Title
Abondances chimiques dans les premires toiles galactiques: tudes des lments plus lgers que le zinc et implications sur,Used
Delivery time: 8-12 business days (International)
33 toiles extrmement dficientes du halo galactique (ayant moins de 500 fois moins de mtaux que le Soleil) ont t observes haute rsolution spectroscopique. Ces toiles sont les tmoins des tous premiers ges de notre Galaxie. La connaissance dtaille de leur composition chimique permet de contraindre les modles de formation et d'volution de notre galaxie. Les abondances de 17 lments, allant du carbone au zinc, et en particulier, celles d'lments cls comme l'oxygne et le zinc, ont pu tre dtermines avec une prcision ingale. Cela permet une meilleure comprhension du type de supernova qui a enrichi la matire au dbut de la vie de la Galaxie. Par ailleurs, l'volution des abondances en fonction de la mtallicit moyenne est compare aux modles d'volution chimique de la Galaxie. Cette tude portant sur des toiles rputes tre nes au tout dbut de la vie de notre Galaxie, nous apportons des contraintes observationnelles fortes ces modles.
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Shipping & Returns
Shipping
We ship your order within 2–3 business days for USA deliveries and 5–8 business days for international shipments. Once your package has been dispatched from our warehouse, you'll receive an email confirmation with a tracking number, allowing you to track the status of your delivery.
Returns
To facilitate a smooth return process, a Return Authorization (RA) Number is required for all returns. Returns without a valid RA number will be declined and may incur additional fees. You can request an RA number within 15 days of the original delivery date. For more details, please refer to our Return & Refund Policy page.
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Warranty
We provide a 2-year limited warranty, from the date of purchase for all our products.
If you believe you have received a defective product, or are experiencing any problems with your product, please contact us.
This warranty strictly does not cover damages that arose from negligence, misuse, wear and tear, or not in accordance with product instructions (dropping the product, etc.).
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Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
We accept payments with :
Visa, MasterCard, American Express, Paypal, Shopify Payments, Shop Pay and more.