The formation of planetesimals is expected to occur via particle-gas instabilities that concentrate dust into self-gravitating clumps. Triggering these requires the prior pileup in protoplanetary disk. Until now, this has been successfully modeled exclusively at disk's snowline, whereas rocky inner disk were obtained only by assuming either unrealistically large particle sizes or an enhanced gl...

Abstract The water snowline location in protostellar envelopes provides crucial information about the thermal structure and mass accretion process as it can inform occurrence of recent (≲1000 yr) bursts. In addition, ability to image emission makes these sources excellent laboratories test indirect tracers such H 13 CO + . We study five Perseus using a suite molecular-line observations taken wi...

Snow course and SNOTEL measurements of spring snowpack, corroborated by a physically-based hydrologic model, are examined here for climate-driven fluctuations and trends during the period 1916-2002. Much of the mountain West has experienced declines in spring snowpack, especially since mid-century, and despite increases in winter precipitation in many places. Analysis and modeling shows that cl...

Astronomical observations reveal that protoplanetary disks around young stars commonly have ring- and gap-like structures in their dust distributions. These features are associated with pressure bumps trapping particles at specific locations, which simulations show ideal sites for planetesimal formation. Here we our Solar System may formed from rings of planetesimals -- created by rather than a...

Abstract The water snowline in circumstellar disks is a crucial component planet formation, but direct observational constraints on its location remain sparse owing to the difficulty of observing both young embedded and mature protoplanetary disks. Chemical imaging provides an alternative route locate snowline, HCO + isotopologues have been shown be good tracers protostellar envelopes Herbig He...

Abstract An end of summer snowline (EOSS) photographic dataset for Aotearoa New Zealand contains over four decades equilibrium line altitude (ELA) observations more than 50 index glaciers. This provides an opportunity to create a climatological ELA reference series that has several applications. Our work screened out EOSS sites had low temporal coverage and also removed limited when the officia...