In 2003.5 Eta Carinae, one of the most luminous and massive stars in the Universe, is expected to undergo an X-ray eclipse. This X-ray eclipse is believed to occur every 5.52 years and is apparently correlated with the 5.52 year fading of high excitation lines (like He II 10830 Å published by Augusto Damineli). The X-ray emission is thought to arise at a shock front produced as the wind from Eta Car slams into the wind from a less massive (but hotter) companion star. The eclipse may be produced as the shock front around the companion moves behind the thick wind of Eta Car. The upcoming eclipse marks only the 3rd time the X-ray eclipse has been seen (the first time was a fortuitous observation with ROSAT), and we hope will mark the first time the event is observed by the full complement of ground-based and space based instrumentation. This page summarizes some of the planned observations, and results as they become available.
See the X-ray Report for more detailed information about the current status of the X-ray observing campaign
The graph below shows the variation of X-ray emission from Eta Car; the red line shows the expected behavior of the observed X-ray emission if the emission were strictly periodic.
The figure below shows the observed RXTE data from a 1-year interval around the eclipse in 1998 (top) and the expected X-ray lightcurve in a 1 year interval around the 2003.5 eclipse (bottom). Note that we already see deviations in the x-ray behavior compared to last cycle - it's not yet clear what effect these deviations will have on the 2003.5 "event".
The discussion of the X-ray observing plan as it stood in July 2001 and as presented by MFC at the Eta Car: Reading the Legend Workshop (Mt. Rainier, WA, July 10-14 2001) is now available.
A) Observation 200219 was observed on October 16, 2002 B) Observation 200215 was observed on May 3, 2003 C) Observation 200218 was observed on Jun 16, 2003 D) Observation 200216 was observed on Jul 20, 2003 D1) Observation 200237 was observed on Aug 28, 2003 E) Observation 200217 was observed on Sep 26, 2003
Date: Mon, 23 Jun 2003 14:08:12 +0200 To: firstname.lastname@example.org, email@example.com Subject: INTEGRAL SCHEDULE NOTIFICATION Dear Integral Observer, Your observation belonging to proposal 0120039 has been scheduled as follows: Start time (UTC) | Source | RA (J2000) | Dec (J2000) 2003-06-24 18:55:33 | eta Carinae | 10:45:03.6 | -59 43 03.0 End time 2003-06-28 08:53:30 Total elapsed duration 200200sec For more details we refer to the Integral short-term plan on the web, available on: http://astro.estec.esa.nl/integral_webapps/index.jsp?future
June 25 Update: The INTEGRAL observation has been split into two 100 ksec observations, one on June 24 and one on July 3 in order to study the variability of the source after the beginning of the X-ray minimum.
See the Eta Car HST Treasury Website at http://etacar.umn.edu
Ted Gull has provided the schedule of HST Treasury observations
The figure on the left shows (approximately) the distribution of STIS observations as a function of X-ray phase, compared to the RXTE X-ray lighcurve. The figure on the right shows the distribution of STIS observations vs. phase compared to 2 published radial velocity curves, one by Damineli et al. (2000) and one by Corcoran et al. (2001).
Date: Sat, 18 Jan 2003 18:33:41 +0200 (SAST) From: Patricia Whitelock
To: "Michael F. Corcoran" cc: MWF , , Patricia Whitelock Subject: Re: Eta Car RXTE monitoring through Jan 15 Hi Mike I expect we will be able to monitor eta Car in JHKL as follows: January 21 - 31, February 1 - 3, 18 - 28, March 1 - 3, 11 - 17, April 15 - 28, May 13 - 19, June 3 - 30. That is the end of the current allocation period. I will apply for time in July as well of course, but will not know about that for a few months. It is our intention to get one JHKL observation per night whenever possible. Regards Patricia -- Dr Patricia Whitelock Acting Director South African Astronomical Observatory P O Box 9 Phone: +27 21 4609318 7935 Observatory Fax: +27 21 4473639 South Africa email: firstname.lastname@example.org
From: "Zulema Abraham" Subject: Re: Eta CAr is dissapearing at the 7 mm continuum also Date: Mon, 23 Jun 2003 18:34:00 -0200 Hi Mike I will be observing every day, weather allowing Zulema
Date: Wed, 21 May 2003 13:36:07 -0400 (EDT) From: Stephen White
Subject: Eta's radio light curve The 8 GHz radio light curve and movie at http://www.astro.umd.edu/~white/images/eta_time_full.html have been updated for an Australia Telescope Compact Array observation last week (the observation was shorter than usual so the image is not quite as good as the others). The radio flux continues to be markedly lower than at the same stage of the previous cycle and may bottom out below the last minimum, but possibly not below the previous minimum. Observations are now possible at 22 GHz as well, and the preliminary images show in addition to the main source identified with the star/s a bright second source 0.5 arcsec to the west-north-west. Stephen White, Bob Duncan, Jessica Chapman and Baerbel Koribalski.
Date: Wed, 17 Apr 2002 18:31:58 -0400 (EDT) From: Stephen White Subject: radio evolution of Eta X-Sun-Charset: US-ASCII We have updated the radio light curve and movie for Eta Carinae at http://www.astro.umd.edu/~white/images/eta_time_full.html with the most recent observation being last week. The radio flux is about half what it was at the same stage of the previous cycle: we interpret this as less ionizing flux getting out to the outflowing gas on this side of the system. Stephen White and Bob Duncan
From: "Augusto Damineli"
Subject: Recent spectra of eta Carinae Date: Wed, 21 May 2003 13:15:49 -0300 Dera eta fans, I put results of new spectra from eta Car collected at LNA/Brazil on 12-15/May. The event is progressing smoothly, as can be seen at: www.etacarinae.iag.usp.br (click on "The 2003.5 event") The radial velocity of HeI 6678 broad component shows short scale flictuations. I have more data to reduce and check this. Augusto
From: Virpi Niemela Subject: Eta Car optical imaging Date: Thu, 23 Jan 2003 14:22:10 -0300 (ART) Hi Mike, I have enrolled graduate and undergraduate students for the Eta Car observing campaign. Weather permitting, they will be monitoring Eta Car during next weekend, when XMM will also observe Eta.... Also CASLEO observers have obtained spectra, high resolution (blue) last week and low resolution (red) this week. cheers, VirpiThe web page http://lilen.fcaglp.unlp.edu.ar/EtaCar/ summarizes the optical observations of Eta Car from the La Plata Observatory
(PI Kerstin Weis, CoIs O. Stahl, D. Bomans, K. Davidson, R. Humphreys, T. Rivinius, Ted Gull, A. Kaufer) With the ESO VLT telescope and the UVES spectrograph, we obtain long-slit, high spatial and high spectral resolution (40,000) spectra of eta Car and its ejecta during the 2003.5 event. The spectra cover in two setting almost the full optical spectral range. The aim is to obtain high-quality long-slit observations along the major axis, critical for understanding the latitude dependence of the star's bimodal wind during the event. We monitor the changes in the central object via the reflected light of the star (or stellar wind) along the major axis of the Homunculus, including region FOS4. We obtain data at approximately one month intervals beginning in December 2002, and at about one week intervals close to the event. For each observation the slit is aligned parallel to the major axis of the Homunculus and passing through FOS 4 which is about 4 arcseconds SE of the central star. A few observations also include a second position with the slit passing directly through the central star.