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(meteorobs) Fwd Re: Phaeton directly imaged or spectrographed?
[Forwarded without permission of the author. -Lew Gramer]
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Date: Thu, 20 Aug 1998 10:48:53 +0200 (MET DST)
From: PRAVEC Petr <ppravec@sunkl.asudot cas.cz>
To: "E. L. G. Bowell" <elgb@lowelldot edu>, mplist@bitnik.com
Subject: Re: Phaeton directly imaged or spectrographed?
On Wed, 19 Aug 1998, E. L. G. Bowell wrote:
> The only physical data on 3200 Phaeton were published by Wisniewski et al.
> (Icarus 126, 395, 1997), in which a lightcurve period of 4.08 +/- 0.08 hr is
> given. I don't think any colorimetry or spectroscopy has been published.
I and my colleagues have derived a period of 3.57 +/- 0.02 hr from
our Phaethon lightcurve observations of 1997 Nov. 1 and 2 (Icarus,
in press). K. Meech has also presented her and her colleagues'
results on Phaethon at the ACM 96 conference in Versailles;
in abstract of her talk, a period of 3.604 +/- 0.0011 hr is given,
that is based on a 9-day observational interval. It appears
that the Phaethon's period is shorter than any known comet rotation
periods that I found in literature. (Can anyone tell me if (s)he
knows a similarly short rotation period of a comet?) A significance of
this result is that it indicates that Phaethon's internal structure may
be different from that of normal cometary nuclei. (It may have a greater
bulk density.)
>Phaeton is indeed a shy creature. For the next few apparitions it reaches
>its brightest in conjunction with the Sun, barely peeping above V = 17 mag
>at observable solar elongations. The next bright apparition is in 2008
>(V = 13 mag, elongation = 110 deg). You can check out observability of
>asteroids at one of the Lowell Observatory web sites:
> http://asteroid.lowelldot edu/cgi-bin/koehn/obs.
> Regards...Ted Bowell
Best regards,
Petr Pravec
Ondrejov Observatory (code 557)
Czech Republic
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