Observatorio Astronómico de La Plata

Facultad de Ciencias Astronómicas y Geofísicas
Universidad Nacional de La Plata


Optical monitoring of Eta Carinae

Last data update: abr 14, 2014
2014 Observing season has started!!

Introduction

Eta Carinae is one of the most massive and luminous stars in our galaxy, and is suspected to be a binary system with a period of 5.54 years. In 2003.5 it was expected to undergo an X-ray eclipse. In the framework of an international campaign to obtain multi-wavelength observations of this event (see details) we began an optical CCD monitoring of Eta Carinae. This event was detected with our photometry as a kind of "eclipse" (Fernández-Lajús et al., 2003, IBVS, 5477, 1). Our optical monitoring has already completed the light curves during a whole orbital period (Fernández-Lajús et al., 2009, A&A, 493, 1093) and detected the 2009.0 "eclipse-like" event (Fernández-Lajús et al., 2010, New Astronomy, 15, 108). The latest results and news related with this event have been presented at the IAU Joint Discussion 13 "Eta Carinae in the Context of the Most Masstive Stars" (Rio de Janeiro, 13-14 August 2009). The post 2009.0-event data are also available at Fernández-Lajús et al., 2009, IBVS, 5915, 1. The complete and most recent BVRI and Halpha light curves of Eta Car are presented in this page.


Present status

  • Apr 11, we are back!!!
  • The CCD camera is out of order since Feb 21, 2011.
  • The Halpha light curves will be monthly updated in this page since Dec 10, 2009.
  • Davidson, Mehner and Martin (IAUC9094, Nov. 11, 2009) report that the innermost central region (r < 0.15 arcsec) of Eta Car increased 0.5 mag in mid-2009. This tendecy is in agreement with our results on the both last events (see the plot below).
  • Eta Car is brightening again, Aug. 12, 2009.
  • A new maximum has peaked around Jul. 14, 2009.
  • Eta Car continues increasing its brightness (Jun. 29, 2009).
  • Eta Car has temporarily stopped or slowed down its rising trend after the periastron minimum, about Mar. 05, 2009.
  • Eta Car has arrived to the level of minimum about Jan. 26-27, 2009, and rising again.
  • Jan. 16, 2009: Eta Car reached the maximum at different dates for each band as follows: B on Jan. 15, V on Jan. 12, R on Jan. 3, and I on Jan. 9.

    BVRI Halpha differential photometry of Eta Carinae






    Individual measurements


    V-relative brigthness increasing of the central region, relative to the complete Homunculus just after events


    Observations

    CCD observations are made using the 0.8 m "Virpi Niemela" telescope, at La Plata Observatory.
    Differential photometry of Eta Car is determined using HDE303308 as comparison star. Approximate standard magnitudes of Eta Car are estimated using the UBVRI (Johnson-Kron-Cousins) photometry data (Feinstein, 1982) as zero-points.

    Right: color composite of B, V and R images adquired on May 08-09, 2006 (Seeing ~ 1.5").

    1- Eta Car,
    2- HDE 303308 (Tr16-7),
    3- CPD -59 2628 (Tr16-1),
    4- CPD -59 2627 (Tr16-3)


    Observing Seasons
    Year: From: Up-to: + 2003 20/01/03 29/08/03 + 2004 14/11/03 30/08/04 + 2005 17/11/04 30/08/05 + 2006 16/11/05 29/08/06 + 2007 13/11/06 31/08/07 + 2008 23/11/07 31/08/08 + 2009 12/11/08 25/08/09 + 2010 01/12/09 05/09/10 + 2011 15/11/10 14/09/11 + 2012 11/11/11 14/09/12 + 2013 04/01/13 11/06/13


    Visual historical light curve of Eta Carinae


    This light curve depicts the visual apparent brightness of Eta Car since 1822 up to date. It is based on the references given by Fernández-Lajús et al. (2009, A&A, 493, 1093), and the present observations. It contains visual estimates (big circles), photographic (squares), photoelectric (triangles) and CCD (small circles) observations through different visual filters and photometric systems. All of them have been fitted for consistency of the whole data. Red points are observations from La Plata (Feinstein 1967; Fernández-Lajús et al. 2009a, 2009b, 2010). New CCD data obtained from RXTE Star Tracker has been ploted to complete the gap in the light curve before 2003 (Craig Markwardt & Mike Corcoran, private comunication, 2009).


    Publications


    Media articles:


    Interesting Links:

    Simbad identification
    Bibliography on Eta Car (link to ADS).
    Form for reportings to IAU Circulars


    Other interesting sites related:


    A. Damineli's page


    Evolution in radio (8.585GHz).


    HST Treasury Project.




    VLT (ESO) page.


    AAVSO page.





    Mike Corcoran's page


    Chandra album.





    Some history...


    Related works:

    Observations of the eclipsing binary CPD-59 2628 (Tr16#1).


  • La Plata Eta Car working group

  • Contact: Eduardo Fernández Lajús: eflajus@fcaglp.unlp.edu.ar


    Counter Stats since 15/06/06
    self storage

  • Web-page: Eduardo Fernández-Lajús
    Last page update: 22/12/2009