English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present an overview and first results from a $M$-band spectroscopic surveyof planet-forming disks performed with iSHELL on IRTF, using two slits thatprovide resolving power R $\approx$ 60,000-92,000 (5-3.3 km/s). iSHELL providesa nearly complete coverage at 4.52-5.24 $\mu$m in one shot, covering $>50$lines from the R and P branches of $^{12}$CO and $^{13}$CO for each of multiplevibrational levels, and providing unprecedented information on the excitationof multiple emission and absorption components. Some of the most notable newfindings of this survey are: 1) the detection of two CO Keplerian rings at $<2$au (in HD 259431), 2) the detection of H${_2}$O ro-vibrational lines at 5$\mu$m (in AS 205 N), and 3) the common kinematic variability of CO lines overtimescales of 1-14 years. By homogeneously analyzing this survey together witha previous VLT-CRIRES survey of cooler stars, we discuss a unified view of COspectra where emission and absorption components scan the disk surface acrossradii from a dust-free region within dust sublimation out to $\approx10$ au. Weclassify two fundamental types of CO line shapes interpreted as emission fromKeplerian rings (double-peak lines) and a disk surface plus a low-velocity partof a wind (triangular lines), where CO excitation reflects different emittingregions (and their gas-to-dust ratio) rather than just the irradiationspectrum. A disk+wind interpretation for the triangular lines naturallyexplains several properties observed in CO spectra, including the lineblue-shifts, line shapes that turn into narrow absorption at high inclinations,and the frequency of disk winds as a function of stellar type.

Scanning disk rings and winds in CO at 0.01-10 au: a high-resolution $M$-band spectroscopy survey with IRTF-iSHELL