[vsnet-chat 1776] Re: (fwd) object identification request

[Taichi Kato <tkato>]

Re: [vsnet-chat 1773] Re: (fwd) object identification request

  For readers who haven't followed messages in vsnet-obs, I repeat the
relevant messsages (in replying, please cc: to rwb0006@jove.acs.unt.edu).

Subject: [vsnet-obs 20138] (fwd) object identification request

   Looks like a flash from a satellite.  Could someone suggest?

>From owner-vsnet-adm@kusastro.kyoto-u.ac.jp Fri Apr 16 16:02 JST 1999
Date: Fri, 16 Apr 1999 02:01:31 -0500 (CDT)
From: Robert Warren Brown <rwb0006@jove.acs.unt.edu>
To: vsnet-adm@kusastro.kyoto-u.ac.jp
cc: skyline@corvus.com, majordomo@latrade.com, astronews@geocities.com,
        majordomo@mindspring.com, aavso-discussion-request@physics.mcmaster.ca,
        saul@lbl.gov
Subject: ****Possible Nova****

To all interested parties.  I am an amateur astronomer located in Denton
Texas.  This evening as I was teaching a astronomy class at the University
of North Texas observatory, I witnessed what may be a nova.  I noticed
that a real bright star was in a location that I have never noticed.  I
was looking at it trying to figure out what it was because it was so
bright. ( greater than -2 mag.) This was in the constellation Ursa Major
approximate RA was 9hr 50min, dec 59.  I think the star was Upsilon Ursae
Majoris, SAO # 27401.  In any case, the object was very bright and as I
came to realize how out of place it was, it began to dim.  When I first
noticed this object it was far brighter than any of the primary stars in
the dipper!  As I watched in the span of a few seconds, this object dimmed
to less than +3 mag by my estimate. 

 I trained a scope on it and could not add anything except a possible
fuzzyness that may be due to atmospheric conditions here in the area. 
This occured at approximately 12:43AM Central.
Approx.Julian Date: 2451284.73 by my calculations.
RA 9hr 50 min Dec +59 degrees

I obviously would like some confirmation on this sighting.
Sincerly
Robert W. Brown
(940)383-5961
Denton Texas

Subject: [vsnet-obs 20141] Re: (fwd) object identification request

>From rwb0006@jove.acs.unt.edu Fri Apr 16 16:19 JST 1999
Date: Fri, 16 Apr 1999 02:19:10 -0500 (CDT)
From: Robert Warren Brown <rwb0006@jove.acs.unt.edu>
To: Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>
Subject: Re: (fwd) object identification request


On Fri, 16 Apr 1999, Taichi Kato wrote:

> 
>    Looks like a flash from a satellite.  Could someone suggest?

Possibly, except that this was close to midnight in this region of the
world.  A satellite would normally require reflected sunlight. Unless it
is a satellite of a high geosyncronous orbit, I do not believe that the
sun could have reached it.  Also the object was stationary and dimmed to a
constant brightness.  I believe it was SAO number 27401.
-Robert Brown

> 
> >From owner-vsnet-adm@kusastro.kyoto-u.ac.jp Fri Apr 16 16:02 JST 1999
> Date: Fri, 16 Apr 1999 02:01:31 -0500 (CDT)
> From: Robert Warren Brown <rwb0006@jove.acs.unt.edu>
> To: vsnet-adm@kusastro.kyoto-u.ac.jp
> cc: skyline@corvus.com, majordomo@latrade.com, astronews@geocities.com,
>         majordomo@mindspring.com, aavso-discussion-request@physics.mcmaster.ca,
>         saul@lbl.gov
> Subject: ****Possible Nova****
> 
> To all interested parties.  I am an amateur astronomer located in Denton
> Texas.  This evening as I was teaching a astronomy class at the University
> of North Texas observatory, I witnessed what may be a nova.  I noticed
> that a real bright star was in a location that I have never noticed.  I
> was looking at it trying to figure out what it was because it was so
> bright. ( greater than -2 mag.) This was in the constellation Ursa Major
> approximate RA was 9hr 50min, dec 59.  I think the star was Upsilon Ursae
> Majoris, SAO # 27401.  In any case, the object was very bright and as I
> came to realize how out of place it was, it began to dim.  When I first
> noticed this object it was far brighter than any of the primary stars in
> the dipper!  As I watched in the span of a few seconds, this object dimmed
> to less than +3 mag by my estimate. 
> 
>  I trained a scope on it and could not add anything except a possible
> fuzzyness that may be due to atmospheric conditions here in the area. 
> This occured at approximately 12:43AM Central.
> Approx.Julian Date: 2451284.73 by my calculations.
> RA 9hr 50 min Dec +59 degrees
> 
> I obviously would like some confirmation on this sighting.
> Sincerly
> Robert W. Brown
> (940)383-5961
> Denton Texas
> 

Subject: [vsnet-obs 20142] Re: (fwd) object identification request

> Possibly, except that this was close to midnight in this region of the
> world.  A satellite would normally require reflected sunlight. Unless it
> is a satellite of a high geosyncronous orbit, I do not believe that the
> sun could have reached it.  Also the object was stationary and dimmed to a
> constant brightness.

    The obvious lack of apparent motion is consistent with a high orbit
(if not geosyncronous).  I expect some expert on satellite identifications
can provide an identification.  SAO 27401 = Upsilon UMa is a low-amplitude
delta Sct-type variable star.  If the event is indeed related to this star,
this should be very unexpected.

Regards,
Taichi Kato

Subject: [vsnet-obs 20144] Re: (fwd) object identification request

> Thank-you for the replies.  I am unsure of how to proceed.  I have sent
> out a number of e-mails to other possibly interested parties.  Could you
> send me an e-mail address of a nova alert group?.... just in case.

   This is not a nova (at least in any sense of our knowledge in astronomy).
We have been operating a (nova) alert network, a sub-list of which I have
fowarded your message to. (Formerly there was a nova-dedicated network called
Nova Net, but is not working now).  Of course, you can post directly by
yourself to some of VSNET list.

   I strongly suspect (unless remains unidentified with a satellite) that
the flare was caused by a satellite.  I would encourage you to consult
satellite specialist group (but I don't know who to contact, since we mostly
deal with extra-solar system objects) for more accurate identification.

Regards,
Taichi Kato

Subject: [vsnet-obs 20146] Re: (fwd) object identification request

> Of course it could be a satellite. However,I have never observed a
> stationary satellite changing brightness to the degree that I mentioned. 
> Also the observed object remained at a steady apparent magnitude for some
> time after it's episode.  Additionally,the max.  brightness was far in
> excess of Arcturus.  The manner in which it dimmed was at a steady rate
> until it reached a constant apparent magnitude.  I also have no
> explanation

    I have heard (from popular astronomy magazines) very similar brightening
events have been identified with satellite flares.  The present satellite
ephemeris is accurate enough to locate which satellite could be at the
position noted.  I myself have seen several times satellites brightening
to -2 mag or brighter without an apparent motion, but the nature was soon
revealed by examining by a binocular.  The motion of the satellite can be
slow enough for unaided human eyes to recognize.  The brightening and dimming
pattern differs from satellite to satellite; some of which show short
flash-like flares (e.g. Iridium satellites), others show slower brightening
and fading.  Before proceeding to the possibility of stellar origin, I'd
recommend you to rule out all possibilities of existing satellites.

Regards,
Taichi Kato

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