Alderamin
Designations
- Bayer: α Cep
- Flamsteed: 5 Cep
- Hipparchos: HIP 105199
Data
- Constellation: Cepheus
- Apparent Magnitude: 2.46
- Right Ascension (J2000): 21h18m38.13s
- Declination (J2000): +62°35'09".2
- Colour Index (B-V): 0.22
- Distance: 49.05±0.08ly
Description
The star lies at the base of the House asterism or at the shoulder of the figure of Cepheus. To remember it and the second brightest star of the constellation Alfirk's presence within the House, use the mnemonic, "all the firken ramen is in the house!"
Nomenclature
Alderamin
Alderamin has a convoluted and unsure etymology. Renaissance scholars attributed the name to Arabic al-Ḏirā‘ al-Yamīn, 'the right arm', but Kunitzsch and Smart (2006) found this etymology to be doubly erroneous. For one, there is no "right arm" of the figure of Cepheus described in Ptolemy's Almagest, and instead α Cep is described as "on the shoulder". This would have been translated into Arabic as either al-katif or al-mankib. For two, the correct Arabic rendering of "the right arm" would be al-Ḏirā‘ al-Yumnā, which lacks assonance with Alderamin. Thus, they instead proposed the etymology of Alderamin being an abbreviation and bastardisation of Muqaddam al-Ḏirā‘ān, 'the preceding one of the two arms, or cubits', a scientific Arabic name for Castor (α Gem) based on the indigenous Arabic name for the asterism composed of Castor (α) and Pollux (β) Gem. The asterism depicted one of the arms of the figure al-Asad, 'the lion'.