Astrobiological moleculesin star-forming regions

(hot cores)

Víctor M. RivillaiALMA Fellow, Osservatorio Astrofisico di Arcetri

October 6 2015“From clouds to protoplanetary disks”, Berlin

Image credit: ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO) & NASA/JPL-Caltech/WISE Team

Maite Beltrán, Riccardo Cesaroni, Claudio Codella, Francesco Fontani, Paul Woods, Serena Viti, Paola Caselli, Anton Vasyunin, Hannah Calcutt

Glycolaldehyde (GA) (CH2OHCHO) • The simplest sugar.• It can react with propenal (3-carbon sugar) to produce ribose, the central

constituent of RNA.

Important role in interstellar prebiotic chemistry

+RiboseGlycolaldehyde Propenal

RNA

Ethylene glycol (EG) (CH2OH)2

• The simplest sugar alcohol (sugar + hydrogen atoms)

• The reduced alcohol of glycolaldehyde

The SUGAR family• Sugars or monossacharides are the basic units of

carbohydrates.

The SUGAR family• Still only a few detections…

but increasing interest!

Hollis+00,02, Crovisier04a, Fuente+04, Requena-Torres08, Beltrán+09, Jørgensen+12, Maury+14, Biver+14, Coutens+15, Brouillet+15, Lykke+15, Taquet+15, Rivilla+, in prep.

Hot molecular cores: a perfect laboratory for astrochemistry

• Molecular environment surrounding massive stars (M > 8 Msun)• The most complex molecules have been detected in hot cores• The radiation from the star and/or shocks evaporates the complex

molecules from the grain mantles. • Very rich chemistry.

NASA- Lara Clemence

Complex molecules already detected: CH3OH, CH3CN, CH3CHO, C2H5OH, C2H5CN, CH3OCHO, CH3COCH3... (e.g. Fontani+07, Beltrán+09)

Good candidate for the detection of GA and EG

OUR TARGET: G31.41+0.31 HOT CORE

Fontani+07

Observational campaigns

Wavelength (mm)(mm)

Telescope Frequency range (GHz) beam (arcsec x arcsec)7 GBT 45-46 163 IRAM 30m 81.2-89.0 282 IRAM 30m 167.9-175.7 141 SMA 219.45-221.45

229.35-231.351.7 x 3.5 (com)

0.90 x 0.75 (com + vex)1 PdB 103.63-103.7 4.4 x 5.42 PdB 143.61-143.68 4.1 x 3.23 PdB 220.23-220.50 0.5 x 1.1

• Single dish data wide frequency coverage detection of multiple transitions • Interferometric data spatial information

GBT IRAM 30m Submillimeter Array (SMA) Plateu de Bure (PdB)

Beltrán+09

1.4 mm

2.1 mm

2.9 mm

Detection of glycolaldehyde in G31

• First detection outside the Galactic Center by Beltrán et al. (2009)

PdB o

bserva

tions

Up to 30 “clean” (not blended) lines with Eup=5-113 K

Rivilla et al, in prep.

Detection of ethylene glycol in G31 (single-dish)

MADCUBA (MAdrid Data CUBe Analysis)

LTE simulated spectra

GBT

IRAM 30m

Tex~70 K

Rivilla et al, in prep.

Detection of ethylene glycol in G31 (interferometer)

MADCUBA (MAdrid Data CUBe Analysis)

LTE simulated spectra

GBT

IRAM 30m

Submillimeter Array (SMA)

Tex~70 K

GBT

IRAM 30m

Submillimeter Array (SMA)

MADCUBA (MAdrid Data CUBe Analysis)

LTE simulated spectra

Tex~70 K

Detection of ethylene glycol in G31 (interferometer)

GBT

IRAM 30m

Submillimeter Array (SMA)

MADCUBA (MAdrid Data CUBe Analysis)

LTE simulated spectra

Tex~70 K

Detection of ethylene glycol in G31 (interferometer)

Spatial distribution of GA and EG

• Compact spatial distribution • EG & GA: very similar morphology

GlycolaldehydeCOLOR SCALE = Ethylene glycol

White contours = CH3CN

Rivilla et al, in prep.• Integrated intensity maps of 5 unblended

lines of EG

• Spatial coherence supports identification

Spatial distribution of GA and EG

YELLOW (EG)

CH3CN

Color scale: methyl formate (CH3OCHO)

Black contours: ethanol (CH3CH2OH)

• EG & GA peaks towards the continuum peak

excellent tracers of the gas located closer to the central massive protostar

Better understanding of the star formation process (accretion,

kinematics…)

Kinematics of EG

ethylene glycol

• Velocity map shows a clear gradient interpreted as rotation (Cesaroni+2011)

CH3CN

•COMs are an excellent tool to study the PHYSICS of star formation

Kinematics of EG

ethylene glycol

• Velocity map shows a clear gradient interpreted as rotation (Cesaroni+2011)

CH3CN

•COMs are an excellent tool to study the PHYSICS of star formation

•What about CHEMISTRY? How these molecules were formed?

H CH2OCHO

(CH2OH)2(ethylene glycol)

(F) Woods+13, Fedoseev+15 (D) Beltrán+09,Woods+12

(E) Charnley&Rogers+05Fedoseev+15

(A) Sorrell+01, Woods+12

H

HCO

CH3OH

H2CO

CH2OHCHO(glycolaldehyde)

HCO

HCO

CO+H2CO

HOCCOH (glyoxal)

H

H

CH3O

CH3OH* 2H

HC2O(ketenyl)C

CH2CO(ketene)CH2CHOH

O

OCH2CHOH

HCH2OH

HCO

(B) Bennett&Kaisser07, Garrod+08, Butscher+15

CH2OH

OC2OH

Charnley&Rogers+05

H

O

H

H

HCO

Observations

Chemical (+ physical) models

Laboratory experiments

Joint study is the only way to really understand how COMs are formed in the space

Observations: EG/GA ratio

EG/GA is rather different between sources

EG/GA > 1

Do the differences arise from the origin

(the grains) or are a consequence of subsequent evolution?

Source [EG/GA]Hale-Bopp (comet) >6Lemmon (comet) >3Lovejov (comet) >5IRAS 16293-2422 1NGC 1333 IRAS2A 5NGC7129 FIRS2 2SgrB2N 1.3G31.41+0.31 4Orion hot core >10 W51e2 >16G34.3+0.2 >6G-0.02, G-0.11,G+0.693 1.2-1.6

Hollis+00,02, Crovisier04a, Fuente+04, Requena-Torres08, Beltrán+09, Jørgensen+12, Belloche+13 Maury+14, Biver+14, Coutens+15, Brouillet+15, Lykke+15, Taquet+15, Rivilla+, in prep.

Chemical models and laboratory: EG/GA ratio

Fedoseev+15 Oberg+09

EG/GA<1

EG/GA>1CH3OH:CO EG/GA

Pure CH3OH >10

1:10 < 0.25

Different initial atom H density

OTHER EXPLANATIONS: - Different destruction efficiency in the gas phase? - Different timescales produce different ratios (Garrod+08).

Different compositions of the ices

Astrobiological moleculesin star-forming regions

(hot cores)

Víctor M. RivillaiALMA Fellow, Osservatorio Astrofisico di Arcetri

October 6 2015“From clouds to protoplanetary disks”, Berlin

Image credit: ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO) & NASA/JPL-Caltech/WISE Team

Maite Beltrán, Riccardo Cesaroni, Claudio Codella, Francesco Fontani, Paul Woods, Serena Viti, Paola Caselli, Anton Vasyunin, Hannah Calcutt