How old are you?

Michael Küffmeier (Marie Skłodowska-Curie global fellow)

Rejuvenation of disks by (late) infall

Sigurd Jensen, Jaime Pineda, Paola Caselli (all MPE), Troels Haugbølle (NBI)

Wow!

Credit: ALMA (ESO/NAOJ/NRAO)

Credit:

DSHARP team

10 au

50 au

The classical picture

Greene 2001

star formation

planet formation

Is this the full picture?

Credit: ALMA (ESO/NAOJ/NRAO)

Ginski et al. 2021

Yen et al. 2019

Garufi et al. 2021

Pineda et al. 2020

50 au

see also:

BHB1 (Alves et al. 2020), GM Aur (Huang et al. 2021), IRS 63 (Segura-Cox in prep.), AB Aur (Grady et al. 1999 / Fukagawa et al. 2004), ...

Per-emb-50

Valdivia-Mena et al. 2022

Model star formation in its birth environment

magnetohydrodynamical (MHD), adaptive mesh refinement (AMR) simulations with RAMSES; maximum resolution 25 AU; 3000 solar masses

x

y

1 pc

Late infall is common for stars*

*unless they are tiny

On average, stars with final masses of more than 1 solar mass accrete more than 50 % of their mass after 500 kyr

Almost 20 % of stars more massive than 1 solar mass accrete 50 % of their mass after 1 Myr

Origin of accreting gas

For solar mass stars ~50 % of final mass from beyond prestellar core! (Pelkonen et al. 2021)

Possibility of replenishing and refreshing the mass and chemical budget

Class II

Class I

Class 0

YSOs can appear younger than they really are

How old is the protostar?

A poor analogy to this morning

Session start

My talk

Coffee break!

Class II

Class I

Class 0

Streamers (and shadows?) as signs of infall

Formation of misaligned configuration

Observable as shadows in outer disk

Ginski et al. 2021

Küffmeier, Dullemond et al. 2021

see also Bate 2018

Summary

Pineda ... Küffmeier et al. 'Protostars and Planets VII'

.

.

Segura-Cox et al. in prep.

Star & disk can be replenished by infall of initially unbound material

YSOs can be rejuvenated

Late infall happens more often than assumed

For solar mass stars ~50 % of final mass from beyond prestellar core! (Pelkonen et al. 2021)

Can disks be rejuvenated?

Küffmeier et al. 2022 in prep

Possibility of replenishing and refreshing the mass and chemical budget

It's fun to work on cosmic rays,

instead of catching Covid waves.

Does cosmic-ray ionization play a crucial role in disk formation?

The connection to the larger scales

Küffmeier et al. 2017 / 2022 in prep.

Gas from beyond the prestellar core can fall onto the star-disk system

Simulate cloudlet infall onto disk

AREPO, pure hydrodynamical

R_{\rm i,d}=50\, \rm au

\Sigma(r) = 170 \left(\frac{\rm g}{\rm cm}\right)^{2} \left( \frac{r}{1 \rm au} \right)^{-3/2}

M_{\rm cloudlet}(R_{\rm cloudlet}) = 0.01 {\rm M}_{\odot} \left( \frac{R_{\rm cloudlet}}{5000 \rm au}\right)^{2.3}

R_{\rm cloudlet} = 887\, \rm au

isothermal gas

vary infalling angle

\alpha = 0^{\circ} (35^{\circ}, 60^{\circ}, 90^{\circ})

b = 1774\, \rm au

vary rotation (prograde, retrograde)

Küffmeier, Dullemond, Reißl, Goicovic et al. 2021

M_{*}=2.5\, \mathrm{M}_{\odot}

Outer disk forms around inner disk

Küffmeier et al. 2021

Prograde vs. retrograde infall

Retrograde infall causes:

counter-rotating inner and outer disk

shrinking of inner disk

enhanced accretion

larger and deeper gap between disks

see also Vorobyov+ 2016

Küffmeier et al. 2021

Inner disk orientation

M_{\rm i, disk}=4 \ M_{\rm cloudlet}

M_{\rm cloudlet} = 1.87 \times 10^{-4} \ \mathrm{M}_{\odot}

M_{\rm i,disk} = 24 M_{\rm cloudlet}

M_{\rm i,disk}=4 \ M_{\rm cloudlet}

M_{\rm i,disk} = 0.4 \ M_{\rm cloudlet}

Küffmeier et al. 2021