Table · dataset · 2023
Convective blueshifts for evolved stars
Listed in IVOA Registry (Virtual Observatory)
With the advent of extreme precision radial velocity (RV) surveys, seeking to detect planets at RV semi-amplitudes of 10cm/s, intrinsic stellar variability is the biggest challenge to detecting small exoplanets.
Description
To overcome the challenge we must first thoroughly understand all facets of stellar variability. Among those, convective blueshift caused by stellar granulation and its suppression through magnetic activity plays a significant role in covering planetary signals in stellar jitter.
Previously we found that for main sequence stars, convective blueshift as an observational proxy for the strength of convection near the stellar surface strongly depends on effective temperature. In this work we investigate 242 post main sequence stars, covering the subgiant, red giant, and asymptotic giant phases and empirically determine the changes in convective blueshift with advancing stellar evolution. We used the third signature scaling approach to fit a solar model for the convective blueshift to absorption-line shift measurements from a sample of coadded HARPS spectra, ranging in temperature from 3750K to 6150K.
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We compare the results to main sequence stars of comparable temperatures but with a higher surface gravity. We show that convective blueshift becomes significantly stronger for evolved stars compared to main sequence stars of a similar temperature. The difference increases as the star becomes more evolved, reaching a 5x increase below 4300K for the most evolved stars.
The large number of stars in the sample, for the first time, allowed for us to empirically show that convective blueshift remains almost constant among the entire evolved star sample at roughly solar convection strength with a slight increase from the red giant phase onward. We discover that the convective blueshift shows a local minimum for subgiant stars, presenting a sweet spot for exoplanet searches around higher mass stars, by taking advantage of their spin-down during the subgiant transition.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/673/A43 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2023A&A...673A..43L ui.adsabs.harvard.edu/abs/2023A%26A...673A..43L ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/a%2Ba/673/a43 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Optical
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Stellar astronomy and planetary systems 77%
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/673/a43 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:field:510109 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (77%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:optical | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |