| Full text | |
| Author(s): |
Damineli, A.
[1]
;
Navarete, F.
[1]
;
Hillier, D. J.
[2, 3]
;
Moffat, A. F. J.
[4, 5]
;
Corcoran, M. F.
[6, 7, 8]
;
Gull, T. R.
[9]
;
Richardson, N. D.
[10]
;
Weigelt, G.
[11]
;
Morris, P. W.
[12]
;
Stevens, I
[13]
Total Authors: 10
|
| Affiliation: Show less - | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, BR-05508090 Sao Paulo, SP - Brazil
[2] Univ Pittsburgh, Dept Phys & Astron, 3941 OHara St, Pittsburgh, PA 15260 - USA
[3] Univ Pittsburgh, Pittsburgh Particle Phys Astrophys & Cosmol Ctr P, 3941 OHara St, Pittsburgh, PA 15260 - USA
[4] Univ Montreal, Dept Phys, CP 6128, Montreal, PQ H3C 3J7 - Canada
[5] Univ Montreal, Ctr Rech Astrophys Quebec CRAQ, CP 6128, Montreal, PQ H3C 3J7 - Canada
[6] Catholic Univ Amer, Inst Astrophys & Computat Sci, Dept Phys, Washington, DC 20064 - USA
[7] NASA, CRESST 2, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 - USA
[8] NASA, Xray Astrophys Lab, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 - USA
[9] NASA, Lab Extraterr Planets & Stellar Astrophys, Goddard Space Flight Ctr, Code 667, Greenbelt, MD 20771 - USA
[10] Embry Riddle Aeronaut Univ, Dept Phys & Astron, 3700 Willow Creek Rd, Prescott, AZ 86301 - USA
[11] Max Planck Inst Radio Astron, Hugel 69, D-53121 Bonn - Germany
[12] CALTECH, IPAC M-C 100-22, Pasadena, CA 10022 - USA
[13] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands - England
Total Affiliations: 13
|
| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 505, n. 1, p. 963-978, JUL 2021. |
| Web of Science Citations: | 0 |
| Abstract | |
Eta Carinae is a massive interacting binary system shrouded in a complex circumstellar environment whose evolution is the source of the long-term brightening observed during the last 80 yr. An occulter, acting as a natural coronagraph, impacts observations from our perspective, but not from most other directions. Other sight-lines are visible to us through studies of the Homunculus reflection nebula. The coronagraph appears to be vanishing, decreasing the extinction towards the central star, and causing the star's secular brightening. In contrast, the Homunculus remains at an almost constant brightness. The coronagraph primarily suppresses the stellar continuum, to a lesser extent the wind lines, and not the circumstellar emission lines. This explains why the absolute values of equivalent widths (EWs) of the emission lines in our direct view are larger than those seen in reflected by the Homunculus, why the direct view absolute EWs are decreasing with time, and why lower-excitation spectral wind lines formed at larger radii (e.g FeII 4585 angstrom) decrease in intensity at a faster pace than higher excitation lines that form closer to the star (e.g. H delta). Our main result is that the star, despite its 10-fold brightening over two decades, is relatively stable. A vanishing coronagraph that can explain both the large flux evolution and the much weaker spectral evolution. This is contrary to suggestions that the long-term variability is intrinsic to the primary star that is still recovering from the Great Eruption with a decreasing mass-loss rate and a polar wind that is evolving at a slower pace than at the equator. (AU) | |
| FAPESP's process: | 11/51680-6 - Exploring the universe: from the galaxies formation to Earth-like planets with the Giant Magellan Telescope |
| Grantee: | Laerte Sodré Junior |
| Support Opportunities: | Special Projects |
| FAPESP's process: | 19/02029-2 - Eta Carinae: a perfect periastron passage in 2020 |
| Grantee: | Augusto Damineli Neto |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 17/18191-8 - High-mass star formation: the mass of the central sources and the physics of the accretion process |
| Grantee: | Felipe Donizeti Teston Navarete |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |