• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Searching for Multiple Populations in Star Clusters Using the China Space Station Telescope

    2022-10-25 08:24:44ChengyuanLi李程遠(yuǎn)ZhenyaZheng鄭振亞XiaodongLi李霄棟XiaoyingPang龐曉瑩BaitianTang湯柏添AntoninoMiloneYueWang王悅HaifengWang王海峰andDengkaiJiang姜登凱
    關(guān)鍵詞:王悅海峰

    Chengyuan Li (李程遠(yuǎn)), Zhenya Zheng (鄭振亞), Xiaodong Li (李霄棟), Xiaoying Pang (龐曉瑩), Baitian Tang(湯柏添), Antonino P. Milone, Yue Wang (王悅), Haifeng Wang (王海峰), and Dengkai Jiang (姜登凱)

    1 School of Physics and Astronomy, Sun Yat-sen University, Daxue Road, Zhuhai, Guangdong 519082, China; lichengy5@mail.sysu.edu.cn

    2 CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area, Zhuhai 519082, China

    3 CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030, China

    4 Division of Optical Astronomical Technologies, Shanghai Astronomical Observatory, Shanghai 200030, China

    5 Department of Physics, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China

    6 Shanghai Key Laboratory for Astrophysics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China

    7 Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Vicolo dell’Osservatorio 3, I-35122, Padua, Italy

    8 Istituto Nazionale di Astrofisica—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, IT-35122, Padua, Italy

    9 Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China

    10 GEPI, Observatoire de Paris, Université PSL, CNRS, Place Jules Janssen F-92195, Meudon, France

    11 Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming 650216, China

    12 Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650216, China

    13 Center for Astronomical Mega-Science, Chinese Academy of Sciences, Beijing 100101, China

    Abstract Multiple stellar populations (MPs) in most star clusters older than 2 Gyr, as seen by lots of spectroscopic and photometric studies,have led to a significant challenge to the traditional view of star formation.In this field,spacebased instruments, in particular the Hubble Space Telescope (HST), have made a breakthrough as they significantly improved the efficiency of detecting MPs in crowded stellar fields by images. The China Space Station Telescope(CSST)and the HST are sensitive to a similar wavelength interval,but the CSST covers a field of view which is about 5–8 times wider than that of HST.One of its instruments,the Multi-Channel Imager(MCI),will have multiple filters covering a wide wavelength range from NUV to NIR, making the CSST a potentially powerful tool for studying MPs in clusters. In this work, we evaluate the efficiency of the designed filters for the MCI/CSST in revealing MPs in different color–magnitude diagrams (CMDs). We find that CMDs made with MCI/CSST photometry in appropriate UV filters are powerful tools to disentangle stellar populations with different abundances of He, C, N, O and Mg. On the contrary, the traditional CMDs are blind to multiple populations in globular clusters(GCs).We show that CSST has the potential of being the spearhead instrument for investigating MPs in GCs in the next decades.

    Key words: (Galaxy:) globular clusters: general – stars: abundances – techniques: photometric

    1. Introduction

    Several decades ago,star clusters were thought of as simplestellar populations (SSPs), i.e., a sample of stars with different masses that are identical in age and metallicity. The traditional star formation picture concludes that all stars formed in clustered environments should inherit the same chemical composition of their parental molecular cloud, and thus are chemically homogeneous, and are coeval because the strong initial stellar feedback makes the star formation mode a burst(e.g.,Calura et al.2015).This view has been discarded because of the detection of star-to-star chemical variations in almost all globular clusters(GCs)(see the review of Gratton et al.2019),known as multiple stellar populations (MPs) .

    Significant chemical variations in star clusters can be detected among many light elements. Some of the most common elements include He,C,N,O,Na,Mg and Al.Extensive studies have shown that GCs contain more than one stellar population at different evolutionary stages:main sequence(MS,Piotto et al.2007;Milone et al. 2019), red-giant branch (RGB, Carretta et al. 2003;Mucciarelli et al. 2015; Milone et al. 2017; Latour et al. 2019;Milone et al. 2020a), horizontal branch (HB, Gratton et al. 2011)and asymptotic giant branch(AGB,Wang et al.2016;Marino et al.2017).The MP phenomenon is likely a global feature for stars at different stages, starting from the MS to evolved giants (e.g., 47 Tuc, NGC 1851, Milone et al. 2012; Cummings et al. 2014;Gruyters et al. 2017; Yong et al. 2015). In this article, we do not discuss iron-complex clusters (Type II GCs, e.g., Marino et al.2015,2019,2021).These clusters comprise the most massive GCs in the Galaxy (e.g., ω Cen, Johnson & Pilachowski 2010). Their origins may differ from most mono-metallic GCs,such as a tidally disrupted dwarf galaxy.

    The elemental abundance variations are correlated with each other. Observations show that for clusters with MPs, the total abundance of C, N and O usually remains unchanged, δ[(C+N+O)/Fe]~0 (Cohen & Meléndez 2005; Marino et al.2016). Since most GCs have constant overall CNO abundance,an increase in nitrogen corresponds to depletion in carbon and oxygen. Moreover, in many metal-poor GCs with MPs,sodium anti-correlates with oxygen (e.g., Carretta et al. 2006, 2009a,2009b). The abundances of magnesium and aluminum are anticorrelated as well,but this pattern disappears in metal-rich GCs(or is very weak, Pancino et al. 2017).

    The MP phenomenon is very common in old GCs, and it exhibits links to global parameters. A lot of comprehensive analyses have shown that the cluster’s total mass is a key parameter which controls some properties of MPs (e.g., the fraction of second generation stars and the internal helium and nitrogen variations, Milone et al. 2017, 2018). Indeed, many scenarios proposed to account for the origin of MPs strongly indicate the importance of cluster total masses. In these scenarios, the polluters include intermediate-age AGB stars(D’Ercole et al. 2010), fast-rotating massive dwarfs (Decressin et al. 2007), massive interacting binaries (de Mink et al. 2009)and single supermassive MS stars (Denissenkov & Hartwick 2014).Studies of clusters in the Magellanic clouds indicate that some clusters older than ~2 Gyr have a hint of MPs, while their younger counterparts do not (Martocchia et al. 2018;Milone et al. 2020a). This has led to a hypothesis that cluster age determines the occurrence of MPs, perhaps linked to some non-standard stellar evolutionary processes (Bastian &Lardo 2018,however,see Li et al.2020;Li 2021).However,so far only a few young massive clusters (YMCs) (younger than~6 Gyr) have been scrutinized in terms of their stellar populations (Gratton et al. 2019, their Figure 7). It remains unclear if the phenomenon of MPs is a common pattern for YMCs, which may represent the infant stage of GCs we see today.

    Both spectroscopic and photometric studies provide complementary information for understanding the MPs. Spectroscopic studies have provided many details about the chemical properties of stellar populations. Mostly, this method is sensitive to the brightest stars. Ultraviolet (UV)-optical-based photometry is a high efficiency method that overcomes the effect of crowding of clusters, allowing us to examine millions of stars at different evolutionary stages and positions,even in the densest regions of clusters.This is important because to fully understand the origin of MPs, a large sample of clusters covering an extensive parameter space is required.An example of photometric studies of MPs is the breakthrough made by the Hubble Space Telescope(HST).The high spatial resolution of the HST allows deep observations into clusters’ core region, resulting in clean color–magnitude diagrams (CMDs) with subtle features. Actually, the effect of the He variation in GCs is detected through photometry rather than spectroscopy (see Piotto et al. 2007;Bellini et al. 2010 for early helium determination in ω Cen and NGC 2808 respectively)because the helium line associated with photospheric transitions can be detected only in stars hotter than 8,500 K. Moreover, the abundances inferred from HB stars hotter than ~11,500 K are not representative of the stellar helium content. As a consequence, helium abundance can be only estimated in HB stars that span a small temperature interval14The He II 10 830 ? absorption line can be used for He abundance determination, but it requires expensive high-resolution spectra in the infrared passband.(e.g., Marino et al. 2014).

    Because He enrichment will reduce the stellar atmospheric opacity and increase the interior mean molecular weight,stars with different He abundances will have different surface temperatures and nuclear burning rates in each stage, thus complicating the CMD(e.g.,Piotto et al.2007;Milone 2015).For other light elements, such as C, N and O, their variations can be seen in filters encompassing wavelengths shorter than~4000 ? in late-type stars. Late-type stars with the same global parameters(Teff,logg,[Fe/H]),but which are different in CNO abundances, will have their spectral energy distribution (SED) almost identical in optical passband but different in the UV (e.g., Milone et al. 2015a, 2015b). Because most CNO-related features are distributed in the wavelength range of UV to blue:for example,most O-absorptions dominate the range of λ ≤3000 ?, the NH-, CN- and CH-absorptions are centered at λ=3370 ?, 3883 ? and 4300 ?, respectively. In addition,the Mg II doublet centered at 2795/2805 ? is one of the most important UV-absorption features, which can be detected by corresponding UV-passbands (e.g., Milone et al.2020b). We recommend Milone (2020) as a nice summary.Indeed, as affirmed by the HST UV Legacy Survey of Galactic Globular Clusters, almost all Galactic GCs contain MPs (Piotto et al. 2015; Milone et al. 2017), undoubtedly indicating that UV-optical telescopes are powerful tools for studying MPs.

    The China Space Station Telescope (CSST) is a two-meter UV-optical space telescope, co-orbiting with the China Manned Space Station, which will be launched around~2024. The Multi-Channel Imager (MCI), a three-channel simultaneous imaging covering a wavelength range of 0.255–1 μm,is one of the five instruments on board the CSST.The MCI has a spatial resolution similar to the HST(0 18 at 633 nm).Its field of view (FoV) is 7 5×7 5, about 500% of the ACS/WFC@HST (202″×202″) and 770% of the UVIS/WFC3@HST (162″×162″), which thus covers larger fields of star clusters than the HST.It will be equipped with a 9k×9k CCD,and 30 filters with different bandwidths (10 per channel).Overall, CSST is an HST-like next generation space telescope with similar wavelength coverage and spatial resolution and a larger FoV.For details about the CSST,we refer to the review of Zhan (2021).

    Table 1 MCI/CSST Filter Parameters (Ranked by Increasing Mean Wavelength)

    It is, therefore, essential to study the effect of MPs in the MCI/CSST photometric system. This work aims to find the most suitable filters which can maximize the color separation between MPs in CMDs. The article is organized as follows: in Section 2,we introduce the details of our method.We show our main results in Section 3. A brief discussion of our results is presented in Section 4.

    2. Bolometric Corrections for Multiple Stellar Populations

    The current designation of the MCI/CSST photometric system includes 15 wide passbands (full width at half maximum (FWHM)/λc>15%, where λcis the mean wavelength of the passband), 3 medium passbands (5%<FWHM/λc<10%) and 12 narrow passbands (FWHM/λc<3%, except for the CSST-f343n filter, which follows the definition of the HST/WFC3-F343N). There are two dichroic filters in the light path of MCI, which divide the wavelength range of MCI into three channels at 255 nm–430 nm,430 nm–700 nm, and 700 nm–1000 nm. These dichroic filters prevent the use of filters such as g and i bands. In Table 1 we summarize some basic information on the adopted filters,including (1) their mean wavelengths, λc; (2) the FWHM; (3)the corresponding wavelengths of 50% of the maximum transmission curve(left:λL50,right:λR50);(4)the steepness of the transmission curve, described by Tanx=Δλx/λx, where x is L50/R50 and Δλxis the wavelength difference between 0%and 100% maximum transmission, and (5) the average transmission efficiency within FWHM, T50. The transmission curves for MCI/CSST filters are presented in Figure 1 (wide passbands) and Figure 2 (narrow and medium passbands). We do not show the transmission curve for the CSST-WU passband because it is being redesigned.

    Figure 1. The total transmission curves for MCI/CSST wide filter bands, with detector quantum efficiency being considered.

    Figure 2. Same as Figure 1, for narrow and medium (dashed curves) filters of the MCI/CSST.

    To evaluate the effect of MPs on the MCI/CSST photometric system,we need to select a given chemical pattern to simulate its effect on photometry.In this work,we studied two cases,an NGC 2808-like MP and a less extreme case with chemical variations half those of NGC 2808.We study these two cases because NGC 2808 represents a quintessential (extreme) example of a mono-metallic GC that exhibits variations in almost all light elements(Piotto et al.2007; Gratton et al. 2011; Mucciarelli et al. 2015; Wang et al.2016; Latour et al. 2019). The half-NGC 2808 chemical pattern can represent many less massive GCs with MPs(see,Milone et al.2018). We utilized the Dartmouth Stellar Evolution Database(Dartmouth model) to generate isochrones with different He abundances(Dotter et al.2008).We define two stellar populations described by two isochrones to represent an NGC 2808-like MP.The Dartmouth model allows us to interpolate any isochrone with parameters within -2.5 <[Fe/H]<+0.5 dex, initial He abundances from Y=0.245 to 0.40,and ages from 1 Gyr to 15 Gyr.It is a suitable stellar model to describe an NGC 2808-like GC with an extreme helium enrichment. Based on the literature of Piotto et al. (2007), we adopt the age and metallicity of our two populations,both t=12 Gyr and[Fe/H]=-1.0 dex,respectively.They are different in He abundance, with Y=0.25 for one population and Y=0.40 for the other (hereafter 1P and 2P). The[α/Fe] is 0.0 dex as we confirm that it has a negligible effect on the derived isochrones.

    The derived isochrones contain a series of physical parameters, including stellar masses (M/M⊙),effective surface temperatures (logTeff), surface gravity (logg) and luminosities(l ogL L⊙). These parameters, along with the adopted metallicity ([Fe/H]), are used for calculating the bolometric corrections through the PARSEC database of bolometric correction(The YBC database, Chen et al. 2019). The YBC database provides absolute magnitudes in the CSST filter set(we obtain the specific MCI/CSST magnitudes through private communication with Dr. Chen Yang).

    We relied on the package SPECTRUM (version 2.77) to calculate isochrones with specific elemental abundances,and thus loci for stellar populations.Given a stellar atmosphere model and certain inputs, SPECTRUM calculates a synthetic stellar spectrum with input parameters.SPECTRUM can calculate reliable synthetic B- to mid-M-type stellar spectra. The synthetic spectra are calculated under the silent&isotope& ATLAS modes.The input line lists are obtained from the main page of the SPECTRUM package,15http://www.appstate.edu/~grayro/spectrum/ftp/download.htmlwhich includes more than 1.6×108absorption lines covering a wavelength range of 900 ?–40000 ?. The input atmosphere models were computed with the ATLAS9 model atmosphere program written by Kurucz(1993)16https://wwwuser.oats.inaf.it/castelli/grids.htmlwith parameters([Fe/H], logg, Teff) from the base isochrone.

    We calculate synthetic spectra with different elemental abundances for 1P and 2P stars. Under the adoption of [Fe/H]=-1.0 dex and assuming that the total abundance of CNO remains unchanged, we set all 2P stars to have δ[N/Fe]=+1.0 dex, and δ[O/Fe]=δ[C/Fe]=-0.5 dex. Spectroscopic studies show that NGC 2808 has an Na–O anti-correlation for its member stars (Carretta et al. 2009a). We adopt δ[Na/Fe]=+0.5 dex through visual inspection(Figure 7 of Carretta et al. 2009a), corresponding to a 0.5 dex depletion of the O abundance.According to Pancino et al.(2017),NGC 2808 also exhibits Mg–Al anti-correlation, and we set a δ[Mg/Fe]=-0.5 dex and δ[Al/Fe]=+1.0 dex for 2P stars in our model. We will examine the effects of an NGC 2808-like MP both with/without Y variation (hereafter Case 1 and Case 2 respectively), and a less extreme case with all element variations being half that of NGC 2808 (no Y variation, Case 3). We also test other effects of individual element variation,including(1)the Y variation,(2)the CNO variation,(3)the Na variation,(4)the Mg variation and(5)the Al variation,as well.In these cases, we (not-so-)arbitrarily assume reasonable variations based on literatures (Piotto et al. 2007; Carretta et al.2009a;Pancino et al.2017).We summarize these adopted models in Table 2. The isochrones for chemically enriched stellar populations, and thus 2P loci, are calculated as follows,

    where Miis the expected absolute magnitude for a chemically enriched star observed through the filter band i (see Table 1),and Mi,0is the corresponding absolute magnitude for the counterpart with normal chemical abundance. fλandλf0are their radiative fluxes (at 10 pc) we received at the central wavelength of λ,which are calculated through SPECTRUM.Sλ,iis the transmission curve of a specific filter band i. The quantities λ1and λ2indicate the lower and upper wavelength limits respectively. According to the wavelength range of the CSST, we set them as 2500 ? and 10,000 ?, respectively.

    Finally,we will compare the loci of the 1P(described by the standard isochrone) with that of the 2P. To quantify their performances at separating two populations, we will calculate their color differences referring to the filter CSST-f814w,Mi-Mf814w,for a referenced RGB star(below the RGB bump)with Mf555w=2.0 mag and a bottom MS star with Mf555w=8.0 mag. The selection of these two stages is arbitrary, which corresponds to a K1-type giant and a K4-type dwarf. We confirm that they are sufficiently cool to exhibit prominent absorption features of CNO-related molecules. In this work, a positive color difference means the chemically enriched population of stars (defined in Table 2) is bluer than normal stars.

    Figure 3.The effect of helium variation in the CMD.Left panel:the CMD in Mf555w-Mf814w vs.Mf555w for 1P(black solid line)and 2P(He-rich,red dashed line).Grey dotted lines signify the RGB and MS stages at Mf555w=2.0 and 8.0 mag.The same loci for 1P and 2P under the UVIS/WFC3 HST photometric system are also present(gray solid and dashed lines).Two example RGB stars are highlighted by black(He-normal)and red(He-rich)circles.They are at the same stage indicated by the DSEP model.The upper-right panel exhibits their synthesis spectra(black:helium-normal;red:helium-rich).The bottom-right panel features the spectrum of their magnitude difference.

    Table 2 Adopted Models with Different Abundance Variations for 2P Stars

    3. Color–Magnitude Diagrams

    In this section we present our main results, which include CMDs of 1P and 2P loci with different chemical patterns(Table 2).

    3.1. Helium Variation

    Helium is the direct product of H-burning. Polluted stars with chemical anomalies must be He-enriched. As introduced,member stars of GCs are too cold to produce He absorptions at UV-optical passbands.For old stellar populations like GCs,the effect of He enrichment is evolutionary.The effect of helium is reflected by the value of the average molecular weight, μ, and the opacity, κ0. Because the helium opacity is lower than the hydrogen opacity, an increase of the helium abundance at constant metallicity will increase μ and decrease κ0,making the stellar evolutionary track have higher luminosity (L) and effective temperature (Teff). In addition, the increased L will make stars burn their central hydrogen faster than He-normal stars. As a result, the He-enriched population will always exhibit a lower main-sequence turnoff (MSTO) because it evolves more rapidly than its coeval He-normal stellar population.

    In Figure 3 we display the isochrones for the 1P(He-normal,Y=0.25)and 2P(Y=0.40)stars(left panel).In the upper-right panel we show two giant spectra with different He abundances at the same evolutionary stages,as indicated by the black(Henormal) and red (He-rich) circles in the left panel. In the

    Table 3 Color Differences of Mi-Mf814w(i Indicates Different Filter Bands,see Table 1)between 1P and 2P(for Different Chemical Variations[var.],see Table 2),for the Referenced RGB Stage

    Note. The number associated with an asterisk means this color difference can be resolved at the distance of NGC 2808 with a total exposure time of 300 s (see discussions in Section 4).bottom-right panel we exhibit their flux ratios in terms of- 2.5 logf2f1(f2and f1are fluxes of 2P and 1P stars respectively), which is the same as a magnitude difference spectrum. Figure 3 demonstrates that for two stars at the same evolutionary stage, the He-rich star is brighter/bluer than the normal star. The color axis in Figure 3 is described by Mf555w-Mf814w, and for the referenced RGB(MS) stage(indicated by gray dotted lines), the color difference between the two populations is Δ(Mf555w-Mf814w)~0.07(0.15) mag,respectively. As a comparison, we also show the same loci for 1P and 2P under the HST photometric system (UVIS/WFC3),as indicated by gray solid(1P)and dashed(2P)lines in the left panel.We find that the color separations between 1P and 2P are similar in the MCI/CSST and UVIS/WFC3 HST filter systems. The color differences between other passbands,Δ(Mi-Mf814w), are calculated, which are presented in Tables 3 and 4 (for the RGB and MS stages respectively).

    Figure 3 affirms that helium-rich MS and RGB stars are hotter than their normal counterparts. A wide color baseline is efficient for disentangling stellar populations with different helium abundances. In Figure 4 we show three isochrone pairs which describe Y=0.25 and Y=0.40 populations in different colors,Mf275w-Mf814w, Mf336w-Mf814wand Mf555w-Mf814w(from left to right respectively).It shows that a wider color baseline can resolve a larger color difference between the two populations.These color differences between 1P and 2P are similar to those under the UVIS/WFC3 HST photometric system(gray solid and dashed lines,respectively).Figure 5 presents the color differences in different filter bands, Mi-Mf814w. Indeed, we find that the bluer the first filter band,the higher the color difference between the two populations. The maximum color differences at both the RGB and MS stages appear in Mf275w-Mf814w, which are Δ(Mf275w-Mf814w)~0.4 mag and ~0.7 mag, respectively. To resolve such color differences, a minimal signal-to-noise ratio ofSNR ~4 for each passband is required (see discussions in Section 4).

    Table 4 The Same as Table 3, Except that the Reference Stage is the Bottom MS

    3.2. Carbon, Nitrogen and Oxygen Variations

    Measuring CNO variations in photometry requires specific filter bands. As introduced in Section 1, filters centered at the wavelength of λ ~3370 ? (i.e., CSST-f336w, CSST-f343n)would see N-rich stars fainter than normal stars (at the same stage). Since N-enriched stars are CO-depleted, these stars should be brighter than CO-normal stars in filters covering the wavelength range of λ <3000 ? (OH-absorption dominated)or λ ~4300 ?(CH-absorption).Unfortunately,the latter is not included in the MCI/CSST filter system. We present the color differences between the normal population and the population with CNO anomalies (see Table 2) in different color baselines in Figure 6.Indeed,we find that around ~3370 ? normal stars are brighter than N-rich stars. They present negative color differences in color bands involving specific filters (in particular the CSST-f336w and CSST-f343n filters). For filters bluer than ~3000 ? (CSST-NUV, CSST-f280n,CSST-f275w), normal stars are fainter than N-rich stars as the latter are O-depleted, and their color differences are positive.

    Figure 6 indicates that if we select a color band involving a filter with λc<3000 ? (CSST-f275w) and a filter with λc~3370 ? (CSST-f343n), we can maximize the color difference between the normal and N-rich population of stars.It also tells us that the color separation is more significant at the MS stage than the RGB, because the selected MS stage has a surface temperature lower than that of the RGB. Stars with lower atmosphere temperatures will have stronger CNO-related molecular absorptions. In Figure 7 we present two CMDs for the normal and N-enriched (CO-depleted) populations (1P and 2P respectively). The upper-left panel presents the CMD involving two visible filter bands, CSST-f555w and CSSTf814w, which show a negligible difference between the two populations. The bottom-left panel features two populations in the color of Mf275w-Mf343n, which exhibit a dramatic color difference. Indeed, similar filter bands are frequently used in HST photometry for studying MPs of GCs (e.g.,Milone et al.2018;Nardiello et al.2018).We present these loci under the same UVIS/WFC3 HST filters in the panel. Again,the color differences between the 1P and 2P revealed by CSST and HST are similar.In the right panels of Figure 7,we display spectra of the referenced RGB star and its counterpart with CNO anomalies (upper) and their magnitude difference spectrum (lower), which explains why the combination of CSST-f275w and CSST-f343n can maximize their color difference. The color differences caused by CNO variation in different filter bands are present in Tables 3 and 4.

    Figure 4.From left to right,loci of normal (1P,black solid lines)and heliumrich (2P, black dashed line) populations in colors of Mf275w-Mf814w,Mf336w-Mf814w and Mf555w-Mf814w, respectively. The same loci for 1P and 2P under the UVIS/WFC3 HST photometric system are indicated by gray solid and dashed lines respectively.

    3.3. Sodium Variation

    We apply the same analysis to stellar populations with different Na abundance. Although for MPs the Na and O abundances are always anti-correlated, in this subsection we only consider an Na enrichment of δ[Na/Fe]=0.5 dex. More realistic considerations (NGC 2808-like) will be discussed later.Our analysis shows that Na enrichment has a very limited effect on photometry. Although lots of Na I and Na II absorption lines occur in the UV band, the maximum color difference between the two populations does not exceed 0.03 mag. We also find that Na-enrichment has opposite effects on the MS and RGB stages. Na-rich stars are slightly bluer than normal stars at the RGB stage,but are redder at the bottom MS,as depicted in Figure 8. We conclude that the filters designed for MCI/CSST are not suitable to identify MPs with different Na abundance.

    3.4. Magnesium Variation

    The most significant difference between the normal and Mgrich population stars appears in the color band of Mf280n-Mf814w. Our analysis shows that for the RGB stage,their color difference reaches Δ(Mf280n-Mf814w)=-0.4 dex.This is caused by the combination of the Mg II 2795 ? and 2803 ? absorption lines. Intriguingly enough, the color difference is reversed for the bottom MS populations. The Mg-rich population is bluer than the normal population in most color bands involving UV filters, but is redder in Mf502n-Mf814w. Since its chemical abundances are identical to the RGB, this difference is possibly caused by their surface gravity (logg) difference. Since the degree of ionization depends on the stellar surface gravity, it mainly affects the wavelength range below 3650 ?.Indeed,as shown in Figure 9,filters with central wavelength below 4000 ? are significantly affected. The lower surface temperature may also affect the SED: for very late stars, the enhanced Mg abundance will produce a deeper absorption band, including Mg I 5167 ?,5173 ? and 5184 ?,than a normal star, which thus affects the CSST-f502n photometry. Since to explain the details of this difference is beyond the scope of this article, we leave it as an open question for future investigation.

    Figure 9 indicates that the separation between normal and Mg-rich is most significant in the color band of Mf280n-Mf502n.We present the CMDs of normal(1P)and Mg-rich(2P)populations in the left panels of Figure 10.We find the optimal filter sets used for separating the normal and Mg-rich populations are CSST-f280n and CSST-f502n (for HST,these are F280N and F502N accordingly). In these two filters,the color difference between 1P and 2P is much more significant than that observed in optical passbands (i.e.,Mf555w-Mf814w). The color difference seen by the CSST is less significant than that observed by HST at MS, however.Because the transmission curve of the HST F280N filter is higher than that of CSST,the former is more sensitive to small Mg variation. In the right panels of Figure 10 we present the magnitude difference spectra between the Mg-rich and normal reference stars(top-right:RGB stars;bottom-right: bottom MS stars).

    3.5. Aluminum Variation

    Figure 5. Color differences between normal and helium-enhanced populations in different color bands.

    Figure 6. Same as Figure 5, but for normal and N-enriched (CO-depleted) populations.

    The effect of Al-enrichment is similar to that of Mg(Figure 11). When considering the colors of Mi-Mf814w,where Mionly contains filter bands bluer than 3800 ?, the Alrich population is redder than the normal population at RGB stage, but is bluer at the bottom MS range. These color differences are very small (|Δ(Mi-Mf814w)|<0.02 mag).Only for the bottom MS range in the color band of Mf395n-Mf814w, the Mg-rich population is redder than the normal population with Δ(Mi-Mf814w)<-0.05 mag. This is caused by the combination of Al I lines at 3944 ? and 3962 ?.However,resolving such a small color difference at the bottom MS in a narrow filter band may require a very long exposure time (see Section 4). We, therefore, do not recommend using the CSST photometry to study Al variations in star clusters.

    3.6. NGC 2808-like Multiple Populations

    Above we only discuss the effects of MPs with variations of a few or individual elements. A more realistic case should involve variations in all these elements. In this work, we only consider the variations of He,C,N,O,Na,Mg and Al because they are the most abundant elements in stellar atmospheres,producing strong absorption features.For GCs with MPs,Li,F,and some s-process elements may vary from star-to-star as well. Because of their small mass fraction, strong photometric effects caused by these variations are not expected. In this section, we study two cases that follow the definitions inpopulations. We also suggest an alternative color band of MNUV-Mu.Although the color difference between the 1P and 2P is not so significant in this band like Mf275w-Mf343n, the CSST-NUV and CSST-u filters have much wider FWHM than the CSST-f343n (see Figures 1 and 2), which can save lots of exposure time.In addition,these two filter bands will be used in the CSST main survey as well (Gong et al. 2019). In Figure 13 we show the CMDs of two populations in CMDs involving colors of Mf275w-Mf343n, MNUV-Muand Mf555w-Mf814w. The isochrones described by F275W and F343N passbands of UVIS/WFC3 HST are represented by gray solid and dashed lines, respectively. The CSST and HST can separate well the loci for 1P and 2P, and their separations are similar.

    Figure 7. Same as Figure 1, but for normal and N-enriched (CO-depleted) populations (1P and 2P respectively). In left panels we exhibit two loci under colors of Mf555w-Mf814w(top)and Mf275w-Mf343n(bottom),respectively.Grey solid and dashed lines are loci of 1P and 2P in UVIS/WFC3 HST filters respectively.Spectra in right panels are for RGB reference stars.

    The color differences between 1P and 2P stars for Case 2 are presented in Figure 14. Driven by the He-enrichment, 2P becomes bluer in all color bands. For this case, the color difference between the 1P and 2P bottom MS can reach Δ(Mf275w-Mf814w)>0.8 mag. Although He variation produces the most significant color difference,we can derive other element variations through different color bands. For example,in Figure 5 we can see if the 1P and 2P are only different in He abundance, they will show a color difference of Δ(M343n-Mf814w)~0.2–0.5 mag. This difference becomes negligible if they are also different in CNO abundances, because N-enrichment (CO-depletion) will make the 2P stars redder than normal stars,compensating the effect of He-enrichment.In addition, if the He-rich population is Mg-depleted, it will become much bluer in the Mf280n-Mf814wcolor band(Δ(Mf280n-Mf814w)~0.6–0.8 mag) than the case without Mg-depletion (Δ(Mf280n-Mf814w)~0.2–0.4 mag, Figure 5).This situation is illustrated in Figure 15.

    3.7. A Less Extreme Case

    Figure 8. Same as Figure 5, but for normal and Na-enriched populations.

    Figure 9. Same as Figure 5, but for normal and Mg-enriched populations.

    We have calculated a less extreme model of MPs.According to Milone et al. (2018), most less massive GCs (?105M⊙) do not exhibit a significant helium spread (δY ~0.00–0.02, their Figure 13), but these clusters still manifest light element variations (their Table 3). Most GCs have N, Mg, and Al variations that are about half those of NGC 2808. In this case,we set an N-enrichment for 2P stars of Δ[N/Fe]=0.7 dex,and these 2P stars are depleted by Δ[C/Fe]=Δ[O/Fe]=-0.18 dex, to make the total CNO abundance constant. Their Mgdepletion is Δ[Mg/Fe]=-0.2 dex, with an Al-enrichment of Δ[Al/Fe]=+0.7 dex,as determined through visual inspection from Pancino et al. (2017). The Na-enrichment is Δ[Na/Fe]=+0.2 dex. In this case, the N-enrichment and Mgdepletion for 2P stars are half of those in NGC 2808.Using the same method,we have calculated the color differences between 1P and 2P for RGB and MS stars, which are presented in Figure 16.We find that under this case,the color differences of Mi-Mf814w(Miis the magnitude under any selected filter)are less obvious than in Case 1,as expected,but they still produce significant color differences when involving UV filter bands.The Mf343nis the most important filter band for separating 1P and 2P, which describes the depth of the NH-absorption feature. Mf275w, Mf280nand MNUVcan maximize the color difference as they measure the O-depletion.The color band like Mf343n-Mf275wis more sensitive than traditional optical colors(e.g., V-I).

    In summary, multi-band photometry of the MCI/CSST involving these key filters is crucial for determining detailed abundance variations between different stellar populations.

    4. Discussion

    Figure 10.Same as Figure 7,but for normal and Mg-rich populations.In right panels we present the magnitude difference spectra between normal and Mg-rich RGB(top) and MS (bottom) stars (f2 and f1 are fluxes of 2P and 1P stars respectively).

    Figure 11. Same as Figure 5, but for normal and Al-rich populations.

    In this work we study the photometric patterns of MP chemical variations on synthetic magnitudes of the MCI/CSST filter system. We studied five cases, including He variation,CO-depletion and N-enrichment,Na-enrichment,Mg-depletion and Al-enrichment, two cases with different chemical patterns similar to the GC NGC 2808(with/without He variation), and one less extreme case which better represents many other GCs.We find that colors involving various UV filters are well suited to separating MPs with different He, C, N, O and Mg abundances, but are not suitable for Na and Al variations. We find that the filter CSST-f343n is essential for deriving CNO variations. The color band involving the CSST-f280n filter is optimal for separating MPs with different Mg abundance. The performances of these filters are similar to their counterparts in the UVIS/WFC3 HST photometric system. Considering the exposure time requirement, we suggest that wide filter bands such as CSST-f275w, CSST-NUV and CSST-u can be used for studying MPs in star clusters.

    Figure 12. Same as Figure 5, in this figure, the 2P have variations in the C, N, O, Na, Mg and Al elements, as defined in Table 2 (Case 1).

    Figure 13.Loci of 1P and 2P(Case 1)in different color bands(black:Mf555w-Mf814w;blue:MNUV-Mu;red:Mf275w-Mf343n;gray:MF275W-MF343N,for HST).The solid and dashed lines represent 1P and 2P stars respectively.

    Although currently simulated artificial images for MCI/CSST observations are not available, it is useful to have a preliminary evaluation of whether one can disentangle MPs with MCI/CSST at a typical distance of GCs.We make use of the online CSST exposure time calculator(ETC)for the MCI,17http://etc.csst-sc.cn/ETC-nao/etc.jspto study if we can resolve the referenced RGB and bottom MS stars at the distance of NGC 2808 ((m-M)0~15.6 mag,Kunder et al. 2013) in given color bands. For two RGB stars(mf555w=Mf555w+15.6=17.6 mag), we adopt one exposure,with a total exposure time of ~300 s,while for the bottom MS stars(mf555w=Mf555w+15.6=23.6 mag),we set a total of 18 exposures with an exposure time of 300×180=54,000 s(With this exposure time, the SNR for CSST-f814w at the bottom MS is roughly the same as the SNR at the RGB phase with 300 s exposure time.). For a selected filter, the ETC will return its SNR under a given exposure time. If the resulting SNR is four times the minimum requirement for disentangling MPs, we identify the filter as suitable (marked by asterisks in Tables 3 and 4). We find that using MCI/CSST to resolve NGC 2808-like MPs at the bottom MS is feasible through specific color bands (i.e., MNUV-Mf814w).

    Figure 14. Same as Figure 5, but in this figure, the 2P have variations in the He, C, N, O, Na, Mg and Al elements, as defined in Table 2 (Case 2).

    Figure 15.CMDs of 1P(black solid line),2P(Case 2,red dashed line)and He-rich population(without other element variations,black dashed line),in the color bands of Mf343n-Mf814w (left) and Mf280n-Mf814w (right).

    Figure 16.Same as Figure 5,but for a less extreme case(Case 3),as defined in Table 2.As a comparison, the Case 1 color differences are plotted by red(MS)and blue (RGB) dashed lines.

    Of course, the real CSST observations will be definitely somehow different from what we have evaluated in this work.For example,although Tables 2 and 3 report that the color band of Mf555w-Mf814wcan disentangle MPs with different CNO abundances, their color differences are only Δ(Mf555w-Mf814w)~0.006 mag. Such a small color difference can be easily contaminated by unresolved binaries, blending, differential reddening and point-spread function (PSF) fitting residuals. Because of this, a suitable filter does not mean an optimal selection for studying MPs with certain chemical patterns. Anyhow, our analysis definitely shows that MCI/CSST will be a powerful tool for studying MPs in GCs. This work can serve as guidance for arranging future MCI/CSST observations, such as the choice of filter sets and benchmark GCs.

    Acknowledgments

    This work was supported by the National Natural Science Foundation of China (NSFC, Grant No. 12073090), and the China Manned Space Project with NO.CMS-CSST-2021-A08,CMS-CSST-2021-B03. We thank Dr. Licai Deng for expertly commenting on the paper. We thank Dr. Yang Chen for calculating bolometric corrections.

    猜你喜歡
    王悅海峰
    以牙還牙
    Progress and challenges in magnetic skyrmionics
    活著
    歌海(2022年1期)2022-03-29 21:39:55
    倪海峰
    兒童大世界(2019年3期)2019-04-11 03:33:38
    Information Leakage in Quantum Dialogue by Using Non-Symmetric Quantum Channel?
    80后“新貴”王悅:中國(guó)最年輕富豪煉成記
    拳擊戀人不能碰?男友力KO接觸恐懼癥
    Cryptanalysis of Controlled Mutual Quantum Entity Authentication Using Entanglement Swapping?
    My School
    愛是彼此成全
    精品久久久久久成人av| 欧美日韩中文字幕国产精品一区二区三区| 欧美乱色亚洲激情| 精品人妻熟女av久视频| 99久久无色码亚洲精品果冻| 深爱激情五月婷婷| 国产精品爽爽va在线观看网站| 一级毛片久久久久久久久女| 欧美激情在线99| 欧美乱妇无乱码| 国产亚洲精品久久久久久毛片| 99视频精品全部免费 在线| 国产精品久久久久久久电影| 国产精品综合久久久久久久免费| 日韩精品青青久久久久久| 2021天堂中文幕一二区在线观| 精品久久久久久,| 国产免费av片在线观看野外av| 免费av毛片视频| av欧美777| 女生性感内裤真人,穿戴方法视频| 一区二区三区免费毛片| 99久国产av精品| 亚洲人成电影免费在线| 国产探花在线观看一区二区| 国产伦一二天堂av在线观看| 91久久精品电影网| 久久久久久久久久黄片| 精品欧美国产一区二区三| 精品久久久久久久久久久久久| 757午夜福利合集在线观看| 两个人的视频大全免费| 日本五十路高清| avwww免费| 三级国产精品欧美在线观看| 国产午夜福利久久久久久| 级片在线观看| 久久久久久久久久成人| 久久久久国产精品人妻aⅴ院| 色哟哟哟哟哟哟| av天堂在线播放| 日本精品一区二区三区蜜桃| av在线天堂中文字幕| 成人无遮挡网站| 很黄的视频免费| 中出人妻视频一区二区| 亚洲一区高清亚洲精品| 高潮久久久久久久久久久不卡| 日本熟妇午夜| 精品人妻偷拍中文字幕| 久久人妻av系列| av黄色大香蕉| 国产精品永久免费网站| 天堂网av新在线| 免费黄网站久久成人精品 | 精品一区二区免费观看| 国产成年人精品一区二区| 亚洲国产欧洲综合997久久,| a级毛片免费高清观看在线播放| 一级毛片久久久久久久久女| 久久久久九九精品影院| 国产人妻一区二区三区在| 人妻久久中文字幕网| netflix在线观看网站| 免费人成在线观看视频色| 窝窝影院91人妻| 亚洲av成人精品一区久久| 国产又黄又爽又无遮挡在线| 精品午夜福利视频在线观看一区| 一本精品99久久精品77| 免费一级毛片在线播放高清视频| 一本综合久久免费| 永久网站在线| 12—13女人毛片做爰片一| 精品一区二区三区视频在线观看免费| 亚洲,欧美精品.| 桃红色精品国产亚洲av| 男女那种视频在线观看| 日韩免费av在线播放| 麻豆国产97在线/欧美| 简卡轻食公司| 欧美潮喷喷水| 午夜福利18| 一级毛片久久久久久久久女| 丰满人妻熟妇乱又伦精品不卡| 国产精品1区2区在线观看.| 色综合亚洲欧美另类图片| 欧美xxxx黑人xx丫x性爽| 国产av一区在线观看免费| 亚洲人成网站在线播放欧美日韩| 久久精品影院6| 欧美色视频一区免费| 免费观看精品视频网站| 此物有八面人人有两片| 岛国在线免费视频观看| 国产又黄又爽又无遮挡在线| 久久欧美精品欧美久久欧美| 欧美一区二区亚洲| 日本在线视频免费播放| 日本免费一区二区三区高清不卡| 黄色视频,在线免费观看| 可以在线观看的亚洲视频| 给我免费播放毛片高清在线观看| 又爽又黄无遮挡网站| 国产伦一二天堂av在线观看| 久久久久久久久大av| 高清毛片免费观看视频网站| 国产激情偷乱视频一区二区| 无遮挡黄片免费观看| 我要搜黄色片| 精品久久久久久久久久久久久| 亚洲专区国产一区二区| 亚洲成人精品中文字幕电影| 成人一区二区视频在线观看| 国产亚洲精品综合一区在线观看| 中文在线观看免费www的网站| 国产午夜精品论理片| 黄色一级大片看看| 亚洲欧美日韩无卡精品| 九色成人免费人妻av| 国产精品久久久久久人妻精品电影| 国产精品亚洲av一区麻豆| 国产综合懂色| 网址你懂的国产日韩在线| av在线观看视频网站免费| 国产高清视频在线观看网站| 狠狠狠狠99中文字幕| 亚洲最大成人手机在线| 午夜福利成人在线免费观看| 免费一级毛片在线播放高清视频| 精品不卡国产一区二区三区| 免费看a级黄色片| 国产精品久久久久久精品电影| www.999成人在线观看| 有码 亚洲区| 久久6这里有精品| 欧美在线一区亚洲| 一进一出抽搐动态| 中文字幕免费在线视频6| 亚洲av中文字字幕乱码综合| 免费无遮挡裸体视频| 婷婷精品国产亚洲av| 精品人妻1区二区| 五月玫瑰六月丁香| 最近最新免费中文字幕在线| 夜夜夜夜夜久久久久| 久久国产精品人妻蜜桃| 日韩精品中文字幕看吧| 日韩免费av在线播放| 精品午夜福利在线看| 性插视频无遮挡在线免费观看| 中文字幕精品亚洲无线码一区| 日韩大尺度精品在线看网址| h日本视频在线播放| 亚洲精品一区av在线观看| 久久久久久国产a免费观看| 久久久久九九精品影院| 黄色丝袜av网址大全| 久久久久国产精品人妻aⅴ院| 一区福利在线观看| 国产亚洲av嫩草精品影院| 欧美最黄视频在线播放免费| 日韩成人在线观看一区二区三区| 1024手机看黄色片| 两性午夜刺激爽爽歪歪视频在线观看| 在线免费观看的www视频| 亚洲精华国产精华精| 又黄又爽又刺激的免费视频.| 人妻夜夜爽99麻豆av| or卡值多少钱| 欧美另类亚洲清纯唯美| 国产高清视频在线播放一区| 国产一区二区激情短视频| bbb黄色大片| 91在线观看av| 国产91精品成人一区二区三区| 亚洲精品久久国产高清桃花| 9191精品国产免费久久| 久久久成人免费电影| 久久午夜亚洲精品久久| 真人做人爱边吃奶动态| 久久99热这里只有精品18| 色精品久久人妻99蜜桃| 国产av一区在线观看免费| 好男人电影高清在线观看| 欧美激情在线99| 免费在线观看日本一区| 在线观看免费视频日本深夜| 精品免费久久久久久久清纯| 亚洲欧美日韩高清在线视频| 热99在线观看视频| 美女高潮的动态| av天堂中文字幕网| 偷拍熟女少妇极品色| 丰满人妻熟妇乱又伦精品不卡| 在线观看av片永久免费下载| 高清毛片免费观看视频网站| 国内精品一区二区在线观看| 亚洲精品粉嫩美女一区| 久久久久精品国产欧美久久久| 欧美+亚洲+日韩+国产| 亚洲欧美日韩卡通动漫| 日本一本二区三区精品| 久久精品夜夜夜夜夜久久蜜豆| 国产精品嫩草影院av在线观看 | 人妻久久中文字幕网| 欧美日韩黄片免| 18禁在线播放成人免费| 国产av麻豆久久久久久久| 五月伊人婷婷丁香| 狂野欧美白嫩少妇大欣赏| 久久久久国产精品人妻aⅴ院| 久久人人爽人人爽人人片va | 日韩人妻高清精品专区| 日韩高清综合在线| 18+在线观看网站| 国产高清激情床上av| 久久久国产成人免费| 99国产精品一区二区三区| 欧美精品国产亚洲| 国产成人啪精品午夜网站| 12—13女人毛片做爰片一| 亚洲av熟女| 啦啦啦观看免费观看视频高清| 精品久久久久久,| 男人和女人高潮做爰伦理| 日韩国内少妇激情av| 久久人人爽人人爽人人片va | 99国产极品粉嫩在线观看| 亚洲精品影视一区二区三区av| 免费一级毛片在线播放高清视频| 久久久久久久久久黄片| 蜜桃亚洲精品一区二区三区| 在线观看av片永久免费下载| 亚洲最大成人手机在线| 亚洲专区国产一区二区| 成人午夜高清在线视频| 一级作爱视频免费观看| 9191精品国产免费久久| АⅤ资源中文在线天堂| 男女那种视频在线观看| 精品一区二区免费观看| 国产成人欧美在线观看| ponron亚洲| 一区二区三区免费毛片| 国产毛片a区久久久久| 国产成人福利小说| 乱码一卡2卡4卡精品| 亚洲真实伦在线观看| 国产成人影院久久av| 搞女人的毛片| 女生性感内裤真人,穿戴方法视频| 直男gayav资源| 人人妻,人人澡人人爽秒播| 成人无遮挡网站| 国产熟女xx| 亚洲精品色激情综合| 成人鲁丝片一二三区免费| 国产午夜福利久久久久久| 69av精品久久久久久| 赤兔流量卡办理| 日韩欧美三级三区| 日本在线视频免费播放| 午夜a级毛片| 两人在一起打扑克的视频| 在线观看66精品国产| 久久精品综合一区二区三区| 九色国产91popny在线| 婷婷色综合大香蕉| 亚洲人成伊人成综合网2020| 好男人电影高清在线观看| 免费观看人在逋| 天堂网av新在线| 久久亚洲精品不卡| 欧美日韩亚洲国产一区二区在线观看| 久久欧美精品欧美久久欧美| 色精品久久人妻99蜜桃| 在线十欧美十亚洲十日本专区| 久久久成人免费电影| 成年女人毛片免费观看观看9| 免费在线观看影片大全网站| 嫩草影院入口| 欧美高清成人免费视频www| 精品乱码久久久久久99久播| 一卡2卡三卡四卡精品乱码亚洲| 国产精品综合久久久久久久免费| 国产精品一及| 精品欧美国产一区二区三| 欧美日本视频| av国产免费在线观看| 99久久无色码亚洲精品果冻| 精品人妻一区二区三区麻豆 | 亚洲av一区综合| 国产成人啪精品午夜网站| 黄色日韩在线| 热99在线观看视频| 成人午夜高清在线视频| 国产 一区 欧美 日韩| 国产乱人视频| 亚洲最大成人av| 国产中年淑女户外野战色| 色综合婷婷激情| 丁香欧美五月| 午夜福利在线观看吧| 日韩欧美国产在线观看| 成人毛片a级毛片在线播放| 亚洲av一区综合| 天堂影院成人在线观看| 午夜两性在线视频| 国产av不卡久久| 欧美黑人欧美精品刺激| 日本精品一区二区三区蜜桃| 日本撒尿小便嘘嘘汇集6| 在线a可以看的网站| 欧美黑人欧美精品刺激| 蜜桃亚洲精品一区二区三区| 我的老师免费观看完整版| 免费看美女性在线毛片视频| xxxwww97欧美| 白带黄色成豆腐渣| 亚洲av成人av| 成年免费大片在线观看| 黄色日韩在线| 国产精品爽爽va在线观看网站| 欧洲精品卡2卡3卡4卡5卡区| 国产一区二区三区视频了| 国产91精品成人一区二区三区| 少妇人妻精品综合一区二区 | 又黄又爽又刺激的免费视频.| 日韩精品青青久久久久久| 一个人观看的视频www高清免费观看| 国内精品久久久久精免费| 精品人妻1区二区| 亚洲七黄色美女视频| 免费av观看视频| 波多野结衣高清作品| av在线老鸭窝| www.999成人在线观看| 十八禁国产超污无遮挡网站| 日本精品一区二区三区蜜桃| 看免费av毛片| 88av欧美| 天堂网av新在线| 欧美黑人欧美精品刺激| 看免费av毛片| 久久久久久久午夜电影| 午夜视频国产福利| 午夜福利免费观看在线| 中文资源天堂在线| 美女xxoo啪啪120秒动态图 | 一边摸一边抽搐一进一小说| 国产白丝娇喘喷水9色精品| 51午夜福利影视在线观看| 欧美日本视频| 美女xxoo啪啪120秒动态图 | 一边摸一边抽搐一进一小说| 亚洲中文字幕日韩| 国产成人影院久久av| 亚洲专区国产一区二区| 久久久久国内视频| 小说图片视频综合网站| 亚洲五月天丁香| 婷婷精品国产亚洲av| 日本 欧美在线| 婷婷精品国产亚洲av| 日本 欧美在线| 免费av不卡在线播放| 国产精品久久久久久人妻精品电影| 国产精品国产高清国产av| 69av精品久久久久久| 日韩精品中文字幕看吧| 一个人观看的视频www高清免费观看| 老熟妇乱子伦视频在线观看| 日韩欧美精品免费久久 | 久久久国产成人免费| 麻豆久久精品国产亚洲av| 久久久国产成人免费| 一区二区三区高清视频在线| 国产成人aa在线观看| 久久久久久九九精品二区国产| 国产精品嫩草影院av在线观看 | 久久人人精品亚洲av| 亚洲欧美激情综合另类| 搡老岳熟女国产| 精品午夜福利视频在线观看一区| 久久精品国产亚洲av香蕉五月| 欧洲精品卡2卡3卡4卡5卡区| 国产精品免费一区二区三区在线| 淫妇啪啪啪对白视频| 男女床上黄色一级片免费看| 久久久精品大字幕| 美女高潮喷水抽搐中文字幕| 淫妇啪啪啪对白视频| 国产国拍精品亚洲av在线观看| 成人一区二区视频在线观看| 淫秽高清视频在线观看| 色综合婷婷激情| 90打野战视频偷拍视频| 久久精品国产亚洲av涩爱 | 51午夜福利影视在线观看| 亚洲最大成人中文| 中国美女看黄片| 久久国产精品影院| 成年人黄色毛片网站| 国产高潮美女av| 美女 人体艺术 gogo| 人人妻人人澡欧美一区二区| 亚洲av电影不卡..在线观看| 高清日韩中文字幕在线| 亚洲欧美日韩高清在线视频| 综合色av麻豆| 国产精品99久久久久久久久| 99国产精品一区二区蜜桃av| 亚洲av二区三区四区| 高清毛片免费观看视频网站| 久久久久久九九精品二区国产| 中文字幕精品亚洲无线码一区| 国产三级在线视频| 色综合欧美亚洲国产小说| 国内揄拍国产精品人妻在线| 十八禁国产超污无遮挡网站| 成人特级av手机在线观看| 18+在线观看网站| 免费观看人在逋| 亚洲av五月六月丁香网| 毛片女人毛片| 久久久久亚洲av毛片大全| 桃色一区二区三区在线观看| 中文字幕人成人乱码亚洲影| 精品久久久久久久久久久久久| 欧美黑人欧美精品刺激| 国产亚洲精品综合一区在线观看| av视频在线观看入口| 在线观看66精品国产| 毛片女人毛片| 午夜福利在线在线| 婷婷丁香在线五月| 日韩欧美三级三区| 午夜免费男女啪啪视频观看 | 久久久久久久午夜电影| 老司机深夜福利视频在线观看| 亚洲七黄色美女视频| 日韩中字成人| 美女高潮喷水抽搐中文字幕| 婷婷丁香在线五月| 又紧又爽又黄一区二区| 极品教师在线免费播放| 久久精品国产99精品国产亚洲性色| 12—13女人毛片做爰片一| 国产精品久久视频播放| 国产伦在线观看视频一区| 一二三四社区在线视频社区8| 夜夜夜夜夜久久久久| av天堂中文字幕网| 亚洲国产欧美人成| 亚洲欧美精品综合久久99| 婷婷精品国产亚洲av在线| 欧美一区二区亚洲| 在线播放无遮挡| 欧美性猛交黑人性爽| 真人做人爱边吃奶动态| 日日干狠狠操夜夜爽| 亚洲精品一卡2卡三卡4卡5卡| 一本一本综合久久| av天堂在线播放| 中文字幕免费在线视频6| 日韩欧美三级三区| 欧美日本视频| 久久天躁狠狠躁夜夜2o2o| 永久网站在线| 最新在线观看一区二区三区| 久久亚洲精品不卡| 欧美一级a爱片免费观看看| 97超视频在线观看视频| 高清在线国产一区| 人妻丰满熟妇av一区二区三区| 精品久久久久久,| 99精品久久久久人妻精品| 亚洲国产高清在线一区二区三| 嫩草影院新地址| 91狼人影院| 最近视频中文字幕2019在线8| 好看av亚洲va欧美ⅴa在| 琪琪午夜伦伦电影理论片6080| 国产av麻豆久久久久久久| 欧美日韩中文字幕国产精品一区二区三区| 看片在线看免费视频| 99在线人妻在线中文字幕| 97超级碰碰碰精品色视频在线观看| 国产老妇女一区| 亚洲aⅴ乱码一区二区在线播放| 搡老熟女国产l中国老女人| 99在线人妻在线中文字幕| 看免费av毛片| 亚洲熟妇熟女久久| 又黄又爽又刺激的免费视频.| 黄片小视频在线播放| 99久久成人亚洲精品观看| 国产免费av片在线观看野外av| 直男gayav资源| 热99在线观看视频| 免费黄网站久久成人精品 | 最近在线观看免费完整版| 日韩中文字幕欧美一区二区| 桃红色精品国产亚洲av| 一区二区三区激情视频| 亚洲精华国产精华精| 精品不卡国产一区二区三区| 精品久久久久久久末码| 国产黄片美女视频| 欧美zozozo另类| 熟妇人妻久久中文字幕3abv| av在线天堂中文字幕| 日日摸夜夜添夜夜添av毛片 | 亚洲五月天丁香| av天堂中文字幕网| 欧美成人a在线观看| 亚洲av五月六月丁香网| 99精品久久久久人妻精品| av中文乱码字幕在线| 美女高潮的动态| eeuss影院久久| 日本三级黄在线观看| 国产精品av视频在线免费观看| 中文字幕av成人在线电影| 欧美成人一区二区免费高清观看| 午夜日韩欧美国产| 亚洲av日韩精品久久久久久密| 在线观看舔阴道视频| 日日干狠狠操夜夜爽| 午夜免费男女啪啪视频观看 | 久久久久免费精品人妻一区二区| 国产黄色小视频在线观看| 亚洲va日本ⅴa欧美va伊人久久| 日本a在线网址| 久久国产精品影院| 在现免费观看毛片| 欧美+亚洲+日韩+国产| 国产69精品久久久久777片| 丁香欧美五月| 亚洲av电影不卡..在线观看| 少妇丰满av| 亚洲国产精品久久男人天堂| 亚洲精品色激情综合| 麻豆一二三区av精品| 国产精品自产拍在线观看55亚洲| 91在线观看av| 搡老妇女老女人老熟妇| 色5月婷婷丁香| 超碰av人人做人人爽久久| 亚洲中文日韩欧美视频| 亚洲性夜色夜夜综合| 91九色精品人成在线观看| 最近中文字幕高清免费大全6 | 九色国产91popny在线| 亚洲激情在线av| 欧美一级a爱片免费观看看| 亚洲av电影在线进入| 麻豆一二三区av精品| 偷拍熟女少妇极品色| 黄色配什么色好看| 欧美极品一区二区三区四区| eeuss影院久久| 99久久成人亚洲精品观看| 五月玫瑰六月丁香| 成人精品一区二区免费| 国产一区二区在线av高清观看| 成人欧美大片| 99国产综合亚洲精品| 天天一区二区日本电影三级| 亚洲五月天丁香| 日本黄大片高清| 狂野欧美白嫩少妇大欣赏| 亚洲国产精品sss在线观看| 国产精品永久免费网站| 久久精品影院6| 搡老熟女国产l中国老女人| 欧美成人a在线观看| 麻豆久久精品国产亚洲av| 免费在线观看亚洲国产| 亚洲成人中文字幕在线播放| 免费黄网站久久成人精品 | 欧洲精品卡2卡3卡4卡5卡区| 琪琪午夜伦伦电影理论片6080| 女同久久另类99精品国产91| 国产亚洲欧美98| 久久精品影院6| 国产精品1区2区在线观看.| 桃色一区二区三区在线观看| 亚洲av成人av| 欧美最新免费一区二区三区 | 日本黄色视频三级网站网址| 精品日产1卡2卡| 国产精品爽爽va在线观看网站| 夜夜看夜夜爽夜夜摸| 亚洲一区高清亚洲精品| 国产成人福利小说| 女同久久另类99精品国产91| 亚洲第一欧美日韩一区二区三区| 床上黄色一级片| 亚洲精品一卡2卡三卡4卡5卡| 日本撒尿小便嘘嘘汇集6| 男女床上黄色一级片免费看| 网址你懂的国产日韩在线| 国内精品久久久久久久电影| 亚洲精品色激情综合| 欧美不卡视频在线免费观看| 日韩 亚洲 欧美在线| 在线免费观看的www视频| 日韩欧美在线乱码| 天美传媒精品一区二区| 国产熟女xx| 精品人妻偷拍中文字幕| 国内精品久久久久久久电影| 亚洲成人中文字幕在线播放|