007 which included a brief summary
of its visual behaviour from 1983 to that time.

Trust this is of interest.

Tks and regards

Peter Williams
Heathcote NSW

-----Original Message-----
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Ohshima
Sent: Saturday, 26 January 2008 9:16 PM
To: variable_star_forum at yahoogroups.com;
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Subject: [vsnet-alert 9853] HD269858 in unusual state


HDE269858

 According to IAUC 8913, the SDOR type star in LMC HDE269858 seems
to return to a Wolf-Rayet star.
 This star was reported to be a P Cyg star by Cannon, A. J (1933 BHarO,
891, 2) and listed in MWC catalog, which is a catalog of stars showing
 bright hydrogen lines, as MWC511 (Merrill et al. 1943 ApJ 98,153).
In Feast's bright star of the Magellanic clouds, it is reported that
this star was called as R127 and showed P Cyg profile in H-beta and
He4471 (Feast, 1960, MNRAS 121,337).
 Later, this star was known as a Of/WN9 star, which is thought as the
 intermediate state between O star and WN star.

 However, this star underwent an outburst in 1982 (IAUC3767). This
star brightened by ~ 1.5 mag. And this star began to show SDOR type
lines, such as HI, HeI. The spectrum was like a B-type supergiant.
Stahl et al. suggested this star be evolving via a short S Dor phase
 to a late WN star.

 According to AAVSO observations, this star was declining in 1999-2002.
And the spectrum of this star began to change. FeII ,which was strong
around 1986 (B.Wolf et al, A&AS, 1988, 74,239) has weakened.
 Next, this star may return to a Walf-Rayet star.

 According to Breysacher's catalogue (J. Breysacher et al. A&AS 1999,
 137, 117), the position is alpha = 05h36m43.50s delta= -69.29'54".0
(2000.0). Please be careful that this star is near another WR star
R128. Additionally, HDE269858 is in a tight cluster, and it is hard
 to separate these cluster's members.