Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Searching for biosignatures in exoplanetary impact ejecta
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
Vise andre og tillknytning
(engelsk)Inngår i: Astrobiology, ISSN 1531-1074, E-ISSN 1557-8070Artikkel i tidsskrift (Fagfellevurdert) Submitted
Emneord [en]
Biosignatures, Exoplanets, Impacts, Interplanetary dust, Remote sensing
HSV kategori
Forskningsprogram
astronomi
Identifikatorer
URN: urn:nbn:se:su:diva-127262OAI: oai:DiVA.org:su-127262DiVA, id: diva2:907805
Tilgjengelig fra: 2016-02-29 Laget: 2016-02-29 Sist oppdatert: 2022-02-23bibliografisk kontrollert
Inngår i avhandling
1. Debris disks and the search for life in the universe
Åpne denne publikasjonen i ny fane eller vindu >>Debris disks and the search for life in the universe
2016 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Circumstellar debris disks are the extrasolar analogues of the asteroid belt and the Kuiper belt. These disks consist of comets and leftover planetesimals that continuously collide to produce copious amounts of circumstellar dust that can be observed as infrared excess or in resolved imaging. As an obvious outcome of the planet formation process, debris disks can help us constrain planet formation theories and learn about the history of our own solar system. Structures in the disks such as gaps or warps can hint at the presence of planets. Thus, the study of debris disks is an important branch of exoplanetary science. In this thesis, some aspects of debris disks are considered in detail.

A handful of debris disks show observable amounts of gas besides the dust. One such case is the edge-on debris disk around the young A-type star β Pictoris, where the gas is thought to be of secondary origin, i.e. derived from the dust itself. By observing this gas, we can thus learn something about the dust, and therefore about the building blocks of planets. In paper I, spectrally resolved observations of C II emission with Herschel/HIFI are presented. The line profile is used to constrain the spatial distribution of carbon gas in the disk, which helps understanding the gas producing mechanism. In paper II, we analyse C II and O I emission detected with Herschel/PACS and find that the oxygen must be located in a relatively dense region, possibly similar to the CO clump seen by ALMA. An upcoming analysis of our ALMA C I observations will give us a clearer picture of the system.

Another famous debris disk is found around the nearby, 440 Myr old A-star Fomalhaut. Its morphology is that of an eccentric debris belt with sharp edges, suggesting shaping by a planet. However, gas-dust interactions may result in a similar morphology without the need to invoke planets. We test this possibility in paper III by analysing non-detections of C II and O I emission by Herschel/PACS. We find that there is not enough gas present to efficiently sustain gas-dust interactions, implying that the morphology of the Fomalhaut belt is due to a yet unseen planet or alternatively stellar encounters.

One of the biggest challenges in exoplanetary research is to answer the question whether there are inhabited worlds other than the Earth. With the number of known rocky exoplanets in the habitable zone increasing rapidly, we might actually be able to answer this question in the coming decades. Different approaches exist to detect the presence of life remotely, for example by studying exoplanetary atmospheres or by analysing light reflected off the surface of an exoplanet. In paper IV, we study whether biosignatures (for example, certain minerals or microorganisms) ejected into a circumstellar debris disk by an impact event could be detected. We consider an impact similar to the Chicxulub event and model the collisional evolution of the ejected debris. Dust from such an event can potentially be detected by current telescopes, but analysis of the debris composition has to wait for future, advanced instruments.

sted, utgiver, år, opplag, sider
Stockholm: Department of Astronomy, Stockholm University, 2016. s. 73
Emneord
debris disks, astrobiology
HSV kategori
Forskningsprogram
astronomi
Identifikatorer
urn:nbn:se:su:diva-127263 (URN)978-91-7649-366-3 (ISBN)
Disputas
2016-04-15, sal FB52, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 4: Submitted.

Tilgjengelig fra: 2016-03-21 Laget: 2016-02-29 Sist oppdatert: 2022-02-23bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Person

Cataldi, GianniBrandeker, AlexisOlofsson, Göran

Søk i DiVA

Av forfatter/redaktør
Cataldi, GianniBrandeker, AlexisOlofsson, Göran
Av organisasjonen
I samme tidsskrift
Astrobiology

Søk utenfor DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric

urn-nbn
Totalt: 139 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf