Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two “Baby” beta Pics
1998 Authors: Michael L. Sitko, Carol A. Grady, David K. Lynch, Ray W. Russell, Martha S. Hanner

https://arxiv.org/abs/astro-ph/9807229

Page 4: “crystalline olivine condenses at the high temperatures (>1200 K) that might have been typical of the inner solar nebula,”
“This scenario requires that these grains then be transported to the
region of comet formation and be mixed with ice grains that probably condensed at temperatures below 30 K (Crovisier et al. 1997).”

Explanation: Olivine Crystaline form in the planet forming convection cells in the inner solar nebula at high temperature (>1200 K) while ice (grains) will condense in the outer region of the gas/dust disk of the star. Through jets of the star pieces of crystalline olivine are transported to the outer region. The jets will melt the ice. When jets retreats and the region starts to cool below 30 K the ice grains and the crystalline olivine will condense and form the comets.

Meridional flows in the disk around a young star
2019 Authors: Richard Teague, Jaehan Bae, Edwin Bergin

https://www.nature.com/articles/s41586-019-1642-0

Page 1: “Protoplanetary disks are known to posses a stunning variety of
substructure in the distribution of their mm sized grains, predominantly seen as rings and gaps1, which are frequently interpreted as due to the shepherding of large grains by either hidden, still-forming planets within the disk2 or (magneto-)hydrodynamic instabilities 3.”
“To relate the gas velocities to the local sound speed, we use the
brightness temperature of the optically thick line emission as a measure
the local gas temperature5, finding values spanning between ≈ 90 K
in the inner 30 au and dropping to 30 K at 400 au. ”

The Herbig Ae star HD 163296 in X-rays

2005 Authors: Douglas A. Swartz, Jeremy J. Drake, Ronald F. Elsner, Kajal K. Ghosh, Carol A. Grady, Edward Wassell, Bruce E. Woodgate, Randy A. Kimble

Page 1: “HD 163296 is a nearby (122 pc) Herbig Ae star (A1Ve,AV =0.m25) with an effective temperatureTef f=9300 K,luminosity log(L⋆/L⊙)=1.48+0.12−0.10, massM⋆ = 2.3M⊙,and radiusR⋆ = 2.1R⊙ (van den Ancker, de Winter, &Tijn A Djie 1998).

“HD 163296 has a strong infrared excess (Hillenbrand et al. 1992; Meeus et al. 2001) and variable Balmer series emission lines (Baade & Stahl 1989; Pogodin 1994; Beskrovnaya et al. 1998)”

Page 2: “The large infrared excess arises fromheated, optically thick dust within a circumstellar disk(Hillenbrand et al. 1992; Meeus et al. 2001). The disk has a radius of ∼450 AU (3.′′7) viewed at ∼60◦inclination (Mannings & Sargent 1997; Grady et al. 2000). The time-variable double-peaked and P Cygni Balmer and UVemission line profiles arise from a stellar wind, an extended chromosphere, and/or rotation (e.g., Catala et al. 1989).
Radio continuum observations (Brown, Perez, & YusefZadeh 1993) of HD 163296 also suggest wind-driven mass loss. Orthogonal to the disk is an axially-aligned chain
of Herbig-Haro nebulae extending several seconds of arc above and below the disk (Grady et al. 2000). A Lyαbright jet extending 6′′ along the SW arm of the HerbigHaro flow has also been discovered (Devine et al. 2000).”