The Chrysalis Opens? Photometry from the ? Carinae<i>Hubble Space Telescope</i>Treasury Project, 2002?20061,2

Martin, John; Davidson, Kris; Koppelman, M. D.

doi:10.1086/508933

Cited by 44 publications

(77 citation statements)

References 32 publications

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“…In the optical band, the brightness of η Car increased by several magnitudes during the last ∼30 years (see Fernández-Lajús et al 2009;Gomez et al 2010;Smith & Frew 2011). This increasing optical brightness suggests that the inner envelope, that enshrouds the central star, is currently opening up (Martin et al 2006), and a larger fraction of the stellar optical and UV radiation, that was previously absorbed within the nebula and thus heated the dust, is now able to leave the system. As a consequence, the fraction of the stellar radiation that is absorbed and heats the dust in the envelope decreases.…”

Section: The Far-infrared Spectral Energy Distribution Of η Carinaementioning

confidence: 99%

“…In the optical, it once represented the second brightest star on the sky, A67, page 13 of 18 but faded by more than eight magnitudes between 1850 and 1880. During the last three decades, it brightened by several magnitudes (Martin et al 2006;Smith & Frew 2011). Strong X-ray variability is seen as a result of dynamical changes in the wind collision zone (Corcoran et al 2010).…”

Section: The Far-infrared Spectral Energy Distribution Of η Carinaementioning

confidence: 99%

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Herschelfar-infrared observations of the Carina Nebula complex

Gaczkowski

Preibisch

Ratzka

et al. 2012

A&A

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Context. The Carina Nebula represents one of the largest and most active star forming regions known in our Galaxy. It contains numerous very massive (M > ∼ 40 M ) stars that strongly affect the surrounding clouds by their ionizing radiation and stellar winds. Aims. Our recently obtained Herschel PACS and SPIRE far-infrared maps cover the full area (≈8.7 deg 2 ) of the Carina Nebula complex (CNC) and reveal the population of deeply embedded young stellar objects (YSOs), most of which are not yet visible in the mid-or near-infrared. Methods. We study the properties of the 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands. For those objects that can be identified with apparently single Spitzer counterparts, we use radiative transfer models to derive information about the basic stellar and circumstellar parameters. Results. We find that about 75% of the Herschel-detected YSOs are Class 0 protostars. The luminosities of the Herschel-detected YSOs with SED fits are restricted to values of ≤5400 L , their masses (estimated from the radiative transfer modeling) range from ≈1 M to ≈10 M . Taking the observational limits into account and extrapolating the observed number of Herschel-detected protostars over the stellar initial mass function suggest that the star formation rate of the CNC is ∼0.017 M /year. The spatial distribution of the Herschel YSO candidates is highly inhomogeneous and does not follow the distribution of cloud mass. Rather, most Herschel YSO candidates are found at the irradiated edges of clouds and pillars. The far-infrared fluxes of the famous object η Car are about a factor of two lower than expected from observations with the Infrared Space Observatory obtained 15 years ago; this difference may be a consequence of dynamical changes in the circumstellar dust in the Homunculus Nebula around η Car. Conclusions. The currently ongoing star formation process forms only low-mass and intermediate-mass stars, but no massive (M > ∼ 20 M ) stars. The characteristic spatial configuration of the YSOs provides support to the picture that the formation of this latest stellar generation is triggered by the advancing ionization fronts.

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Section: The Far-infrared Spectral Energy Distribution Of η Carinaementioning

confidence: 99%

Section: The Far-infrared Spectral Energy Distribution Of η Carinaementioning

confidence: 99%

Herschelfar-infrared observations of the Carina Nebula complex

Gaczkowski

Preibisch

Ratzka

et al. 2012

A&A

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“…We have monitored the brightness changes of the central star in several band-passes with photometry from HST ACS/HRC and WFPC2 images and STIS spectra since 1998 (Martin & Koppelman 2004;Martin et al 2006bMartin et al , 2010. During the 2009 event we monitored the brightness of the central star with the HST WFPC2 camera using the F255W and F336W filters.…”

Section: Hst Photometry With Wfpc2 and Stismentioning

confidence: 99%

“…′′ 3 diameter weighted aperture following procedures described in our previous papers which, combined with the spatial resolution of the HST, minimize the influence from nearby bright ejecta. ACS-equivalent photometry was also synthesized from HST STIS data before mid-2004 and after mid-2009; spectra were extracted with a weighted parabolic cross dispersion profile similar to the virtual aperture used to measure ACS/HRC images, convolved with the filter functions, and integrated (Martin et al 2006b). The WFPC2 photometry from 2008.7 to 2009.3 and STIS synthetic photometry from 2009.6 to 2010.6 is listed in Table 1.…”

Section: Hst Photometry With Wfpc2 and Stismentioning

confidence: 99%

Critical Differences and Clues in Eta Car's 2009 Event,

Mehner

Davidson²,

Martin

et al. 2011

ApJ

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105

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We monitored Eta Carinae with HST WFPC2 and Gemini GMOS throughout the 2009 spectroscopic event, which was expected to differ from its predecessor in 2003). Here we report major observed differences between events, and their implications. Some of these results were quite unexpected. (1) The UV brightness minimum was much deeper in 2009. This suggests that physical conditions in the early stages of an event depend on different parameters than the "normal" inter-event wind. Extra mass ejection from the primary star is one possible cause. (2) The expected He II λ4687 brightness maximum was followed several weeks later by another. We explain why this fact, and the timing of the λ4687 maxima, strongly support a "shock breakup" hypothesis for X-ray and λ4687 behavior as proposed 5-10 years ago. (3) We observed a polar view of the star via light reflected by dust in the Homunculus nebula. Surprisingly, at that location the variations of emission-line brightness and Doppler velocities closely resembled a direct view of the star; which should not have been true for any phenomena related to the orbit. This result casts very serious doubt on all the proposed velocity interpretations that depend on the secondary star's orbital motion. (4) Latitude-dependent variations of H I, He I and Fe II features reveal aspects of wind behavior during the event. In addition, we discuss implications of the observations for several crucial unsolved problems.

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“…Nuclear processed material from the core reaches the outer layers and eventually is ejected from the star. transition began in the 1990s (Humphreys et al 1999;Martin et al 2006;Mehner et al 2010;Humphreys & Martin 2012 and other references therein)-almost hinting at a 50-year quasiperiodicity. Many authors have speculated that these peculiarities have something to do with the companion star, because tidal effects may be appreciable in the primary's windacceleration zone.…”

Section: Summary and Discussionmentioning

confidence: 97%

Recovery From Giant Eruptions in Very Massive Stars

Kashi

Davidson

Humphreys

2016

ApJ

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We use a hydro-and-radiative-transfer code to explore the behavior of a very massive star (VMS) after a giant eruption-i.e., following a supernova impostor event. Beginning with reasonable models for evolved VMSs with masses of 80M e and 120M e , we simulate the change of state caused by a giant eruption via two methods that explicitly conserve total energy. (1) Synthetically removing outer layers of mass of a few M e while reducing the energy of the inner layers. (2) Synthetically transferring energy from the core to the outer layers, an operation that automatically causes mass ejection. Our focus is on the aftermath, not the poorly understood eruption itself. Then, using a radiation-hydrodynamic code in 1D with realistic opacities and convection, the interior disequilibrium state is followed for about 200 years. Typically the star develops a ∼400 km s −1 wind with a mass loss rate that begins around 0.1M e yr −1 and gradually decreases. This outflow is driven by κ-mechanism radial pulsations. The 1D models have regular pulsations but 3D models will probably be more chaotic. In some cases a plateau in the massloss rate may persist about 200 years, while other cases are more like η Car which lost >10M e and then had an abnormal mass loss rate for more than a century after its eruption. In our model, the post-eruption outflow carried more mass than the initial eruption. These simulations constitute a useful preliminary reconnaissance for 3D models which will be far more difficult.

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The Chrysalis Opens? Photometry from the ? CarinaeHubble Space TelescopeTreasury Project, 2002?20061,2

Cited by 44 publications

References 32 publications

Herschelfar-infrared observations of the Carina Nebula complex

Herschelfar-infrared observations of the Carina Nebula complex

Critical Differences and Clues in Eta Car's 2009 Event,

Recovery From Giant Eruptions in Very Massive Stars

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