A third cluster of red supergiants in the vicinity of the massive cluster RSGC3

González-Fernández, C.; Negueruela, I.

doi:10.1051/0004-6361/201118090

Cited by 33 publications

(12 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following Fig. 2 in González-Fernández & Negueruela (2012), the CO EW ≈ 11 Å of CEN 34 suggests an early-K giant or mid-G supergiant, and the latter agrees well with the previously classified spectral type and luminosity class, if the involved uncertainty is considered.…”

Section: Co Bandhead Absorptionsupporting

confidence: 86%

CEN 34 – high-mass YSO in M 17 or background post-AGB star?

Chen

Nürnberger

Chini

et al. 2013

A&A

View full text Add to dashboard Cite

We investigate the proposed high-mass young stellar object (YSO) candidate CEN 34, thought to be associated with the star-forming region M 17. Its optical to near-infrared (550−2500 nm) spectrum reveals several photospheric absorption features, such as Hα, the Ca ii triplet, and the CO bandhead, but lacks emission lines. The spectral features in the range 8375−8770 Å are used to constrain an effective temperature T eff = 5250 ± 250 K (early-/mid-G) and a log g = 2.0 ± 0.3 (supergiant). The spectral energy distribution (SED) displays a faint infrared excess that resembles that of a high-mass YSO or an evolved star of intermediate mass. Moreover, the observed temperature and surface gravity are identical for high-mass YSOs and evolved stars. The radial velocity of CEN 34 relative to the local standard of rest (V LSR ) as obtained from various photospheric lines is of the order of −60 km s −1 and thus distinct from the +25 km s −1 found for several OB stars in the cluster and for the associated molecular cloud. The SED modeling yields ∼10 −4 M of circumstellar material, which contributes only a tiny fraction to the total visual extinction (11 mag). The distance of CEN 34 is between 2.0 kpc and 4.5 kpc. In the case of a YSO, a dynamical ejection process is proposed to explain the V LSR difference between CEN 34 and M 17. Additionally, to match the temperature and luminosity, we speculate that CEN 34 had accumulated the bulk of its mass with an accretion rate >4 × 10 −3 M /yr over a very short time span (∼10 3 yrs), and it is currently undergoing a phase of gravitational contraction without any further mass gain. However, all the aforementioned characteristics of CEN 34 are compatible with an evolved star of 5−7 M and an age of 50−100 Myr, so it is most likely a background post-AGB star with a distance between 2.0 kpc and 4.5 kpc. We consider the latter classification as the more likely interpretation. Further discrimination of the two possible scenarios should come from the stricter confinement of CEN 34's distance.

show abstract

Section: Co Bandhead Absorptionsupporting

confidence: 86%

CEN 34 – high-mass YSO in M 17 or background post-AGB star?

Chen

Nürnberger

Chini

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…The EW of CO bandhead increases linearly with temperature declining for giants and supergiants, respectively, and the latter has higher EW than the former of the same effective temperature (e.g., González-Fernández & Negueruela 2012). The CO bandhead of B273A coincides in depth and width with that of the reference star, a G4 giant (see Fig.…”

Section: Sinfoni Near-ir Spectroscopy Of Point Sourcesmentioning

confidence: 76%

“…of CO bandhead for B273A to be ≈3.5 Å, which suggests a spectral type of G4/G5 for a giant and G2/G3 for a supergiant when following Fig. 2 in González-Fernández & Negueruela (2012). Alternatively, we checked the EW of CO bandhead for the main-sequence stars catalogued by Wallace & Hinkle (1997) and found that B273A's CO bandhead strength is between that of a G8 V (HR 4496) and a K2 V (HR 1084) star.…”

Section: Sinfoni Near-ir Spectroscopy Of Point Sourcesmentioning

confidence: 97%

VLT near- to mid-IR imaging and spectroscopy of the M 17 UC1 – IRS5 region

Chen

Nürnberger

Chini

et al. 2015

A&A

View full text Add to dashboard Cite

Aims. We investigate the surroundings of the hypercompact H ii region M 17 UC1 to probe the physical properties of the associated young stellar objects and the environment of massive star formation. Methods. We use diffraction-limited near-IR (VLT/NACO) and mid-IR (VLT/VISIR) images to reveal the different morphologies at various wavelengths. Likewise, we investigate the stellar and nebular content of the region with VLT/SINFONI integral field spectroscopy with a resolution R ∼ 1500 at H + K bands. Results. Five of the seven point sources in this region show L-band excess emission. A geometric match is found between the H 2 emission and near-IR polarized light in the vicinity of IRS5A, and between the diffuse mid-IR emission and near-IR polarization north of UC1. The H 2 emission is typical for dense photodissociation regions (PDRs), which are initially far-ultraviolet pumped and repopulated by collisional de-excitation. The spectral types of IRS5A and B273A are B3−B7 V/III and G4−G5 III, respectively. The observed infrared luminosity L IR in the range 1−20 μm is derived for three objects; we obtain 2.0 × 10 3 L for IRS5A, 13 L for IRS5C, and 10 L for B273A. Conclusions. IRS5 might be a young quadruple system. Its primary star IRS5A is confirmed to be a high-mass protostellar object (∼9 M , ∼1 × 10 5 yrs); it might have terminated accretion due to the feedback from stellar activities (radiation pressure, outflow) and the expanding H ii region of M 17. The object UC1 might also have terminated accretion because of the expanding hypercompact H ii region, which it ionizes. The disk clearing process of the low-mass young stellar objects in this region might be accelerated by the expanding H ii region. The outflows driven by UC1 are running south-north with its northeastern side suppressed by the expanding ionization front of M 17; the blue-shifted outflow lobe of IRS5A is seen in two types of tracers along the same line of sight in the form of H 2 emission filament and mid-emission. The H 2 line ratios probe the properties of M 17 SW PDR, which is confirmed to have a clumpy structure with two temperature distributions: warm, dense molecular clumps with n H > 10 5 cm −3 and T ≈ 575 K and cooler atomic gas with n H ∼ 3.7 × 10 3 −1.5 × 10 4 cm −3 and T ∼ 50−200 K.

show abstract

“…Young massive star clusters (>10 4 M ) where we can find a coeval sample of massive stars at uniform metallicity are excellent laboratories to study massive stellar evolution, star formation process and abundance patterns in galaxies. Recently, several RSGCs (RSGC1, RSGC2, RSGC3, RSGC4, RSGC5, and Alicante 10) are found near Scutum-Crux arm in the Milky Way (Figer et al 2006;Davies et al 2007;Clark et al 2009;Negueruela et al 2010Negueruela et al , 2011Gonzalez-Fernandez & Negueruela 2012), and they are showing very interesting chemical abundance patterns regarding to the Galactic metallicity gradients. The high-resolution spectroscopic studies for the limited samples of RSGs in RSGC1, RSGC2, and RSGC3 (Davies et al 2009;Origlia et al 2016) report that the average metal abundances of the clusters are about subsolar, which is conflict with increasing metal abundance trend at lower R GC .…”

Section: Introductionmentioning

confidence: 99%

Chemical abundances of four red supergiants star clusters (RSGCs) in Scutum-Crux arm

Chun

2019

Proc. IAU

View full text Add to dashboard Cite

We investigate the spectral properties of red supergiant stars in the four RSGCs (RSGC2, RSGC3, RSGC4, RSGC5, and Alicante 10) in the Scutum-Crux arm of the Milky Way. The high-resolution (R: 45,000) near-infrared (H and K bands) spectra for 41 red supergiants were obtained using IGRINS at Gemini South telescope. The calibration of effective temperatures and gravities are derived based on the EWTi and EWCO using supergiants in IGIRNS library. The resulted temperatures and gravities are consistent with previous results. Model spectra were synthesized using derived stellar parameters from which we estimate metallicities and chemical abundances like α-elements. In our preliminary result, we find that overall four RSGCs indeed have sub-solar metallicities as already known in previous studies. The metallicity properties of RSGCs are far off the nominal metallicity trend in this region, and this suggests recent low-metallicity gas fueling into the inner disk and bulge.

show abstract

A third cluster of red supergiants in the vicinity of the massive cluster RSGC3

Cited by 33 publications

References 40 publications

CEN 34 – high-mass YSO in M 17 or background post-AGB star?

CEN 34 – high-mass YSO in M 17 or background post-AGB star?

VLT near- to mid-IR imaging and spectroscopy of the M 17 UC1 – IRS5 region

Chemical abundances of four red supergiants star clusters (RSGCs) in Scutum-Crux arm

Contact Info

Product

Resources

About