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havaintotornit-l@ursa.fi
viestiarkisto
Tämä havaintotornit-l@ursa.fi-listan viestiarkisto. Huomaa,
että voit vastata viesteihin tältä sivulta ainoastaan, jos olet jo
liittynyt listalle.
Perjantain ja lauantain välisenä yönä olisi mahdollisuus osallistua
eksoplaneettajahtiin. Alla lisätietoa havaintokampanjasta. Laittakaa
minulle tietoa havaintotuloksista ja -yrityksistä. Annan myös
tarvittaessa havainto-ohjeita. Sääennuste näyttää vain aika
lohduttomalta.
Alkuperäisen viestin liitedokumentteja voi pyytää minulta.
arto
Hi Arto and Veli-Pekka,
I hope that you guys are doing well -- I've had all best intentions to
keep in much better touch after my visit to Finland, so please excuse
my lapse in communications!
I'd like to ask you to spread the news to the network of Finnish
photometric observers of a very interesting upcoming opportunity to
check HD 80606 for a primary transit by its ~4 Mjup planet, HD 80606b.
Using the Spitzer Space telescope, we've discovered that HD 80606b
undergoes a secondary transit. (The results will appear in this week's
issue of Nature, and are currently under "embargo", I've attached the
text of the paper.) Due to the unusual orbital geometry of the HD
80606 system (see attached diagram) this implies a ~15% a-priori
chance that the planet will also be observable in primary transit. The
planet has an orbital period of P=111.4277 days, which would make it
by far the longest-period transiting planet yet detected.
The ephemeris for the transit midpoint is: HJD 2454653.68 +
N(111.4277). The next event is centered at February 14th, 00:50 UT
(HJD 2454876.5354).
If the transit is a central transit, it will last approximately 17
hours. Observations are thus encouraged during an interval of ~15
hours prior to ~15 hours after the predicted midpoint. The uncertainty
in the midpoint time is small. The primary uncertainty is in the
duration of the event, which depends sensitively on the inclination
angle of the planetary orbit.
HD 80606 (V=9.06) RA = 09 22 37.5679; DEC = +50 36 13.397 (ICRS 2000)
has ideal sky position for Northern Hemisphere observers on Feb. 14th,
and is at low airmass from ~19:00 through ~04:00 local time. It is
accompanied by a binary companion, HD 80607, lying 17'' away.
Depending on the observational set-up, this star can either be
combined with the primary, or used as a comparison star.
This system has been the subject of several prior campaigns, but the
accuracy of the ephemeris and the coverage of the observations were
insufficient to either confirm or rule out transits. In light of a
possible 17 hour transit, in order to get a definitive light curve, a
global effort will be required.
Thanks, and best regards,
Greg
Background on the planet:
(1) Discovery Paper: Naef et al. 2001, Astronomy and Astrophysics, 375, L27.
(2) Original (Feb. 2005) AAVSO campaign information:
http://www.aavso.org/news/HD80606.shtml
(3) Oklo.org articles:
http://oklo.org/?p=115 (older)
http://oklo.org/?p=196
http://oklo.org/?p=238
http://oklo.org/?p=239
http://oklo.org/?p=259
http://oklo.org/?p=261 (newer)
(4) Embargoed Nature Manuscript, with the two figures. This can be
circulated to potential observers, but please respect the embargo
(which will be lifted at 1 p.m. US Eastern Time on Jan. 28, 2009).
--
Arto Oksanen
arto.oksanen_at_jklsirius.fi
Muurame, Finland
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