- ID:
- ivo://CDS.VizieR/J/ApJ/786/2
- Title:
- Spitzer photometric time series of HD 97658
- Short Name:
- J/ApJ/786/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present here the confirmation, based on Spitzer transit observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass (M_*_=0.77+/-0.05 M_{sun}_) K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck-High Resolution Echelle Spectrometer (Keck-HIRES) radial velocities and Microvariability and Oscillations of STars (MOST) and Spitzer photometry. HD 97658 b is a massive (M_p_=7.55_-0.79_^+0.83^ M_{earth}_) and large (R_p_=2.247_0.095_^+0.098^ R_{earth}_ at 4.5 {mu}m) super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, of at least 60% by mass, and very little H-He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age. Orbiting a bright host star, HD 97658 b will be a key target for upcoming space missions such as the Transiting Exoplanet Survey Satellite (TESS), the Characterizing Exoplanet Satellite (CHEOPS), the Planetary Transits and Oscillations of stars (PLATO), and the James Webb Space Telescope to characterize thoroughly its structure and atmosphere.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/654/338
- Title:
- Spitzer photometry in W3 molecular cloud
- Short Name:
- J/ApJ/654/338
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new images of the giant molecular cloud W3 obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope. The images encompass the star forming regions W3 Main, W3(OH), and a region that we refer to as the Central Cluster, which encloses the emission nebula IC 1795. We present a star count analysis of the point sources detected in W3. The star count analysis shows that the stellar population of the Central Cluster, when compared to that in the background, contains an over density of sources. The Central Cluster also contains an excess of sources with colors consistent with Class II young stellar objects (YSOs). An analysis of the color-color diagrams also reveals a large number of Class II YSOs in the Central Cluster. Our results suggest that an earlier epoch of star formation created the Central Cluster, created a cavity, and triggered the active star formation in the W3 Main and W3(OH) regions. We also detect a new outflow and its candidate exciting star.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/1150
- Title:
- Spitzer photometry of globulars in 2 galaxies
- Short Name:
- J/MNRAS/389/1150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spitzer IR Array Camera (IRAC) mid-infrared photometry is presented for the globular cluster (GC) systems of the NGC 5128 ('Centaurus A') and NGC 4594 ('Sombrero') galaxies. Existing optical photometric and spectroscopic are combined with this new data in a comprehensive optical-to-mid-IR colour catalogue of 260 GCs. Empirical colour-metallicity relationships are derived for all optical-to-mid-IR colour combinations.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/76
- Title:
- Spitzer photometry of LMC Cepheids
- Short Name:
- J/ApJ/743/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carnegie Hubble Program is designed to improve the extragalactic distance scale using data from the post-cryogenic era of Spitzer. The ultimate goal is a determination of the Hubble constant to an accuracy of 2%. This paper is the first in a series on the Cepheid population of the Large Magellanic Cloud, and focusses on the period-luminosity (PL) relations (Leavitt laws) that will be used, in conjunction with observations of Milky Way Cepheids, to set the slope and zero point of the Cepheid distance scale in the mid-infrared. To this end, we have obtained uniformly sampled light curves for 85 LMC Cepheids, having periods between 6 and 140 days. PL and period-color relations are presented in the 3.6um and 4.5um bands. We demonstrate that the 3.6um band is a superb distance indicator. The cyclical variation of the [3.6]-[4.5] color has been measured for the first time. We attribute the amplitude and phase of the color curves to the dissociation and recombination of CO molecules in the Cepheid's atmosphere. The CO affects only the 4.5um flux making it a potential metallicity indicator.
- ID:
- ivo://CDS.VizieR/J/A+A/476/1161
- Title:
- Spitzer photometry of M33
- Short Name:
- J/A+A/476/1161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Combining the relative vicinity of the Local Group spiral galaxy M33 with the Spitzer images, we investigate the properties of infrared (IR) emission sites and assess the reliability of the IR emission as a star formation tracer. The mid- and far-IR emission of M33 was obtained from IRAC and MIPS images from the Spitzer archive. We compared the photometric results for several samples of three known types of discrete sources (HII regions, supernovae remnants and planetary nebulae) with theoretical diagnostic diagrams, and derived the spectral energy distribution (from 3.6 to 24{mu}m) of each type of object. Moreover, we generated a catalogue of 24{mu}m sources and inferred their nature from the observed and theoretical colours of the known type sources. We estimated the star formation rate in M33 both globally and locally, from the IR emission and from the Halpha emission line.
- ID:
- ivo://CDS.VizieR/J/ApJS/228/5
- Title:
- Spitzer photometry of ~1million stars in M31 & 15 gal.
- Short Name:
- J/ApJS/228/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer IRAC 3.6-8{mu}m and Multiband Imaging Photometer 24{mu}m point-source catalogs for M31 and 15 other mostly large, star-forming galaxies at distances ~3.5-14Mpc, including M51, M83, M101, and NGC 6946. These catalogs contain ~1 million sources including ~859000 in M31 and ~116000 in the other galaxies. They were created following the procedures described in Khan et al. (2015, J/ApJS/219/42) through a combination of point-spread function (PSF) fitting and aperture photometry. These data products constitute a resource to improve our understanding of the IR-bright (3.6-24{mu}m) point-source populations in crowded extragalactic stellar fields and to plan observations with the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/AJ/133/791
- Title:
- Spitzer photometry of normal & interacting galaxies
- Short Name:
- J/AJ/133/791
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer mid-infrared imaging of a sample of 35 tidally distorted premerger interacting galaxy pairs selected from the Arp Atlas. We compare their global mid-infrared properties with those of normal galaxies from the SINGS Spitzer Legacy survey, and separate the disk emission from that of the tidal features. The [8.0um]-[24um], [3.6um]-[24um], and [5.8um]-[8.0um] colors of these optically selected interacting galaxies are redder on average than those of spirals, implying enhancements to the mass-normalized star formation rates (SFRs) of a factor of ~2.
- ID:
- ivo://CDS.VizieR/J/ApJ/643/965
- Title:
- Spitzer photometry of the Trifid nebula (M20)
- Short Name:
- J/ApJ/643/965
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spitzer IRAC and MIPS images of the Trifid Nebula (M20) reveal its spectacular appearance in infrared light, highlighting the nebula's special evolutionary stage. The images feature recently formed massive protostars and numerous young stellar objects, and a single O star that illuminates the surrounding molecular cloud from which it formed, and unveil large-scale, filamentary dark clouds. Multiple protostars are detected in the infrared, within the cold dust cores of TC3 and TC4, which were previously defined as Class 0. The cold dust continuum cores of TC1 and TC2 contain only one protostar each. The Spitzer color-color diagram allowed us to identify 160 young stellar objects (YSOs) and classify them into different evolutionary stages. The diagram also revealed a unique group of YSOs that are bright at 24um but have the spectral energy distribution peaking at 58um.
- ID:
- ivo://CDS.VizieR/J/A+A/534/A96
- Title:
- Spitzer photometry of YSC in M33
- Short Name:
- J/A+A/534/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The properties of young stellar clusters (YSCs) in M33, identified from the center out to about twice the size of the bright star-forming disk, are investigated to determine possible spatial and time variations of the star formation process in this Local Group blue galaxy. 915 MIR sources have been extracted from the Spitzer 24um image. Upon inspection of H{alpha} and GALEX images and exclusion of evolved AGB stars, a sample of 648 objects is selected as candidate YSCs and their luminosity function is examined. The spectral energy distribution of each object, based on aperture photometry, is compared with Starburst99 models to derive age, mass and AV of individual clusters. In the analysis we allow for different values of the upper mass cutoff of the stellar initial mass function (IMF), the porosity of the ISM, and the dustiness of HII regions. We also examine the influence of different dust models and include corrections for incompleteness of the IMF.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/42
- Title:
- Spitzer point source catalogs in 7 nearby gal.
- Short Name:
- J/ApJS/219/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer IRAC 3.6-8{mu}m and Multiband Imaging Photometer 24{mu}m point-source catalogs for seven galaxies: NGC6822, M33, NGC300, NGC2403, M81, NGC0247, and NGC7793. The catalogs contain a total of ~300000 sources and were created by dual-band selection of sources with >3{sigma} detections at both 3.6 and 4.5{mu}m. The source lists become significantly incomplete near m_3.6_=m_4.5~=18. We complement the 3.6 and 4.5{mu}m fluxes with 5.8, 8.0, and 24{mu}m fluxes or 3{sigma} upper limits using a combination of PSF and aperture photometry. This catalog is a resource as an archive for studying mid-infrared transients and for planning observations with the James Webb Space Telescope.
