IGRINS Spectral Library

Park, Sunkyung; Lee, Jeong Eun; Kang, Wonseok; Lee, Sang-Gak; Chun, Moo-Young; Kim, Kang-Min; Yuk, In-Soo; Lee, Jae‐Joon; Mace, Gregory N.; Kim, Hwi; Kaplan, Kyle; Park, Chan; Oh, Jae Sok; Lee, Sungho; Jaffe, D. T.

doi:10.3847/1538-4365/aadd14

Cited by 39 publications

(43 citation statements)

References 70 publications

(81 reference statements)

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“…The spectroscopic calibration of IK Tau was done by dividing the observed spectrum of IK Tau with that of Rigel, because the true spectrum of Rigel is not expected to show any spectral features in the observed wavelength range at the spectral resolution of 12 000. 4 Available at http://www.jmmc.fr/data_processing_amber.htm We confirmed this by using the high-resolution (λ/∆λ ≈ 45 000) spectrum of HD 87737 (A0Ib) available in the IGRINS spectral library 5 (Park et al 2018). The star HD 87737 has the closest spectral type and luminosity class to Rigel in the IGRINS infrared stellar spectral library.…”

Section: Long-baseline Spectro-interferometric Observation With Vlti/mentioning

confidence: 62%

Exploring the innermost dust formation region of the oxygen-rich AGB star IK Tauri with VLT/SPHERE-ZIMPOL and VLTI/AMBER

Adam

Ohnaka

2019

A&A

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Context. Low-and intermediate-mass stars at the asymptotic giant branch (AGB) are known to be prevalent dust providers to galaxies, replenishing the surrounding medium with molecules and dust grains. However, the mechanisms responsible for the formation and acceleration of dust in the cool extended atmospheres of AGB stars are still open to debate. Aims. We present visible polarimetric imaging observations of the oxygen-rich AGB star IK Tau obtained with the high-resolution polarimetric imager VLT/SPHERE-ZIMPOL at post-maximum light (phase 0.27) as well as high-spectral resolution long-baseline interferometric observations with the AMBER instrument at the Very Large Telescope Interferometer (VLTI). We aim to spatially resolve the dust and molecule formation regions, and to investigate their physical and chemical properties within a few stellar radii of IK Tau. Methods. IK Tau was observed with VLT/SPHERE-ZIMPOL at three wavelengths in the pseudo-continuum (645, 748, and 820 nm), in the Hα line at 656.3 nm, and in the TiO band at 717 nm. The VLTI/AMBER observations were carried out in the wavelength region of the CO first overtone lines near 2.3 µm with a spectral resolution of 12 000. Results. The excellent polarimetric imaging capabilities of SPHERE-ZIMPOL have allowed us to spatially resolve clumpy dust clouds at 20-50 mas from the central star, which corresponds to 2-5 R when combined with a central star's angular diameter of 20.7±1.53 mas measured with VLTI/AMBER. The diffuse, asymmetric dust emission extends out to ∼73 R . We find that the TiO emission extends to 150 mas (15 R ). The AMBER data in the individual CO lines also suggest a molecular outer atmosphere extending to ∼1.5 R . The results of our 2-D Monte Carlo radiative transfer modelling of dust clumps suggest that the polarized intensity and degree of linear polarization can be reasonably explained by small-sized (0.1 µm) grains of Al 2 O 3 , MgSiO 3 , or Mg 2 SiO 4 in an optically thin shell (τ 550 nm =0.5±0.1) with an inner and outer boundary radius of 3.5 R and 25 R , respectively. The observed clumpy structures can be reproduced by a density enhancement of a factor of 3.0±0.5. However, the model still predicts the total intensity profiles to be too narrow compared to the observed data, which may be due to the TiO emission and/or grains other than homogeneous, filled spheres. Conclusions. IK Tau's mass-loss rate is 20 to 50 times higher than the previously studied AGB stars W Hya, R Dor, and o Cet. Nevertheless, our observations of IK Tau revealed that clumpy dust formation occurs close to the star as seen in those low mass-rate AGB stars.

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Section: Long-baseline Spectro-interferometric Observation With Vlti/mentioning

confidence: 62%

Exploring the innermost dust formation region of the oxygen-rich AGB star IK Tauri with VLT/SPHERE-ZIMPOL and VLTI/AMBER

Adam

Ohnaka

2019

A&A

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“…In IGRINS spectral library study (Park et al 2018), however, they find that EW co correlates with both log g and T ef f , while EW T i is the most sensitive indicator of T ef f . Thus, we adopt the method of Park et al (2018), and reaclibrate EW co and EW T i with template spectra of supergiants in IGRINS spectral library. The left panel of Figure 1 shows the effective temperatures as a function of calculated EW T i for the supergiants in IGRINS spectral library.…”

Section: Introductionmentioning

confidence: 94%

“…feature (EW co ) and spectral types (Davies et al 2007;Davies et al 2009;Negueruela et al 2010). In IGRINS spectral library study (Park et al 2018), however, they find that EW co correlates with both log g and T ef f , while EW T i is the most sensitive indicator of T ef f . Thus, we adopt the method of Park et al (2018), and reaclibrate EW co and EW T i with template spectra of supergiants in IGRINS spectral library.…”

Section: Introductionmentioning

confidence: 95%

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

Chun

2019

Proc. IAU

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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.

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“…More recently, a number of spectral libraries have been reported for wide varieties of stars (e.g., Ivanov et al 2004;Ranade et al 2004;Lodieu et al 2005;Hanson et al 2005;Venkata Raman & Anandarao 2008;Huynh et al 2011;Cooper et al 2013;Ghosh et al 2019). The spectral libraries of Lebzelter et al (2012) and Park et al (2018) stand out because of their significantly higher resolving power of R ∼ 100 000 and 45 000, respectively. However, they contain less stars and are not really suitable for galaxy population modeling.…”

Section: H Atmospheric Windowmentioning

confidence: 99%

The Infrared Telescope Facility (IRTF) spectral library

Morelli

Ivanov

Pizzella

et al. 2020

A&A

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Context. Stellar population studies in the infrared (IR) wavelength range have two main advantages with respect to the optical regime: they probe different populations, because most of the light in the IR comes from redder and generally older stars, and they allow us to see through dust because IR light is less affected by extinction. Unfortunately, IR modeling work was halted by the lack of adequate stellar libraries, but this has changed in the recent years. Aims. Our project investigates the sensitivity of various spectral features in the 1−5 μm wavelength range to the physical properties of stars (Teff, [Fe/H], log g) and aims to objectively define spectral indices that can characterize the age and metallicity of unresolved stellar populations. Methods. We implemented a method that uses derivatives of the indices as functions of Teff, [Fe/H] or log g across the entire available wavelength range to reveal the most sensitive indices to these parameters and the ranges in which these indices work. Results. Here, we complement the previous work in the I and K bands, reporting a new system of 14, 12, 22, and 12 indices for Y, J, H, and L atmospheric windows, respectively, and describe their behavior. We list the equivalent widths of these indices for the Infrared Telescope Facility (IRTF) spectral library stars. Conclusions. Our analysis indicates that features sensitive to the effective temperature are present and measurable in all the investigated atmospheric windows at the spectral resolution and in the metallicity range of the IRTF library for a signal-to-noise ratio greater than 20−30. The surface gravity is more challenging and only indices in the H and J windows are best suited for this. The metallicity range of the stars with available spectra is too narrow to search for suitable diagnostics. For the spectra of unresolved galaxies, the defined indices are valuable tools in tracing the properties of the stars in the IR-dominant stellar populations.

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IGRINS Spectral Library

Cited by 39 publications

References 70 publications

Exploring the innermost dust formation region of the oxygen-rich AGB star IK Tauri with VLT/SPHERE-ZIMPOL and VLTI/AMBER

Exploring the innermost dust formation region of the oxygen-rich AGB star IK Tauri with VLT/SPHERE-ZIMPOL and VLTI/AMBER

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

The Infrared Telescope Facility (IRTF) spectral library

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